httplivestreambuffer.cpp

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/*****************************************************************************
 * httplivestreambuffer.cpp
 * MythTV
 *
 * Created by Jean-Yves Avenard on 6/05/12.
 * Copyright (c) 2012 Bubblestuff Pty Ltd. All rights reserved.
 *
 * Based on httplive.c by Jean-Paul Saman <jpsaman _AT_ videolan _DOT_ org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/
#include "httplivestreambuffer.h"
 
 
// QT
#include <QObject>
#include <QString>
#include <QStringList>
#include <QtAlgorithms>
#if QT_VERSION >= QT_VERSION_CHECK(6,0,0)
#include <QStringConverter>
#endif
#include <QUrl>
 
// C++
#include <algorithm> // for min/max
#include <array>
#include <thread>
 
// libmythbase
#include "libmythbase/mythconfig.h"
#include "libmythbase/mthread.h"
#include "libmythbase/mythdownloadmanager.h"
#include "libmythbase/mythlogging.h"
 
extern "C" {
#include "libavformat/avio.h"
}
 
#if CONFIG_LIBCRYPTO
// encryption related stuff
#include <openssl/aes.h>
#include <openssl/evp.h>
using aesiv_array = std::array<uint8_t,AES_BLOCK_SIZE>;
 
// 128-bit AES key for HLS segment decryption
static constexpr uint8_t AES128_KEY_SIZE { 16 };
struct hls_aes_key_st {
    std::array<uint8_t,AES128_KEY_SIZE> key;
};
using HLS_AES_KEY = struct hls_aes_key_st;
#endif
 
#define LOC QString("HLSBuffer: ")
 
// Constants
static constexpr int    PLAYBACK_MINBUFFER { 2 }; // number of segments to prefetch before playback starts
static constexpr int8_t PLAYBACK_READAHEAD { 6 }; // number of segments download queue ahead of playback
static constexpr int8_t PLAYLIST_FAILURE   { 6 }; // number of consecutive failures after which
                                                  // playback will abort
enum : std::int8_t
{
    RET_ERROR = -1,
    RET_OK    = 0,
};
 
/* utility methods */
 
static QString decoded_URI(const QString &uri)
{
    QByteArray ba   = uri.toLatin1();
    QUrl url        = QUrl::fromEncoded(ba);
    return url.toString();
}
 
static QString relative_URI(const QString &surl, const QString &spath)
{
    QUrl url  = QUrl(surl);
    QUrl path = QUrl(spath);
 
    if (!path.isRelative())
    {
        return spath;
    }
    return url.resolved(path).toString();
}
 
static std::chrono::microseconds mdate(void)
{
    return nowAsDuration<std::chrono::microseconds>();
}
 
static bool downloadURL(const QString &url, QByteArray *buffer, QString &finalURL)
{
    MythDownloadManager *mdm = GetMythDownloadManager();
    return mdm->download(url, buffer, false, &finalURL);
}
 
static bool downloadURL(const QString &url, QByteArray *buffer)
{
    MythDownloadManager *mdm = GetMythDownloadManager();
    return mdm->download(url, buffer);
}
 
static void cancelURL(const QString &url)
{
    MythDownloadManager *mdm = GetMythDownloadManager();
    mdm->cancelDownload(url);
}
 
static void cancelURL(const QStringList &urls)
{
    MythDownloadManager *mdm = GetMythDownloadManager();
    mdm->cancelDownload(urls);
}
 
/* segment container */
 
class HLSSegment
{
  public:
    HLSSegment(const std::chrono::seconds mduration, const int id, QString title,
               QString uri, [[maybe_unused]] QString current_key_path)
      : m_id(id),
        m_duration(mduration), // Seconds
        m_title(std::move(title)),
        m_url(std::move(uri))
    {
#if CONFIG_LIBCRYPTO
        //NOLINTNEXTLINE(cppcoreguidelines-prefer-member-initializer)
        m_pszKeyPath = std::move(current_key_path);
#endif
    }
 
    ~HLSSegment() = default;
 
    HLSSegment(const HLSSegment &rhs)
    {
        *this = rhs;
    }
 
    HLSSegment &operator=(const HLSSegment &rhs)
    {
        if (this == &rhs)
            return *this;
        m_id            = rhs.m_id;
        m_duration      = rhs.m_duration;
        m_bitrate       = rhs.m_bitrate;
        m_url           = rhs.m_url;
        // keep the old data downloaded
        // m_data       = m_data;
        // m_played     = m_played;
        m_title         = rhs.m_title;
#if CONFIG_LIBCRYPTO
        m_pszKeyPath    = rhs.m_pszKeyPath;
        memcpy(&m_aeskey, &(rhs.m_aeskey), sizeof(m_aeskey));
        m_keyloaded     = rhs.m_keyloaded;
#endif
        m_downloading   = rhs.m_downloading;
        return *this;
    }
 
    std::chrono::seconds Duration(void) const
    {
        return m_duration;
    }
 
    int Id(void) const
    {
        return m_id;
    }
 
    void Lock(void)
    {
        m_lock.lock();
    }
 
    void Unlock(void)
    {
        m_lock.unlock();
    }
 
    bool IsEmpty(void) const
    {
        return m_data.isEmpty();
    }
 
    int32_t Size(void) const
    {
        return m_data.size();
    }
 
    int Download(void)
    {
        // must own lock
        m_downloading = true;
        bool ret = downloadURL(m_url, &m_data);
        m_downloading = false;
        // didn't succeed, clear buffer
        if (!ret)
        {
            m_data.clear();
            return RET_ERROR;
        }
        return RET_OK;
    }
 
    void CancelDownload(void)
    {
        if (m_downloading)
        {
            cancelURL(m_url);
            QMutexLocker lock(&m_lock);
            m_downloading = false;
        }
    }
 
    QString Url(void) const
    {
        return m_url;
    }
 
    int32_t SizePlayed(void) const
    {
        return m_played;
    }
 
    uint32_t Read(uint8_t *buffer, int32_t length, FILE *fd = nullptr)
    {
        int32_t left = m_data.size() - m_played;
        length = std::min(length, left);
        if (buffer != nullptr)
        {
            memcpy(buffer, m_data.constData() + m_played, length);
            // write data to disk if required
            if (fd)
            {
                fwrite(m_data.constData() + m_played, length, 1, fd);
            }
        }
        m_played += length;
        return length;
    }
 
    void Reset(void)
    {
        m_played = 0;
    }
 
    void Clear(void)
    {
        m_played = 0;
        m_data.clear();
    }
 
    QString Title(void) const
    {
        return m_title;
    }
    void SetTitle(const QString &x)
    {
        m_title = x;
    }
    const char *Data(void) const
    {
        return m_data.constData();
    }
 
#if CONFIG_LIBCRYPTO
    int DownloadKey(void)
    {
        // must own lock
        if (m_keyloaded)
            return RET_OK;
        QByteArray key;
        bool ret = downloadURL(m_pszKeyPath, &key);
        if (!ret || key.size() != AES_BLOCK_SIZE)
        {
            if (ret)
            {
                LOG(VB_PLAYBACK, LOG_ERR, LOC +
                    QString("The AES key loaded doesn't have the right size (%1)")
                    .arg(key.size()));
            }
            else
            {
                LOG(VB_PLAYBACK, LOG_ERR, LOC + "Failed to download AES key");
            }
            return RET_ERROR;
        }
        memcpy(m_aeskey.key.data(), key.constData(), AES128_KEY_SIZE);
        m_keyloaded = true;
        return RET_OK;
    }
 
    // AES decryption based on OpenSSL example found on
    // https://wiki.openssl.org/index.php/EVP_Symmetric_Encryption_and_Decryption
    //
    static int Decrypt(unsigned char *ciphertext, int ciphertext_len, unsigned char *key,
                unsigned char *iv, unsigned char *plaintext)
    {
        int len = 0;
 
        int plaintext_len = 0;
 
        /* Create and initialise the context */
        EVP_CIPHER_CTX *ctx = EVP_CIPHER_CTX_new();
        if(!ctx)
        {
            LOG(VB_RECORD, LOG_ERR, LOC + "Failed to create and initialize cipher context");
            return 0;
        }
 
        /*
        * Initialise the decryption operation. IMPORTANT - ensure you use a key
        * and IV size appropriate for your cipher
        * In this example we are using 128 bit AES (i.e. a 128 bit key). The
        * IV size for *most* modes is the same as the block size. For AES this
        * is 128 bits
        */
        if(1 != EVP_DecryptInit_ex(ctx, EVP_aes_128_cbc(), NULL, key, iv))
        {
            LOG(VB_RECORD, LOG_ERR, LOC + "Failed to initialize decryption operation");
            return 0;
        }
 
        /*
        * Provide the message to be decrypted, and obtain the plaintext output.
        * EVP_DecryptUpdate can be called multiple times if necessary.
        */
        if(1 != EVP_DecryptUpdate(ctx, plaintext, &len, ciphertext, ciphertext_len))
        {
            LOG(VB_RECORD, LOG_ERR, LOC + "Failed to decrypt");
            return 0;
        }
        plaintext_len = len;
 
        /*
        * Finalise the decryption. Further plaintext bytes may be written at
        * this stage.
        */
        if(1 != EVP_DecryptFinal_ex(ctx, plaintext + len, &len))
        {
            LOG(VB_RECORD, LOG_ERR, LOC + "Failed to finalize decryption" +
                QString(" len:%1").arg(len) +
                QString(" plaintext_len:%1").arg(plaintext_len) );
            return 0;
        }
        plaintext_len += len;
 
        /* Clean up */
        EVP_CIPHER_CTX_free(ctx);
 
        return plaintext_len;
    }
 
    int DecodeData(const aesiv_array IV, bool iv_valid)
    {
        /* Decrypt data using AES-128 */
        aesiv_array iv {};
        auto *decrypted_data = new uint8_t[m_data.size()];
        if (!iv_valid)
        {
            /*
             * If the EXT-X-KEY tag does not have the IV attribute, implementations
             * MUST use the sequence number of the media file as the IV when
             * encrypting or decrypting that media file.  The big-endian binary
             * representation of the sequence number SHALL be placed in a 16-octet
             * buffer and padded (on the left) with zeros.
             */
            iv[15] = m_id         & 0xff;
            iv[14] = (m_id >> 8)  & 0xff;
            iv[13] = (m_id >> 16) & 0xff;
            iv[12] = (m_id >> 24) & 0xff;
        }
        else
        {
            std::ranges::copy(std::as_const(IV), iv.begin());
        }
 
        int aeslen = m_data.size() & ~0xf;
        if (aeslen != m_data.size())
        {
            LOG(VB_RECORD, LOG_WARNING, LOC +
                QString("Data size %1 not multiple of 16 bytes, rounding to %2")
                    .arg(m_data.size()).arg(aeslen));
        }
 
        int plaintext_len = Decrypt((unsigned char*)m_data.constData(), aeslen, m_aeskey.key.data(),
                                    iv.data(), decrypted_data);
 
        LOG(VB_RECORD, LOG_INFO, LOC +
            QString("Segment data.size()):%1 plaintext_len:%2")
                .arg(m_data.size()).arg(plaintext_len));
 
        m_data = QByteArray(reinterpret_cast<char*>(decrypted_data), plaintext_len);
        delete[] decrypted_data;
 
        return RET_OK;
    }
 
    bool HasKeyPath(void) const
    {
        return !m_pszKeyPath.isEmpty();
    }
 
    bool KeyLoaded(void) const
    {
        return m_keyloaded;
    }
 
    QString KeyPath(void) const
    {
        return m_pszKeyPath;
    }
 
    void SetKeyPath(const QString &path)
    {
        m_pszKeyPath = path;
    }
 
    void CopyAESKey(const HLSSegment &segment)
    {
        memcpy(&m_aeskey, &(segment.m_aeskey), sizeof(m_aeskey));
        m_keyloaded = segment.m_keyloaded;
    }
private:
    HLS_AES_KEY m_aeskey    {};         // AES-128 key
    bool        m_keyloaded {false};
    QString     m_pszKeyPath;           // URL key path
#endif
 
private:
    int         m_id       {0}; // unique sequence number
    std::chrono::seconds m_duration {0s}; // segment duration
    uint64_t    m_bitrate {0};  // bitrate of segment's content (bits per second)
    QString     m_title;        // human-readable informative title of the media segment
 
    QString     m_url;
    QByteArray  m_data;         // raw data
    int32_t     m_played  {0};  // bytes counter of data already read from segment
    QMutex      m_lock;
    bool        m_downloading {false};
};
 
/* stream class */
 
class HLSStream
{
  public:
    HLSStream(const int mid, const uint64_t bitrate, QString uri)
      : m_id(mid),
        m_bitrate(bitrate),
        m_url(std::move(uri))
    {
#if CONFIG_LIBCRYPTO
        m_aesIv.fill(0);
#endif
    }
 
    HLSStream(const HLSStream &rhs, bool copy = true)
    {
        (*this) = rhs;
        if (!copy)
            return;
        // copy all the segments across
        for (auto *old : std::as_const(m_segments))
        {
            auto *segment = new HLSSegment(*old);
            AppendSegment(segment);
        }
    }
 
    ~HLSStream()
    {
        for (const auto & segment : std::as_const(m_segments))
            delete segment;
    }
 
    HLSStream &operator=(const HLSStream &rhs)
    {
        if (this == &rhs)
            return *this;
        // do not copy segments
        m_id            = rhs.m_id;
        m_version       = rhs.m_version;
        m_startsequence = rhs.m_startsequence;
        m_targetduration= rhs.m_targetduration;
        m_bitrate       = rhs.m_bitrate;
        m_size          = rhs.m_size;
        m_duration      = rhs.m_duration;
        m_live          = rhs.m_live;
        m_url           = rhs.m_url;
        m_cache         = rhs.m_cache;
#if CONFIG_LIBCRYPTO
        m_keypath       = rhs.m_keypath;
        m_ivloaded      = rhs.m_ivloaded;
        m_aesIv         = rhs.m_aesIv;
#endif
        return *this;
    }
 
    static bool IsGreater(const HLSStream *s1, const HLSStream *s2)
    {
        return s1->Bitrate() > s2->Bitrate();
    }
 
    bool operator<(const HLSStream &b) const
    {
        return this->Bitrate() < b.Bitrate();
    }
 
    bool operator>(const HLSStream &b) const
    {
        return this->Bitrate() > b.Bitrate();
    }
 
    uint64_t Size(bool force = false)
    {
        if (m_size > 0 && !force)
            return m_size;
        QMutexLocker lock(&m_lock);
 
        int64_t size    = 0;
        int count       = NumSegments();
 
        for (int i = 0; i < count; i++)
        {
            HLSSegment *segment = GetSegment(i);
            segment->Lock();
            if (segment->Size() > 0)
            {
                size += (int64_t)segment->Size();
            }
            else
            {
                size += segment->Duration().count() * Bitrate() / 8;
            }
            segment->Unlock();
        }
        m_size = size;
        return m_size;
    }
 
    std::chrono::seconds Duration(void)
    {
        QMutexLocker lock(&m_lock);
        return m_duration;
    }
 
    void Clear(void)
    {
        m_segments.clear();
    }
 
    int NumSegments(void) const
    {
        return m_segments.size();
    }
 
    void AppendSegment(HLSSegment *segment)
    {
        // must own lock
        m_segments.append(segment);
    }
 
    HLSSegment *GetSegment(const int wanted) const
    {
        int count = NumSegments();
        if (count <= 0)
            return nullptr;
        if ((wanted < 0) || (wanted >= count))
            return nullptr;
        return m_segments[wanted];
    }
 
    HLSSegment *FindSegment(const int id, int *segnum = nullptr) const
    {
        int count = NumSegments();
        if (count <= 0)
            return nullptr;
        for (int n = 0; n < count; n++)
        {
            HLSSegment *segment = GetSegment(n);
            if (segment == nullptr)
                break;
            if (segment->Id() == id)
            {
                if (segnum != nullptr)
                {
                    *segnum = n;
                }
                return segment;
            }
        }
        return nullptr;
    }
 
    void AddSegment(const std::chrono::seconds duration, const QString &title, const QString &uri)
    {
        QMutexLocker lock(&m_lock);
        QString psz_uri = relative_URI(m_url, uri);
        int id = NumSegments() + m_startsequence;
#if !CONFIG_LIBCRYPTO
        QString m_keypath;
#endif
        auto *segment = new HLSSegment(duration, id, title, psz_uri, m_keypath);
        AppendSegment(segment);
        m_duration += duration;
    }
 
    void RemoveSegment(HLSSegment *segment, bool willdelete = true)
    {
        QMutexLocker lock(&m_lock);
        m_duration -= segment->Duration();
        if (willdelete)
        {
            delete segment;
        }
        int count = NumSegments();
        if (count <= 0)
            return;
        for (int n = 0; n < count; n++)
        {
            HLSSegment *old = GetSegment(n);
            if (old == segment)
            {
                m_segments.removeAt(n);
                break;
            }
        }
    }
 
    void RemoveSegment(int segnum, bool willdelete = true)
    {
        QMutexLocker lock(&m_lock);
        HLSSegment *segment = GetSegment(segnum);
        if (segment != nullptr)
        {
            m_duration -= segment->Duration();
            if (willdelete)
                delete segment;
        }
        m_segments.removeAt(segnum);
    }
 
    void RemoveListSegments(QHash<HLSSegment*,bool> &table)
    {
        for (auto it = table.begin(); it != table.end(); ++it)
        {
            bool todelete   = *it;
            HLSSegment *p   = it.key();
            RemoveSegment(p, todelete);
        }
    }
 
    int DownloadSegmentData(int segnum, uint64_t &bandwidth, int stream)
    {
        HLSSegment *segment = GetSegment(segnum);
        if (segment == nullptr)
            return RET_ERROR;
 
        segment->Lock();
        if (!segment->IsEmpty())
        {
            /* Segment already downloaded */
            segment->Unlock();
            return RET_OK;
        }
 
        LOG(VB_PLAYBACK, LOG_DEBUG, LOC +
            QString("started download of segment %1 [%2/%3] using stream %4")
            .arg(segnum).arg(segment->Id()).arg(NumSegments()+m_startsequence)
            .arg(stream));
 
        /* sanity check - can we download this segment on time? */
        if ((bandwidth > 0) && (m_bitrate > 0))
        {
            uint64_t size = (segment->Duration().count() * m_bitrate); /* bits */
            auto estimated = std::chrono::seconds(size / bandwidth);
            if (estimated > segment->Duration())
            {
                LOG(VB_PLAYBACK, LOG_INFO, LOC +
                    QString("downloading of segment %1 [id:%2] will take %3s, "
                            "which is longer than its playback (%4s) at %5bit/s")
                    .arg(segnum)
                    .arg(segment->Id())
                    .arg(estimated.count())
                    .arg(segment->Duration().count())
                    .arg(bandwidth));
            }
        }
 
        std::chrono::microseconds start = mdate();
        if (segment->Download() != RET_OK)
        {
            LOG(VB_PLAYBACK, LOG_ERR, LOC +
                QString("downloaded segment %1 [id:%2] from stream %3 failed")
                .arg(segnum).arg(segment->Id()).arg(m_id));
            segment->Unlock();
            return RET_ERROR;
        }
 
        std::chrono::microseconds downloadduration = mdate() - start;
        if (m_bitrate == 0 && segment->Duration() > 0s)
        {
            /* Try to estimate the bandwidth for this stream */
            m_bitrate = (uint64_t)(((double)segment->Size() * 8) /
                                   ((double)segment->Duration().count()));
        }
 
#if CONFIG_LIBCRYPTO
        /* If the segment is encrypted, decode it */
        if (segment->HasKeyPath())
        {
            /* Do we have loaded the key ? */
            if (!segment->KeyLoaded())
            {
                if (ManageSegmentKeys() != RET_OK)
                {
                    LOG(VB_PLAYBACK, LOG_ERR, LOC +
                        "couldn't retrieve segment AES-128 key");
                    segment->Unlock();
                    return RET_OK;
                }
            }
            if (segment->DecodeData(m_aesIv, m_ivloaded) != RET_OK)
            {
                segment->Unlock();
                return RET_ERROR;
            }
        }
#endif
        segment->Unlock();
 
        downloadduration = std::max(1us, downloadduration);
        bandwidth = segment->Size() * 8ULL * 1000000ULL / downloadduration.count(); /* bits / s */
        LOG(VB_PLAYBACK, LOG_DEBUG, LOC +
            QString("downloaded segment %1 [id:%2] took %3ms for %4 bytes: bandwidth:%5kiB/s")
            .arg(segnum)
            .arg(segment->Id())
            .arg(duration_cast<std::chrono::milliseconds>(downloadduration).count())
            .arg(segment->Size())
            .arg(bandwidth / 8192.0));
 
        return RET_OK;
    }
    int Id(void) const
    {
        return m_id;
    }
    int Version(void) const
    {
        return m_version;
    }
    void SetVersion(int x)
    {
        m_version = x;
    }
    int StartSequence(void) const
    {
        return m_startsequence;
    }
    void SetStartSequence(int x)
    {
        m_startsequence = x;
    }
    std::chrono::seconds TargetDuration(void) const
    {
        return m_targetduration;
    }
    void SetTargetDuration(std::chrono::seconds x)
    {
        m_targetduration = x;
    }
    uint64_t Bitrate(void) const
    {
        return m_bitrate;
    }
    bool Cache(void) const
    {
        return m_cache;
    }
    void SetCache(bool x)
    {
        m_cache = x;
    }
    bool Live(void) const
    {
        return m_live;
    }
    void SetLive(bool x)
    {
        m_live = x;
    }
    void Lock(void)
    {
        m_lock.lock();
    }
    void Unlock(void)
    {
        m_lock.unlock();
    }
    QString Url(void) const
    {
        return m_url;
    }
    void UpdateWith(const HLSStream &upd)
    {
        QMutexLocker lock(&m_lock);
        m_targetduration    = upd.m_targetduration < 0s ?
            m_targetduration : upd.m_targetduration;
        m_cache             = upd.m_cache;
    }
    void Cancel(void)
    {
        QMutexLocker lock(&m_lock);
        for (const auto & segment : std::as_const(m_segments))
        {
            if (segment)
            {
                segment->CancelDownload();
            }
        }
    }
 
#if CONFIG_LIBCRYPTO
    int ManageSegmentKeys() const
    {
        HLSSegment   *seg       = nullptr;
        HLSSegment   *prev_seg  = nullptr;
        int          count      = NumSegments();
 
        for (int i = 0; i < count; i++)
        {
            prev_seg = seg;
            seg = GetSegment(i);
            if (seg == nullptr )
                continue;
            if (!seg->HasKeyPath())
                continue;   /* No key to load ? continue */
            if (seg->KeyLoaded())
                continue;   /* The key is already loaded */
 
            /* if the key has not changed, and already available from previous segment,
             * try to copy it, and don't load the key */
            if (prev_seg && prev_seg->KeyLoaded() &&
                (seg->KeyPath() == prev_seg->KeyPath()))
            {
                seg->CopyAESKey(*prev_seg);
                continue;
            }
            if (seg->DownloadKey() != RET_OK)
                return RET_ERROR;
        }
        return RET_OK;
    }
    bool SetAESIV(QString line)
    {
        /*
         * If the EXT-X-KEY tag has the IV attribute, implementations MUST use
         * the attribute value as the IV when encrypting or decrypting with that
         * key.  The value MUST be interpreted as a 128-bit hexadecimal number
         * and MUST be prefixed with 0x or 0X.
         */
        if (!line.startsWith(QLatin1String("0x"), Qt::CaseInsensitive))
            return false;
        if (line.size() % 2)
        {
            // not even size, pad with front 0
            line.insert(2, QLatin1String("0"));
        }
#if QT_VERSION < QT_VERSION_CHECK(6,0,0)
        int padding = std::max(0, AES_BLOCK_SIZE - (line.size() - 2));
#else
        int padding = std::max(static_cast<qsizetype>(0), AES_BLOCK_SIZE - (line.size() - 2));
#endif
        QByteArray ba = QByteArray(padding, 0x0);
        ba.append(QByteArray::fromHex(QByteArray(line.toLatin1().constData() + 2)));
        std::ranges::copy(std::as_const(ba), m_aesIv.begin());
        m_ivloaded = true;
        return true;
    }
    aesiv_array AESIV(void)
    {
        return m_aesIv;
    }
    void SetKeyPath(const QString &x)
    {
        m_keypath = x;
    }
 
private:
    QString     m_keypath;              // URL path of the encrypted key
    bool        m_ivloaded       {false};
    aesiv_array m_aesIv          {0};   // IV used when decypher the block
#endif
 
private:
    int         m_id             {0};   // program id
    int         m_version        {1};   // protocol version should be 1
    int         m_startsequence  {0};   // media starting sequence number
    std::chrono::seconds m_targetduration {-1s};  // maximum duration per segment
    uint64_t    m_bitrate        {0LL}; // bitrate of stream content (bits per second)
    uint64_t    m_size           {0LL}; // stream length is calculated by taking the sum
                                        // foreach segment of (segment->duration * hls->bitrate/8)
    std::chrono::seconds m_duration       {0s}; // duration of the stream
    bool        m_live           {true};
 
    QList<HLSSegment*> m_segments;      // list of segments
    QString     m_url;                  // uri to m3u8
    QMutex      m_lock;
    bool        m_cache          {true};// allow caching
};
 
// Playback Stream Information
class HLSPlayback
{
public:
    HLSPlayback(void) = default;
 
    /* offset is only used from main thread, no need for locking */
    uint64_t Offset(void) const
    {
        return m_offset;
    }
    void SetOffset(uint64_t val)
    {
        m_offset = val;
    }
    void AddOffset(uint64_t val)
    {
        m_offset += val;
    }
    int Stream(void)
    {
        QMutexLocker lock(&m_lock);
        return m_stream;
    }
    void SetStream(int val)
    {
        QMutexLocker lock(&m_lock);
        m_stream = val;
    }
    int Segment(void)
    {
        QMutexLocker lock(&m_lock);
        return m_segment;
    }
    void SetSegment(int val)
    {
        QMutexLocker lock(&m_lock);
        m_segment = val;
    }
    int IncrSegment(void)
    {
        QMutexLocker lock(&m_lock);
        return ++m_segment;
    }
 
private:
    uint64_t        m_offset {0};   // current offset in media
    int             m_stream {0};   // current HLSStream
    int             m_segment {0};  // current segment for playback
    QMutex          m_lock;
};
 
// Stream Download Thread
class StreamWorker : public MThread
{
public:
    StreamWorker(HLSRingBuffer *parent, int startup, int buffer) : MThread("HLSStream"),
        m_parent(parent), m_segment(startup), m_buffer(buffer)
    {
    }
    void Cancel(void)
    {
        m_interrupted = true;
        Wakeup();
        m_lock.lock();
        // Interrupt on-going downloads of all segments
        int streams = m_parent->NumStreams();
        for (int i = 0; i < streams; i++)
        {
            HLSStream *hls = m_parent->GetStream(i);
            if (hls)
            {
                hls->Cancel();
            }
        }
        m_lock.unlock();
        wait();
    }
    int CurrentStream(void)
    {
        QMutexLocker lock(&m_lock);
        return m_stream;
    }
    int Segment(void)
    {
        QMutexLocker lock(&m_lock);
        return m_segment;
    }
    void Seek(int val)
    {
        m_lock.lock();
        m_segment = val;
        m_lock.unlock();
        Wakeup();
    }
    bool IsAtEnd(bool lock = false)
    {
        if (lock)
        {
            m_lock.lock();
        }
        int count = m_parent->NumSegments();
        bool ret = m_segment >= count;
        if (lock)
        {
            m_lock.unlock();
        }
        return ret;
    }
 
    bool GotBufferedSegments(int from, int count) const
    {
        if (from + count > m_parent->NumSegments())
            return false;
 
        for (int i = from; i < from + count; i++)
        {
            if (StreamForSegment(i, false) < 0)
            {
                return false;
            }
        }
        return true;
    }
 
    int CurrentPlaybackBuffer(bool lock = true)
    {
        if (lock)
        {
            m_lock.lock();
        }
        int ret = m_segment - m_parent->m_playback->Segment();
        if (lock)
        {
            m_lock.unlock();
        }
        return ret;
    }
    int CurrentLiveBuffer(void)
    {
        return m_parent->NumSegments() - m_segment;
    }
    void SetBuffer(int val)
    {
        QMutexLocker lock(&m_lock);
        m_buffer = val;
    }
    void AddSegmentToStream(int segnum, int stream)
    {
        if (m_interrupted)
            return;
        QMutexLocker lock(&m_lock);
        m_segmap.insert(segnum, stream);
    }
    void RemoveSegmentFromStream(int segnum)
    {
        QMutexLocker lock(&m_lock);
        m_segmap.remove(segnum);
    }
 
    int StreamForSegment(int segmentid, bool lock = true) const
    {
        if (lock)
        {
            m_lock.lock();
        }
        int ret = 0;
        if (!m_segmap.contains(segmentid))
        {
            ret = -1; // we never downloaded that segment on any streams
        }
        else
        {
            ret = m_segmap[segmentid];
        }
        if (lock)
        {
            m_lock.unlock();
        }
        return ret;
    }
 
    void Wakeup(void)
    {
        // send a wake signal
        m_waitcond.wakeAll();
    }
    void WaitForSignal(std::chrono::milliseconds time = std::chrono::milliseconds::max())
    {
        // must own lock
        m_waitcond.wait(&m_lock, time.count());
    }
    void Lock(void)
    {
        m_lock.lock();
    }
    void Unlock(void)
    {
        m_lock.unlock();
    }
    int64_t Bandwidth(void) const
    {
        return m_bandwidth;
    }
    double AverageNewBandwidth(int64_t bandwidth)
    {
        m_sumbandwidth += bandwidth;
        m_countbandwidth++;
        m_bandwidth = m_sumbandwidth / m_countbandwidth;
        return m_bandwidth;
    }
 
protected:
    void run(void) override // MThread
    {
        RunProlog();
 
        int retries = 0;
        while (!m_interrupted)
        {
            /*
             * we can go into waiting if:
             * - not live and download is more than 3 segments ahead of playback
             * - we are at the end of the stream
             */
            Lock();
            HLSStream *hls  = m_parent->GetStream(m_stream);
            if (hls == nullptr)
            {
                // an irrevocable error has occured. exit
                Wakeup();
                break;
            }
 
            int dnldsegment = m_segment;
            int playsegment = m_parent->m_playback->Segment();
            if ((!hls->Live() && (playsegment < dnldsegment - m_buffer)) ||
                IsAtEnd())
            {
                /* wait until
                 * 1- got interrupted
                 * 2- we are less than 6 segments ahead of playback
                 * 3- got asked to seek to a particular segment */
                while (!m_interrupted && (m_segment == dnldsegment) &&
                       (((m_segment - playsegment) > m_buffer) || IsAtEnd()))
                {
                    WaitForSignal();
                    // do we have new segments available added by PlaylistWork?
                    if (hls->Live() && !IsAtEnd())
                        break;
                    playsegment = m_parent->m_playback->Segment();
                }
                dnldsegment = m_segment;
            }
            Unlock();
 
            if (m_interrupted)
            {
                Wakeup();
                break;
            }
            // have we already downloaded the required segment?
            if (StreamForSegment(dnldsegment) < 0)
            {
                uint64_t bw = m_bandwidth;
                int err = hls->DownloadSegmentData(dnldsegment, bw, m_stream);
                if (m_interrupted)
                {
                    // interrupt early
                    Wakeup();
                    break;
                }
                bw = AverageNewBandwidth(bw);
                if (err != RET_OK)
                {
                    retries++;
                    LOG(VB_PLAYBACK, LOG_DEBUG, LOC +
                        QString("download failed, retry #%1").arg(retries));
                    if (retries == 1)   // first error
                        continue;       // will retry immediately
                    std::this_thread::sleep_for(500ms);
                    if (retries == 2)   // and retry once again
                        continue;
                    if (!m_parent->m_meta) // NOLINT(bugprone-branch-clone)
                    {
                        // no other stream to default to, skip packet
                        retries = 0;
                    }
                    else
                    {
                        // TODO: should switch to another stream
                        retries = 0;
                    }
                }
                else
                {
                    LOG(VB_PLAYBACK, LOG_DEBUG, LOC +
                        QString("download completed, %1 segments ahead")
                        .arg(CurrentLiveBuffer()));
                    AddSegmentToStream(dnldsegment, m_stream);
                    if (m_parent->m_meta && hls->Bitrate() != bw)
                    {
                        int newstream = BandwidthAdaptation(hls->Id(), bw);
 
                        if (newstream >= 0 && newstream != m_stream)
                        {
                            LOG(VB_PLAYBACK, LOG_INFO, LOC +
                                QString("switching to %1 bitrate %2 stream; changing "
                                        "from stream %3 to stream %4")
                                .arg(bw >= hls->Bitrate() ? "faster" : "lower")
                                .arg(bw).arg(m_stream).arg(newstream));
                            m_stream = newstream;
                        }
                    }
                }
            }
            Lock();
            if (dnldsegment == m_segment)   // false if seek was called
            {
                m_segment++;
            }
            Unlock();
            // Signal we're done
            Wakeup();
        }
 
        RunEpilog();
    }
 
    int BandwidthAdaptation(int progid, uint64_t &bandwidth) const
    {
        int candidate = -1;
        uint64_t bw = bandwidth;
        uint64_t bw_candidate = 0;
 
        int count = m_parent->NumStreams();
        for (int n = 0; n < count; n++)
        {
            /* Select best bandwidth match */
            HLSStream *hls = m_parent->GetStream(n);
            if (hls == nullptr)
                break;
 
            /* only consider streams with the same PROGRAM-ID */
            if (hls->Id() == progid)
            {
                if ((bw >= hls->Bitrate()) &&
                    (bw_candidate < hls->Bitrate()))
                {
                    LOG(VB_PLAYBACK, LOG_DEBUG, LOC +
                        QString("candidate stream %1 bitrate %2 >= %3")
                        .arg(n).arg(bw).arg(hls->Bitrate()));
                    bw_candidate = hls->Bitrate();
                    candidate = n; /* possible candidate */
                }
            }
        }
        bandwidth = bw_candidate;
        return candidate;
    }
 
private:
    HLSRingBuffer  *m_parent         {nullptr};
    volatile bool   m_interrupted    {false};
                    // measured average download bandwidth (bits per second)
    int64_t         m_bandwidth      {0};
    int             m_stream         {0};// current HLSStream
    int             m_segment;  // current segment for downloading
    int             m_buffer;   // buffer kept between download and playback
    QMap<int,int>   m_segmap;   // segment with streamid used for download
    mutable QMutex  m_lock;
    QWaitCondition  m_waitcond;
    double          m_sumbandwidth   {0.0};
    int             m_countbandwidth {0};
};
 
// Playlist Refresh Thread
class PlaylistWorker : public MThread
{
public:
    PlaylistWorker(HLSRingBuffer *parent, std::chrono::milliseconds wait) : MThread("HLSStream"),
        m_parent(parent), m_wakeup(wait) {}
    void Cancel()
    {
        m_interrupted = true;
        Wakeup();
        m_lock.lock();
        // Interrupt on-going downloads of all stream playlists
        int streams = m_parent->NumStreams();
        QStringList listurls;
        listurls.reserve(streams);
        for (int i = 0; i < streams; i++)
        {
            HLSStream *hls = m_parent->GetStream(i);
            if (hls)
            {
                listurls.append(hls->Url());
            }
        }
        m_lock.unlock();
        cancelURL(listurls);
        wait();
    }
 
    void Wakeup(void)
    {
        m_lock.lock();
        m_wokenup = true;
        m_lock.unlock();
        // send a wake signal
        m_waitcond.wakeAll();
    }
    void WaitForSignal(std::chrono::milliseconds time = std::chrono::milliseconds::max())
    {
        // must own lock
        m_waitcond.wait(&m_lock, time.count());
    }
    void Lock(void)
    {
        m_lock.lock();
    }
    void Unlock(void)
    {
        m_lock.unlock();
    }
 
protected:
    void run(void) override // MThread
    {
        RunProlog();
 
        HLSStream *hls = m_parent->GetCurrentStream();
        bool live = hls ? hls->Live() : false;
        double wait = 0.5;
        double factor = live ? 1.0 : 2.0;
 
        QWaitCondition mcond;
 
        while (!m_interrupted)
        {
            if (m_parent->m_streamworker == nullptr)
            {
                // streamworker not running
                LOG(VB_PLAYBACK, LOG_ERR, LOC +
                    "StreamWorker not running, aborting live playback");
                m_interrupted = true;
                break;
            }
 
            Lock();
            if (!m_wokenup)
            {
                std::chrono::milliseconds waittime = std::max(100ms, m_wakeup);
                LOG(VB_PLAYBACK, LOG_DEBUG, LOC +
                    QString("PlayListWorker refreshing in %1s")
                    .arg(duration_cast<std::chrono::seconds>(waittime).count()));
                WaitForSignal(waittime);
            }
            m_wokenup = false;
            Unlock();
 
            /* reload the m3u8 */
            if (ReloadPlaylist() != RET_OK)
            {
                /* No change in playlist, then backoff */
                m_retries++;
                if (m_retries == 1)       wait = 0.5;
                else if (m_retries == 2)  wait = 1;
                else if (m_retries >= 3)  wait = 2;
 
                // If we haven't been able to reload the playlist after x times
                // it probably means the stream got deleted, so abort
                if (m_retries > PLAYLIST_FAILURE)
                {
                    LOG(VB_PLAYBACK, LOG_ERR, LOC +
                        QString("reloading the playlist failed after %1 attempts."
                                "aborting.").arg(PLAYLIST_FAILURE));
                    m_parent->m_error = true;
                }
 
                /* Can we afford to backoff? */
                if (m_parent->m_streamworker->CurrentPlaybackBuffer() < 3)
                {
                    if (m_retries == 1)
                        continue; // restart immediately if it's the first try
                    m_retries = 0;
                    wait = 0.5;
                }
            }
            else
            {
                // make streamworker process things
                m_parent->m_streamworker->Wakeup();
                m_retries = 0;
                wait = 0.5;
            }
 
            if (hls == nullptr)
            {
                // an irrevocable error has occured. exit
                LOG(VB_PLAYBACK, LOG_ERR, LOC +
                    "unable to retrieve current stream, aborting live playback");
                m_interrupted = true;
                break;
            }
 
            /* determine next time to update playlist */
            m_wakeup = duration_cast<std::chrono::milliseconds>(
                hls->TargetDuration() * wait * factor);
        }
 
        RunEpilog();
    }
 
private:
    int ReloadPlaylist(void)
    {
        auto *streams = new StreamsList;
 
        LOG(VB_PLAYBACK, LOG_INFO, LOC + "reloading HLS live meta playlist");
 
        if (GetHTTPLiveMetaPlaylist(streams) != RET_OK)
        {
            LOG(VB_PLAYBACK, LOG_ERR, LOC + "reloading playlist failed");
            m_parent->FreeStreamsList(streams);
            return RET_ERROR;
        }
 
        /* merge playlists */
        int count = streams->size();
        for (int n = 0; n < count; n++)
        {
            HLSStream *hls_new = m_parent->GetStream(n, streams);
            if (hls_new == nullptr)
                continue;
 
            HLSStream *hls_old = m_parent->FindStream(hls_new);
            if (hls_old == nullptr)
            {   /* new hls stream - append */
                m_parent->m_streams.append(hls_new);
                LOG(VB_PLAYBACK, LOG_INFO, LOC +
                    QString("new HLS stream appended (id=%1, bitrate=%2)")
                    .arg(hls_new->Id()).arg(hls_new->Bitrate()));
            }
            else if (UpdatePlaylist(hls_new, hls_old) != RET_OK)
            {
                LOG(VB_PLAYBACK, LOG_ERR, LOC +
                    QString("failed updating HLS stream (id=%1, bandwidth=%2)")
                    .arg(hls_new->Id()).arg(hls_new->Bitrate()));
                m_parent->FreeStreamsList(streams);
                return RET_ERROR;
            }
        }
        delete streams;
        return RET_OK;
    }
 
    static int UpdatePlaylist(HLSStream *hls_new, HLSStream *hls)
    {
        int count = hls_new->NumSegments();
 
        LOG(VB_PLAYBACK, LOG_INFO, LOC +
            QString("updated hls stream (program-id=%1, bitrate=%2) has %3 segments")
            .arg(hls_new->Id()).arg(hls_new->Bitrate()).arg(count));
        QHash<HLSSegment*,bool> table;
 
        for (int n = 0; n < count; n++)
        {
            HLSSegment *p = hls_new->GetSegment(n);
            if (p == nullptr)
                return RET_ERROR;
 
            hls->Lock();
            HLSSegment *segment = hls->FindSegment(p->Id());
            if (segment)
            {
                segment->Lock();
                /* they should be the same */
                if ((p->Id() != segment->Id()) ||
                    (p->Duration() != segment->Duration()) ||
                    (p->Url() != segment->Url()))
                {
                    LOG(VB_PLAYBACK, LOG_WARNING, LOC +
                        QString("existing segment found with different content - resetting"));
                    LOG(VB_PLAYBACK, LOG_WARNING, LOC +
                        QString("-       id: new=%1, old=%2")
                        .arg(p->Id()).arg(segment->Id()));
                    LOG(VB_PLAYBACK, LOG_WARNING, LOC +
                        QString("- duration: new=%1, old=%2")
                        .arg(p->Duration().count()).arg(segment->Duration().count()));
                    LOG(VB_PLAYBACK, LOG_WARNING, LOC +
                        QString("-     file: new=%1 old=%2")
                        .arg(p->Url(), segment->Url()));
 
                    /* Resetting content */
                    *segment = *p;
                }
                // mark segment to be removed from new stream, and deleted
                table.insert(p, true);
                segment->Unlock();
            }
            else
            {
                int last = hls->NumSegments() - 1;
                HLSSegment *l = hls->GetSegment(last);
                if (l == nullptr)
                {
                    hls->Unlock();
                    return RET_ERROR;
                }
 
                if ((l->Id() + 1) != p->Id())
                {
                    LOG(VB_PLAYBACK, LOG_ERR, LOC +
                        QString("gap in id numbers found: new=%1 expected %2")
                        .arg(p->Id()).arg(l->Id()+1));
                }
                hls->AppendSegment(p);
                LOG(VB_PLAYBACK, LOG_INFO, LOC +
                    QString("- segment %1 appended")
                    .arg(p->Id()));
                // segment was moved to another stream, so do not delete it
                table.insert(p, false);
            }
            hls->Unlock();
        }
        hls_new->RemoveListSegments(table);
 
        /* update meta information */
        hls->UpdateWith(*hls_new);
        return RET_OK;
    }
 
    int GetHTTPLiveMetaPlaylist(StreamsList *streams)
    {
        int err = RET_ERROR;
 
        /* Duplicate HLS stream META information */
        for (int i = 0; i < m_parent->m_streams.size() && !m_interrupted; i++)
        {
            auto *src = m_parent->GetStream(i);
            if (src == nullptr)
                return RET_ERROR;
 
            auto *dst = new HLSStream(*src);
            streams->append(dst);
 
            /* Download playlist file from server */
            QByteArray buffer;
            if (!downloadURL(dst->Url(), &buffer) || m_interrupted)
            {
                return RET_ERROR;
            }
            /* Parse HLS m3u8 content. */
            err = m_parent->ParseM3U8(&buffer, streams);
        }
        m_parent->SanitizeStreams(streams);
        return err;
    }
 
    // private variable members
    HLSRingBuffer * m_parent      {nullptr};
    bool            m_interrupted {false};
    std::chrono::milliseconds m_wakeup;       // next reload time
    int             m_retries     {0}; // number of consecutive failures
    bool            m_wokenup     {false};
    QMutex          m_lock;
    QWaitCondition  m_waitcond;
};
 
HLSRingBuffer::HLSRingBuffer(const QString &lfilename) :
    MythMediaBuffer(kMythBufferHLS),
    m_playback(new HLSPlayback())
{
    m_startReadAhead = false;
    HLSRingBuffer::OpenFile(lfilename);
}
 
HLSRingBuffer::HLSRingBuffer(const QString &lfilename, bool open) :
    MythMediaBuffer(kMythBufferHLS),
    m_playback(new HLSPlayback())
{
    m_startReadAhead = false;
    if (open)
    {
        HLSRingBuffer::OpenFile(lfilename);
    }
}
 
HLSRingBuffer::~HLSRingBuffer()
{
    KillReadAheadThread();
 
    QWriteLocker lock(&m_rwLock);
 
    m_killed = true;
 
    if (m_playlistworker)
    {
        m_playlistworker->Cancel();
        delete m_playlistworker;
    }
    // stream worker must be deleted after playlist worker
    if (m_streamworker)
    {
        m_streamworker->Cancel();
        delete m_streamworker;
    }
    FreeStreamsList(&m_streams);
    delete m_playback;
    if (m_fd)
    {
        fclose(m_fd);
    }
}
 
void HLSRingBuffer::FreeStreamsList(StreamsList *streams) const
{
    /* Free hls streams */
    for (int i = 0; i < streams->size(); i++)
    {
        HLSStream *hls = GetStream(i, streams);
        delete hls;
    }
    if (streams != &m_streams)
    {
        delete streams;
    }
}
 
HLSStream *HLSRingBuffer::GetStreamForSegment(int segnum) const
{
    int stream = m_streamworker->StreamForSegment(segnum);
    if (stream < 0)
    {
        return GetCurrentStream();
    }
    return GetStream(stream);
}
 
HLSStream *HLSRingBuffer::GetStream(const int wanted, const StreamsList *streams) const
{
    if (streams == nullptr)
    {
        streams = &m_streams;
    }
    int count = streams->size();
    if (count <= 0)
        return nullptr;
    if ((wanted < 0) || (wanted >= count))
        return nullptr;
    return streams->at(wanted);
}
 
HLSStream *HLSRingBuffer::GetFirstStream(const StreamsList *streams) const
{
    return GetStream(0, streams);
}
 
HLSStream *HLSRingBuffer::GetLastStream(const StreamsList *streams) const
{
    if (streams == nullptr)
    {
        streams = &m_streams;
    }
    int count = streams->size();
    if (count <= 0)
        return nullptr;
    count--;
    return GetStream(count, streams);
}
 
HLSStream *HLSRingBuffer::FindStream(const HLSStream *hls_new,
                                     const StreamsList *streams) const
{
    if (streams == nullptr)
    {
        streams = &m_streams;
    }
    int count = streams->size();
    for (int n = 0; n < count; n++)
    {
        HLSStream *hls = GetStream(n, streams);
        if (hls)
        {
            /* compare */
            if ((hls->Id() == hls_new->Id()) &&
                ((hls->Bitrate() == hls_new->Bitrate()) ||
                 (hls_new->Bitrate() == 0)))
            {
                return hls;
            }
        }
    }
    return nullptr;
}
 
HLSStream *HLSRingBuffer::GetCurrentStream(void) const
{
    if (!m_streamworker)
    {
        return nullptr;
    }
    return GetStream(m_streamworker->CurrentStream());
}
 
bool HLSRingBuffer::IsHTTPLiveStreaming(QByteArray *s)
{
    if (!s || s->size() < 7)
        return false;
 
    if (!s->startsWith((const char*)"#EXTM3U"))
        return false;
 
    QTextStream stream(s);
    /* Parse stream and search for
     * EXT-X-TARGETDURATION or EXT-X-STREAM-INF tag, see
     * http://tools.ietf.org/html/draft-pantos-http-live-streaming-04#page-8 */
    while (true)
    {
        QString line = stream.readLine();
        if (line.isNull())
            break;
        LOG(VB_PLAYBACK, LOG_DEBUG, LOC +
            QString("IsHTTPLiveStreaming: %1").arg(line));
        if (line.startsWith(QLatin1String("#EXT-X-TARGETDURATION"))  ||
            line.startsWith(QLatin1String("#EXT-X-MEDIA-SEQUENCE"))  ||
            line.startsWith(QLatin1String("#EXT-X-KEY"))             ||
            line.startsWith(QLatin1String("#EXT-X-ALLOW-CACHE"))     ||
            line.startsWith(QLatin1String("#EXT-X-ENDLIST"))         ||
            line.startsWith(QLatin1String("#EXT-X-STREAM-INF"))      ||
            line.startsWith(QLatin1String("#EXT-X-DISCONTINUITY"))   ||
            line.startsWith(QLatin1String("#EXT-X-VERSION")))
        {
            return true;
        }
    }
    return false;
}
 
bool HLSRingBuffer::TestForHTTPLiveStreaming(const QString &filename)
{
    bool isHLS = false;
 
    // Do a peek on the URL to test the format
    MythMediaBuffer::AVFormatInitNetwork();
 
    AVIOContext* context = nullptr;
    int ret = avio_open(&context, filename.toLatin1().constData(), AVIO_FLAG_READ);
    if (ret >= 0)
    {
        std::array<uint8_t,1024> buffer {};
        ret = avio_read(context, buffer.data(), buffer.size());
        if (ret > 0)
        {
            QByteArray ba((const char*)buffer.data(), ret);
            isHLS = IsHTTPLiveStreaming(&ba);
        }
        avio_closep(&context);
    }
    else
    {
        // couldn't peek, rely on URL analysis
        QUrl url { filename };
        isHLS =
        url.path().endsWith(QLatin1String("m3u8"), Qt::CaseInsensitive) ||
        url.query( QUrl::FullyEncoded ).contains(QLatin1String("m3u8"), Qt::CaseInsensitive);
    }
    return isHLS;
}
 
/* Parsing */
QString HLSRingBuffer::ParseAttributes(const QString &line, const char *attr)
{
    int p = line.indexOf(QLatin1String(":"));
    if (p < 0)
        return {};
 
    QStringList list = line.mid(p+1).split(',');
    for (const auto& it : std::as_const(list))
    {
        QString arg = it.trimmed();
        if (arg.startsWith(attr))
        {
            int pos = arg.indexOf(QLatin1String("="));
            if (pos < 0)
                continue;
            return arg.mid(pos+1);
        }
    }
    return {};
}
 
int HLSRingBuffer::ParseDecimalValue(const QString &line, int &target)
{
    int p = line.indexOf(QLatin1String(":"));
    if (p < 0)
        return RET_ERROR;
    int i = p + 1;
    for ( ; i < line.size(); i++)
        if (!line[i].isNumber())
            break;
    if (i == p + 1)
        return RET_ERROR;
#if QT_VERSION < QT_VERSION_CHECK(6,0,0)
    target = line.midRef(p+1, i - p - 1).toInt();
#else
    target = QStringView(line).mid(p+1, i - p - 1).toInt();
#endif
    return RET_OK;
}
 
int HLSRingBuffer::ParseSegmentInformation(const HLSStream *hls, const QString &line,
                                           int &duration, QString &title)
{
    /*
     * #EXTINF:<duration>,<title>
     *
     * "duration" is an integer that specifies the duration of the media
     * file in seconds.  Durations SHOULD be rounded to the nearest integer.
     * The remainder of the line following the comma is the title of the
     * media file, which is an optional human-readable informative title of
     * the media segment
     */
    int p = line.indexOf(QLatin1String(":"));
    if (p < 0)
        return RET_ERROR;
 
    QStringList list = line.mid(p+1).split(',');
 
    /* read duration */
    if (list.isEmpty())
    {
        return RET_ERROR;
    }
    const QString& val = list[0];
 
    if (hls->Version() < 3)
    {
        bool ok = false;
        duration = val.toInt(&ok);
        if (!ok)
        {
            duration = -1;
            return RET_ERROR;
        }
    }
    else
    {
        bool ok = false;
        double d = val.toDouble(&ok);
        if (!ok)
        {
            duration = -1;
            return RET_ERROR;
        }
        if (d - ((int)d) >= 0.5)
            duration = ((int)d) + 1;
        else
            duration = ((int)d);
    }
 
    if (list.size() >= 2)
    {
        title = list[1];
    }
 
    /* Ignore the rest of the line */
    return RET_OK;
}
 
int HLSRingBuffer::ParseTargetDuration(HLSStream *hls, const QString &line)
{
    /*
     * #EXT-X-TARGETDURATION:<s>
     *
     * where s is an integer indicating the target duration in seconds.
     */
    int duration = -1;
 
    if (ParseDecimalValue(line, duration) != RET_OK)
    {
        LOG(VB_PLAYBACK, LOG_ERR, LOC + "expected #EXT-X-TARGETDURATION:<s>");
        return RET_ERROR;
    }
    hls->SetTargetDuration(std::chrono::seconds(duration));
    return RET_OK;
}
 
HLSStream *HLSRingBuffer::ParseStreamInformation(const QString &line, const QString &uri) const
{
    /*
     * #EXT-X-STREAM-INF:[attribute=value][,attribute=value]*
     *  <URI>
     */
    int id = 0;
    QString attr;
 
    attr = ParseAttributes(line, "PROGRAM-ID");
    if (attr.isNull())
    {
        LOG(VB_PLAYBACK, LOG_INFO, LOC + "#EXT-X-STREAM-INF: expected PROGRAM-ID=<value>, using -1");
        id = -1;
    }
    else
    {
        id = attr.toInt();
    }
 
    attr = ParseAttributes(line, "BANDWIDTH");
    if (attr.isNull())
    {
        LOG(VB_PLAYBACK, LOG_ERR, LOC + "#EXT-X-STREAM-INF: expected BANDWIDTH=<value>");
        return nullptr;
    }
    uint64_t bw = attr.toInt();
 
    if (bw == 0)
    {
        LOG(VB_PLAYBACK, LOG_ERR, LOC + "#EXT-X-STREAM-INF: bandwidth cannot be 0");
        return nullptr;
    }
 
    LOG(VB_PLAYBACK, LOG_INFO, LOC +
        QString("bandwidth adaptation detected (program-id=%1, bandwidth=%2")
        .arg(id).arg(bw));
 
    QString psz_uri = relative_URI(m_m3u8, uri);
 
    return new HLSStream(id, bw, psz_uri);
}
 
int HLSRingBuffer::ParseMediaSequence(HLSStream *hls, const QString &line)
{
    /*
     * #EXT-X-MEDIA-SEQUENCE:<number>
     *
     * A Playlist file MUST NOT contain more than one EXT-X-MEDIA-SEQUENCE
     * tag.  If the Playlist file does not contain an EXT-X-MEDIA-SEQUENCE
     * tag then the sequence number of the first URI in the playlist SHALL
     * be considered to be 0.
     */
    int sequence = 0;
 
    if (ParseDecimalValue(line, sequence) != RET_OK)
    {
        LOG(VB_PLAYBACK, LOG_ERR, LOC + "expected #EXT-X-MEDIA-SEQUENCE:<s>");
        return RET_ERROR;
    }
 
    if (hls->StartSequence() > 0 && !hls->Live())
    {
        LOG(VB_PLAYBACK, LOG_ERR, LOC +
            QString("EXT-X-MEDIA-SEQUENCE already present in playlist (new=%1, old=%2)")
            .arg(sequence).arg(hls->StartSequence()));
    }
    hls->SetStartSequence(sequence);
    return RET_OK;
}
 
 
int HLSRingBuffer::ParseKey(HLSStream *hls, const QString &line)
{
    /*
     * #EXT-X-KEY:METHOD=<method>[,URI="<URI>"][,IV=<IV>]
     *
     * The METHOD attribute specifies the encryption method.  Two encryption
     * methods are defined: NONE and AES-128.
     */
    int err = 0;
    QString attr = ParseAttributes(line, "METHOD");
    if (attr.isNull())
    {
        LOG(VB_PLAYBACK, LOG_ERR, LOC + "#EXT-X-KEY: expected METHOD=<value>");
        return RET_ERROR;
    }
 
    if (attr.startsWith(QLatin1String("NONE")))
    {
        QString uri = ParseAttributes(line, "URI");
        if (!uri.isNull())
        {
            LOG(VB_PLAYBACK, LOG_ERR, LOC + "#EXT-X-KEY: URI not expected");
            err = RET_ERROR;
        }
        /* IV is only supported in version 2 and above */
        if (hls->Version() >= 2)
        {
            QString iv = ParseAttributes(line, "IV");
            if (!iv.isNull())
            {
                LOG(VB_PLAYBACK, LOG_ERR, LOC + "#EXT-X-KEY: IV not expected");
                err = RET_ERROR;
            }
        }
    }
#if CONFIG_LIBCRYPTO
    else if (attr.startsWith(QLatin1String("AES-128")))
    {
        QString uri;
        QString iv;
        if (!m_aesmsg)
        {
            LOG(VB_PLAYBACK, LOG_INFO, LOC +
                "playback of AES-128 encrypted HTTP Live media detected.");
            m_aesmsg = true;
        }
        uri = ParseAttributes(line, "URI");
        if (uri.isNull())
        {
            LOG(VB_PLAYBACK, LOG_ERR, LOC +
                "#EXT-X-KEY: URI not found for encrypted HTTP Live media in AES-128");
            return RET_ERROR;
        }
 
        /* Url is between quotes, remove them */
        hls->SetKeyPath(decoded_URI(uri.remove(QChar(QLatin1Char('"')))));
 
        iv = ParseAttributes(line, "IV");
        if (!iv.isNull() && !hls->SetAESIV(iv))
        {
            LOG(VB_PLAYBACK, LOG_ERR, LOC + "invalid IV");
            err = RET_ERROR;
        }
    }
#endif
    else
    {
        LOG(VB_PLAYBACK, LOG_ERR, LOC +
            "invalid encryption type, only NONE "
#if CONFIG_LIBCRYPTO
            "and AES-128 are supported"
#else
            "is supported."
#endif
            );
        err = RET_ERROR;
    }
    return err;
}
 
int HLSRingBuffer::ParseProgramDateTime(HLSStream */*hls*/, const QString &line)
{
    /*
     * #EXT-X-PROGRAM-DATE-TIME:<YYYY-MM-DDThh:mm:ssZ>
     */
    LOG(VB_PLAYBACK, LOG_WARNING, LOC +
        QString("tag not supported: #EXT-X-PROGRAM-DATE-TIME %1")
        .arg(line));
    return RET_OK;
}
 
int HLSRingBuffer::ParseAllowCache(HLSStream *hls, const QString &line)
{
    /*
     * The EXT-X-ALLOW-CACHE tag indicates whether the client MAY or MUST
     * NOT cache downloaded media files for later replay.  It MAY occur
     * anywhere in the Playlist file; it MUST NOT occur more than once.  The
     * EXT-X-ALLOW-CACHE tag applies to all segments in the playlist.  Its
     * format is:
     *
     * #EXT-X-ALLOW-CACHE:<YES|NO>
     */
    int pos = line.indexOf(QLatin1String(":"));
    if (pos < 0)
        return RET_ERROR;
    QString answer = line.mid(pos+1, 3);
    if (answer.size() < 2)
    {
        LOG(VB_PLAYBACK, LOG_ERR, LOC + "#EXT-X-ALLOW-CACHE, ignoring ...");
        return RET_ERROR;
    }
    hls->SetCache(!answer.startsWith(QLatin1String("NO")));
    return RET_OK;
}
 
int HLSRingBuffer::ParseVersion(const QString &line, int &version)
{
    /*
     * The EXT-X-VERSION tag indicates the compatibility version of the
     * Playlist file.  The Playlist file, its associated media, and its
     * server MUST comply with all provisions of the most-recent version of
     * this document describing the protocol version indicated by the tag
     * value.
     *
     * Its format is:
     *
     * #EXT-X-VERSION:<n>
     */
 
    if (ParseDecimalValue(line, version) != RET_OK)
    {
        LOG(VB_PLAYBACK, LOG_ERR, LOC +
            "#EXT-X-VERSION: no protocol version found, should be version 1.");
        return RET_ERROR;
    }
 
    if (version <= 0 || version > 3)
    {
        LOG(VB_PLAYBACK, LOG_ERR, LOC +
            QString("#EXT-X-VERSION should be version 1, 2 or 3 iso %1")
            .arg(version));
        return RET_ERROR;
    }
    return RET_OK;
}
 
int HLSRingBuffer::ParseEndList(HLSStream *hls)
{
    /*
     * The EXT-X-ENDLIST tag indicates that no more media files will be
     * added to the Playlist file.  It MAY occur anywhere in the Playlist
     * file; it MUST NOT occur more than once.  Its format is:
     */
    hls->SetLive(false);
    LOG(VB_PLAYBACK, LOG_INFO, LOC + "video on demand (vod) mode");
    return RET_OK;
}
 
int HLSRingBuffer::ParseDiscontinuity(HLSStream */*hls*/, const QString &line)
{
    /* Not handled, never seen so far */
    LOG(VB_PLAYBACK, LOG_DEBUG, LOC + QString("#EXT-X-DISCONTINUITY %1").arg(line));
    return RET_OK;
}
 
int HLSRingBuffer::ParseM3U8(const QByteArray *buffer, StreamsList *streams)
{
    if (streams == nullptr)
    {
        streams = &m_streams;
    }
    QTextStream stream(*buffer);
#if QT_VERSION < QT_VERSION_CHECK(6,0,0)
    stream.setCodec("UTF-8");
#else
    stream.setEncoding(QStringConverter::Utf8);
#endif
 
    QString line = stream.readLine();
    if (line.isNull())
        return RET_ERROR;
 
    if (!line.startsWith(QLatin1String("#EXTM3U")))
    {
        LOG(VB_PLAYBACK, LOG_ERR, LOC + "missing #EXTM3U tag .. aborting");
        return RET_ERROR;
    }
 
    /* What is the version ? */
    int version = 1;
    int p = buffer->indexOf("#EXT-X-VERSION:");
    if (p >= 0)
    {
        stream.seek(p);
        QString psz_version = stream.readLine();
        if (psz_version.isNull())
            return RET_ERROR;
        int ret = ParseVersion(psz_version, version);
        if (ret != RET_OK)
        {
            LOG(VB_GENERAL, LOG_WARNING, LOC +
                "#EXT-X-VERSION: no protocol version found, assuming version 1.");
            version = 1;
        }
    }
 
    /* Is it a meta index file ? */
    bool meta = buffer->indexOf("#EXT-X-STREAM-INF") >= 0;
 
    int err = RET_OK;
 
    if (meta)
    {
        LOG(VB_PLAYBACK, LOG_INFO, LOC + "Meta playlist");
 
        /* M3U8 Meta Index file */
        stream.seek(0); // rewind
        while (!m_killed)
        {
            line = stream.readLine();
            if (line.isNull())
                break;
 
            if (line.startsWith(QLatin1String("#EXT-X-STREAM-INF")))
            {
                m_meta = true;
                QString uri = stream.readLine();
                if (uri.isNull())
                {
                    err = RET_ERROR;
                    break;
                }
                if (uri.startsWith(QLatin1String("#")))
                {
                    LOG(VB_GENERAL, LOG_INFO, LOC +
                        QString("Skipping invalid stream-inf: %1")
                        .arg(uri));
                }
                else
                {
                    HLSStream *hls = ParseStreamInformation(line, decoded_URI(uri));
                    if (hls)
                    {
                        /* Download playlist file from server */
                        QByteArray buf;
                        bool ret = downloadURL(hls->Url(), &buf);
                        if (!ret)
                        {
                            LOG(VB_GENERAL, LOG_INFO, LOC +
                                QString("Skipping invalid stream, couldn't download: %1")
                                .arg(hls->Url()));
                            delete hls;
                            continue;
                        }
                        streams->append(hls);
                        // One last chance to abort early
                        if (m_killed)
                        {
                            err = RET_ERROR;
                            break;
                        }
                        /* Parse HLS m3u8 content. */
                        err = ParseM3U8(&buf, streams);
                        if (err != RET_OK)
                            break;
                        hls->SetVersion(version);
                    }
                }
            }
        }
    }
    else
    {
        HLSStream *hls = nullptr;
        if (m_meta)
        {
            hls = GetLastStream(streams);
        }
        else
        {
            /* No Meta playlist used */
            hls = new HLSStream(0, 0, m_m3u8);
            streams->append(hls);
            /* Get TARGET-DURATION first */
            p = buffer->indexOf("#EXT-X-TARGETDURATION:");
            if (p >= 0)
            {
                stream.seek(p);
                QString psz_duration = stream.readLine();
                if (psz_duration.isNull())
                    return RET_ERROR;
                err = ParseTargetDuration(hls, psz_duration);
                if (err != RET_OK)
                    return err;
            }
            /* Store version */
            hls->SetVersion(version);
        }
        LOG(VB_PLAYBACK, LOG_INFO, LOC +
            QString("%1 Playlist HLS protocol version: %2")
            .arg(hls->Live() ? "Live": "VOD").arg(version));
 
        // rewind
        stream.seek(0);
        /* */
        std::chrono::seconds segment_duration = -1s;
        QString title;
        while (err == RET_OK)
        {
            /* Next line */
            line = stream.readLine();
            if (line.isNull())
                break;
            LOG(VB_PLAYBACK, LOG_DEBUG, LOC + QString("ParseM3U8: %1")
                .arg(line));
 
            if (line.startsWith(QLatin1String("#EXTINF")))
            {
                int tmp = -1;
                err = ParseSegmentInformation(hls, line, tmp, title);
                segment_duration = std::chrono::seconds(tmp);
            }
            else if (line.startsWith(QLatin1String("#EXT-X-TARGETDURATION")))
            {
                err = ParseTargetDuration(hls, line);
            }
            else if (line.startsWith(QLatin1String("#EXT-X-MEDIA-SEQUENCE")))
            {
                err = ParseMediaSequence(hls, line);
            }
            else if (line.startsWith(QLatin1String("#EXT-X-KEY")))
            {
                err = ParseKey(hls, line);
            }
            else if (line.startsWith(QLatin1String("#EXT-X-PROGRAM-DATE-TIME")))
            {
                err = ParseProgramDateTime(hls, line);
            }
            else if (line.startsWith(QLatin1String("#EXT-X-ALLOW-CACHE")))
            {
                err = ParseAllowCache(hls, line);
            }
            else if (line.startsWith(QLatin1String("#EXT-X-DISCONTINUITY")))
            {
                err = ParseDiscontinuity(hls, line);
            }
            else if (line.startsWith(QLatin1String("#EXT-X-VERSION")))
            {
                int version2 = 0;
                err = ParseVersion(line, version2);
                hls->SetVersion(version2);
            }
            else if (line.startsWith(QLatin1String("#EXT-X-ENDLIST")))
            {
                err = ParseEndList(hls);
            }
            else if (!line.startsWith(QLatin1String("#")) && !line.isEmpty())
            {
                hls->AddSegment(segment_duration, title, decoded_URI(line));
                segment_duration = -1s; /* reset duration */
                title = "";
            }
        }
    }
    return err;
}
 
// stream content functions
int HLSRingBuffer::Prefetch(int count)
{
    int retries = 0;
    std::chrono::microseconds starttime = mdate();
    LOG(VB_PLAYBACK, LOG_INFO, LOC +
        QString("Starting Prefetch for %2 segments")
        .arg(count));
    m_streamworker->Lock();
    m_streamworker->Wakeup();
    while (!m_error && !m_killed && (retries < 20) &&
           (m_streamworker->CurrentPlaybackBuffer(false) < count) &&
           !m_streamworker->IsAtEnd())
    {
        m_streamworker->WaitForSignal();
        retries++;
    }
    m_streamworker->Unlock();
    LOG(VB_PLAYBACK, LOG_INFO, LOC + QString("Finished Prefetch (%1s)")
        .arg(duration_cast<std::chrono::seconds>(mdate() - starttime).count()));
    // we waited more than 10s abort
    if (retries >= 10)
        return RET_ERROR;
    return RET_OK;
}
 
void HLSRingBuffer::SanityCheck(const HLSStream *hls) const
{
    bool live = hls->Live();
    /* sanity check */
    if ((m_streamworker->CurrentPlaybackBuffer() == 0) &&
        (!m_streamworker->IsAtEnd(true) || live))
    {
        LOG(VB_PLAYBACK, LOG_WARNING, LOC + "playback will stall");
    }
    else if ((m_streamworker->CurrentPlaybackBuffer() < PLAYBACK_MINBUFFER) &&
             (!m_streamworker->IsAtEnd(true) || live))
    {
        LOG(VB_PLAYBACK, LOG_WARNING, LOC + "playback in danger of stalling");
    }
    else if (live && m_streamworker->IsAtEnd(true) &&
             (m_streamworker->CurrentPlaybackBuffer() < PLAYBACK_MINBUFFER))
    {
        LOG(VB_PLAYBACK, LOG_WARNING, LOC + "playback will exit soon, starving for data");
    }
}
 
HLSSegment *HLSRingBuffer::GetSegment(int segnum, std::chrono::milliseconds timeout)
{
    HLSSegment *segment = nullptr;
    int stream = m_streamworker->StreamForSegment(segnum);
    if (stream < 0)
    {
        // we haven't downloaded that segment, request it
        // we should never be into this condition for normal playback
        m_streamworker->Seek(segnum);
        m_streamworker->Lock();
        /* Wait for download to be finished */
        LOG(VB_PLAYBACK, LOG_WARNING, LOC +
            LOC + QString("waiting to get segment %1")
            .arg(segnum));
        int retries = 0;
        while (!m_error && (stream < 0) && (retries < 10))
        {
            m_streamworker->WaitForSignal(timeout);
            stream = m_streamworker->StreamForSegment(segnum, false);
            retries++;
        }
        m_streamworker->Unlock();
        if (stream < 0)
            return nullptr;
    }
    HLSStream *hls = GetStream(stream);
    hls->Lock();
    segment = hls->GetSegment(segnum);
    hls->Unlock();
    LOG(VB_PLAYBACK, LOG_DEBUG, LOC +
        QString("GetSegment %1 [%2] stream[%3] (bitrate:%4)")
        .arg(segnum).arg(segment->Id()).arg(stream).arg(hls->Bitrate()));
    SanityCheck(hls);
    return segment;
}
 
int HLSRingBuffer::NumStreams(void) const
{
    return m_streams.size();
}
 
int HLSRingBuffer::NumSegments(void) const
{
    HLSStream *hls = GetStream(0);
    if (hls == nullptr)
        return 0;
    hls->Lock();
    int count = hls->NumSegments();
    hls->Unlock();
    return count;
}
 
int HLSRingBuffer::ChooseSegment(int stream) const
{
    /* Choose a segment to start which is no closer than
     * 3 times the target duration from the end of the playlist.
     */
    int wanted          = 0;
    int segid           = 0;
    std::chrono::seconds wanted_duration = 0s;
    int count           = NumSegments();
    int i               = count - 1;
 
    HLSStream *hls = GetStream(stream);
    while(i >= 0)
    {
        HLSSegment *segment = hls->GetSegment(i);
        if (segment == nullptr)
            continue;
 
        if (segment->Duration() > hls->TargetDuration())
        {
            LOG(VB_PLAYBACK, LOG_WARNING, LOC +
                QString("EXTINF:%1 duration is larger than EXT-X-TARGETDURATION:%2")
                .arg(segment->Duration().count()).arg(hls->TargetDuration().count()));
        }
 
        wanted_duration += segment->Duration();
        if (wanted_duration >= 3 * hls->TargetDuration())
        {
            /* Start point found */
            wanted   = i;
            segid    = segment->Id();
            break;
        }
        i-- ;
    }
 
    LOG(VB_PLAYBACK, LOG_DEBUG, LOC +
        QString("Choose segment %1/%2 [%3]")
        .arg(wanted).arg(count).arg(segid));
    return wanted;
}
 
void HLSRingBuffer::SanitizeStreams(StreamsList *streams)
{
    // no lock is required as, at this stage, no threads have either been started
    // or we are working on a stream list unique to PlaylistWorker
    if (streams == nullptr)
    {
        streams = &m_streams;
    }
    QMap<int,int> idstart;
    // Find the highest starting sequence for each stream
    for (int n = streams->size() - 1 ; n >= 0; n--)
    {
        HLSStream *hls = GetStream(n, streams);
        if (hls == nullptr)
            continue;
        if (hls->NumSegments() == 0)
        {
            streams->removeAt(n);
            continue;   // remove it
        }
 
        int id      = hls->Id();
        int start   = hls->StartSequence();
        if (!idstart.contains(id))
        {
            idstart.insert(id, start);
        }
        int start2  = idstart.value(id);
        if (start > start2)
        {
            idstart.insert(id, start);
        }
    }
    // Find the highest starting sequence for each stream
    for (int n = 0; n < streams->size(); n++)
    {
        HLSStream *hls = GetStream(n, streams);
        if (hls == nullptr)
            continue;
        int id      = hls->Id();
        int seq     = hls->StartSequence();
        int newstart= idstart.value(id);
        int todrop  = newstart - seq;
        if (todrop == 0)
        {
            // perfect, leave it alone
            continue;
        }
        if (todrop >= hls->NumSegments() || todrop < 0)
        {
            LOG(VB_PLAYBACK, LOG_ERR, LOC +
                QString("stream %1 [id=%2] can't be properly adjusted, ignoring")
                .arg(n).arg(hls->Id()));
            continue;
        }
        for (int i = 0; i < todrop; i++)
        {
            hls->RemoveSegment(0);
        }
        hls->SetStartSequence(newstart);
    }
}
 
bool HLSRingBuffer::OpenFile(const QString &lfilename, std::chrono::milliseconds /*retry_ms*/)
{
    QWriteLocker lock(&m_rwLock);
 
    m_safeFilename = lfilename;
    m_filename = lfilename;
    QString finalURL;
 
    QByteArray buffer;
    if (!downloadURL(m_filename, &buffer, finalURL))
    {
        LOG(VB_PLAYBACK, LOG_ERR, LOC +
            QString("Couldn't open URL %1").arg(m_filename));
        return false;   // can't download file
    }
    if (m_filename != finalURL)
    {
        LOG(VB_PLAYBACK, LOG_INFO, LOC +
            QString("Redirected %1 -> %2 ").arg(m_filename, finalURL));
        m_filename = finalURL;
    }
    if (!IsHTTPLiveStreaming(&buffer))
    {
        LOG(VB_PLAYBACK, LOG_ERR, LOC +
            QString("%1 isn't a HTTP Live Streaming URL").arg(m_filename));
        return false;
    }
    // let's go
    m_m3u8 = m_filename;
    LOG(VB_PLAYBACK, LOG_INFO, LOC + QString("HTTP Live Streaming (%1)")
        .arg(m_m3u8));
 
    /* Parse HLS m3u8 content. */
    if (ParseM3U8(&buffer, &m_streams) != RET_OK || m_streams.isEmpty())
    {
        LOG(VB_PLAYBACK, LOG_ERR, LOC +
            QString("An error occurred reading M3U8 playlist (%1)").arg(m_filename));
        m_error = true;
        return false;
    }
 
    SanitizeStreams();
 
    /* HLS standard doesn't provide any guaranty about streams
     being sorted by bitrate, so we sort them, higher bitrate being first */
    // QList doesn't play well with std::ranges
    // NOLINTNEXTLINE(modernize-use-ranges)
    std::sort(m_streams.begin(), m_streams.end(), HLSStream::IsGreater);
 
    // if we want as close to live. We should be selecting a further segment
    // m_live ? ChooseSegment(0) : 0;
//    if (m_live && m_startup < 0)
//    {
//        LOG(VB_PLAYBACK, LOG_WARNING, LOC +
//            "less data than 3 times 'target duration' available for "
//            "live playback, playback may stall");
//        m_startup = 0;
//    }
    m_startup = 0;
    m_playback->SetSegment(m_startup);
 
    m_streamworker = new StreamWorker(this, m_startup, PLAYBACK_READAHEAD);
    m_streamworker->start();
 
    if (Prefetch(std::min(NumSegments(), PLAYBACK_MINBUFFER)) != RET_OK)
    {
        LOG(VB_PLAYBACK, LOG_ERR, LOC +
            "fetching first segment failed or didn't complete within 10s.");
        m_error = true;
        return false;
    }
 
    // set bitrate value used to calculate the size of the stream
    HLSStream *hls  = GetCurrentStream();
    m_bitrate       = hls->Bitrate();
 
    // Set initial seek position (relative to m_startup)
    m_playback->SetOffset(0);
 
    /* Initialize HLS live stream thread */
    //if (m_live)   // commented out as some streams are marked as VOD, yet
    // aren't, they are updated over time
    {
        m_playlistworker = new PlaylistWorker(this, 0ms);
        m_playlistworker->start();
    }
 
    return true;
}
 
bool HLSRingBuffer::SaveToDisk(const QString &filename, int segstart, int segend)
{
    // download it all
    FILE *fp = fopen(filename.toLatin1().constData(), "w");
    if (fp == nullptr)
        return false;
    int count = NumSegments();
    if (segend < 0)
    {
        segend = count;
    }
    for (int i = segstart; i < segend; i++)
    {
        HLSSegment *segment = GetSegment(i);
        if (segment == nullptr)
        {
            LOG(VB_PLAYBACK, LOG_ERR, LOC +
                QString("downloading %1 failed").arg(i));
        }
        else
        {
            LOG(VB_PLAYBACK, LOG_INFO, LOC +
                QString("download of %1 succeeded")
                .arg(i));
            fwrite(segment->Data(), segment->Size(), 1, fp);
            fflush(fp);
        }
    }
    fclose(fp);
    return true;
}
 
int64_t HLSRingBuffer::SizeMedia(void) const
{
    if (m_error)
        return -1;
 
    HLSStream *hls = GetCurrentStream();
    if (nullptr == hls)
        return -1;
    int64_t size = hls->Duration().count() * m_bitrate / 8;
 
    return size;
}
 
void HLSRingBuffer::WaitUntilBuffered(void)
{
    HLSStream *hls = GetCurrentStream();
    bool live = hls ? hls->Live() : false;
 
    // last seek was to end of media, we are just in seek mode so do not wait
    if (m_seektoend)
        return;
 
    if (m_streamworker->GotBufferedSegments(m_playback->Segment(), 2) ||
        (!live && m_streamworker->IsAtEnd()))
    {
        return;
    }
 
    // danger of getting to the end... pause until we have some more
    LOG(VB_PLAYBACK, LOG_INFO, LOC +
        QString("pausing until we get sufficient data buffered"));
    m_streamworker->Wakeup();
    m_streamworker->Lock();
    while (!m_error && !m_interrupted &&
           (m_streamworker->CurrentPlaybackBuffer(false) < 2) &&
           (live || !m_streamworker->IsAtEnd()))
    {
        m_streamworker->WaitForSignal(1s);
    }
    m_streamworker->Unlock();
}
 
int HLSRingBuffer::SafeRead(void *data, uint sz)
{
    if (m_error)
        return -1;
 
    int used = 0;
    int i_read = sz;
 
    WaitUntilBuffered();
    if (m_interrupted)
    {
        LOG(VB_PLAYBACK, LOG_DEBUG, LOC + QString("interrupted"));
        return 0;
    }
 
    while (i_read > 0 && !m_interrupted)
    {
        int segnum = m_playback->Segment();
        if (segnum >= NumSegments())
        {
            m_playback->AddOffset(used);
            return used;
        }
        int stream = m_streamworker->StreamForSegment(segnum);
        if (stream < 0)
        {
            // we haven't downloaded this segment yet, likely that it was
            // dropped (livetv?)
            m_playback->IncrSegment();
            continue;
        }
        HLSStream *hls = GetStream(stream);
        if (hls == nullptr)
            break;
        HLSSegment *segment = hls->GetSegment(segnum);
        if (segment == nullptr)
            break;
 
        segment->Lock();
        if (segment->SizePlayed() == segment->Size())
        {
            if (!hls->Cache() || hls->Live())
            {
                segment->Clear();
                m_streamworker->RemoveSegmentFromStream(segnum);
            }
            else
            {
                segment->Reset();
            }
 
            m_playback->IncrSegment();
            segment->Unlock();
 
            /* signal download thread we're about to use a new segment */
            m_streamworker->Wakeup();
            continue;
        }
 
        if (segment->SizePlayed() == 0)
        {
            LOG(VB_PLAYBACK, LOG_INFO, LOC +
                QString("started reading segment %1 [id:%2] from stream %3 (%4 buffered)")
                .arg(segnum).arg(segment->Id()).arg(stream)
                .arg(m_streamworker->CurrentPlaybackBuffer()));
        }
 
        int32_t len = segment->Read((uint8_t*)data + used, i_read, m_fd);
        used    += len;
        i_read  -= len;
        segment->Unlock();
    }
 
    if (m_interrupted)
        LOG(VB_PLAYBACK, LOG_DEBUG, LOC + QString("interrupted"));
 
    m_playback->AddOffset(used);
    return used;
}
 
int HLSRingBuffer::DurationForBytes(uint size)
{
    int segnum = m_playback->Segment();
    int stream = m_streamworker->StreamForSegment(segnum);
    if (stream < 0)
    {
        return 0;
    }
    HLSStream *hls = GetStream(stream);
    if (hls == nullptr)
    {
        return 0;
    }
    HLSSegment *segment = hls->GetSegment(segnum);
    if (segment == nullptr)
    {
        return 0;
    }
    auto byterate = (uint64_t)(((double)segment->Size()) /
                               ((double)segment->Duration().count()));
 
    return (int)((size * 1000.0) / byterate);
}
 
long long HLSRingBuffer::GetRealFileSizeInternal(void) const
{
    QReadLocker lock(&m_rwLock);
    return SizeMedia();
}
 
long long HLSRingBuffer::SeekInternal(long long pos, int whence)
{
    if (m_error)
        return -1;
 
    if (!IsSeekingAllowed())
    {
        return m_playback->Offset();
    }
 
    std::chrono::microseconds starting = mdate();
 
    QWriteLocker lock(&m_posLock);
 
    int totalsize = SizeMedia();
    int64_t where = 0;
    switch (whence)
    {
        case SEEK_CUR:
            // return current location, nothing to do
            if (pos == 0)
            {
                return m_playback->Offset();
            }
            where = m_playback->Offset() + pos;
            break;
        case SEEK_END:
            where = SizeMedia() - pos;
            break;
        case SEEK_SET:
        default:
            where = pos;
            break;
    }
 
    // We determine the duration at which it was really attempting to seek to
    auto postime    = secondsFromFloat((where * 8.0) / m_bitrate);
    int count       = NumSegments();
    int segnum      = m_playback->Segment();
    HLSStream  *hls = GetStreamForSegment(segnum);
 
    /* restore current segment's file position indicator to 0 */
    HLSSegment *segment = hls->GetSegment(segnum);
    if (segment != nullptr)
    {
        segment->Lock();
        segment->Reset();
        segment->Unlock();
    }
 
    if (where > totalsize)
    {
        // we're at the end, never let seek after last 3 segments
        postime -= hls->TargetDuration() * 3;
        if (postime < 0s)
        {
            postime = 0s;
        }
    }
 
    // Find segment containing position
    std::chrono::seconds starttime   = 0s;
    std::chrono::seconds endtime     = 0s;
    for (int n = m_startup; n < count; n++)
    {
        hls = GetStreamForSegment(n);
        if (hls == nullptr)
        {
            // error, should never happen, irrecoverable error
            return -1;
        }
        segment = hls->GetSegment(n);
        if (segment == nullptr)
        {
            // stream doesn't contain segment error can't continue,
            // unknown error
            return -1;
        }
        endtime += segment->Duration();
        if (postime < endtime)
        {
            segnum = n;
            break;
        }
        starttime = endtime;
    }
 
    /*
     * Live Mode exception:
     * FFmpeg seek to the last segment in order to determine the size of the video
     * so do not allow seeking to the last segment if in live mode as we don't care
     * about the size
     * Also do not allow to seek before the current playback segment as segment
     * has been cleared from memory
     * We only let determine the size if the bandwidth would allow fetching the
     * the segments in less than 5s
     */
    if (hls->Live() && (segnum >= count - 1 || segnum < m_playback->Segment()) &&
        ((hls->TargetDuration() * hls->Bitrate() / m_streamworker->Bandwidth()) > 5s))
    {
        return m_playback->Offset();
    }
    m_seektoend = segnum >= count - 1;
 
    m_playback->SetSegment(segnum);
 
    m_streamworker->Seek(segnum);
    m_playback->SetOffset(postime.count() * m_bitrate / 8);
 
    m_streamworker->Lock();
 
    /* Wait for download to be finished and to buffer 3 segment */
    LOG(VB_PLAYBACK, LOG_INFO, LOC +
        QString("seek to segment %1").arg(segnum));
 
    // see if we've already got the segment, and at least 2 buffered after
    // then no need to wait for streamworker
    while (!m_error && !m_interrupted &&
           (!m_streamworker->GotBufferedSegments(segnum, 2) &&
            (m_streamworker->CurrentPlaybackBuffer(false) < 2) &&
            !m_streamworker->IsAtEnd()))
    {
        m_streamworker->WaitForSignal(1s);
    }
    if (m_interrupted)
        LOG(VB_PLAYBACK, LOG_DEBUG, LOC + QString("interrupted"));
 
    m_streamworker->Unlock();
 
    // now seek within found segment
    int stream = m_streamworker->StreamForSegment(segnum);
    if (stream < 0)
    {
        // segment didn't get downloaded (timeout?)
        LOG(VB_PLAYBACK, LOG_ERR, LOC +
            QString("seek error: segment %1 should have been downloaded, but didn't."
                    " Playback will stall")
            .arg(segnum));
    }
    else
    {
        if (segment == nullptr) // can never happen, make coverity happy
        {
            // stream doesn't contain segment error can't continue,
            // unknown error
            return -1;
        }
        int32_t skip = ((postime - starttime) * segment->Size()) / segment->Duration();
        segment->Read(nullptr, skip);
    }
    LOG(VB_PLAYBACK, LOG_INFO, LOC + QString("seek completed in %1s")
        .arg(duration_cast<std::chrono::seconds>(mdate() - starting).count()));
 
    return m_playback->Offset();
}
 
long long HLSRingBuffer::GetReadPosition(void) const
{
    if (m_error)
        return 0;
    return m_playback->Offset();
}
 
bool HLSRingBuffer::IsOpen(void) const
{
    return !m_error && !m_streams.isEmpty() && NumSegments() > 0;
}
 
void HLSRingBuffer::Interrupt(void)
{
    QMutexLocker lock(&m_lock);
 
    // segment didn't get downloaded (timeout?)
    LOG(VB_PLAYBACK, LOG_DEBUG, LOC + QString("requesting interrupt"));
    m_interrupted = true;
}
 
void HLSRingBuffer::Continue(void)
{
    QMutexLocker lock(&m_lock);
 
    // segment didn't get downloaded (timeout?)
    LOG(VB_PLAYBACK, LOG_DEBUG, LOC + QString("requesting restart"));
    m_interrupted = false;
}