doxygen/mythmediabuffer_8h_source.html

#ifndef MYTHMEDIABUFFER_H

#define MYTHMEDIABUFFER_H


// Qt

#include <QReadWriteLock>

#include <QWaitCondition>

#include <QString>

#include <QMutex>

#include <QMap>


// MythTV

#include "libmythbase/mythconfig.h"

#include "libmythtv/mythtvexp.h"

#include "libmythbase/mthread.h"

#include "libmythbase/mythchrono.h"


// FFmpeg

extern "C" {

#include "libavcodec/avcodec.h"

}


// Size of PNG header plus one empty chunk

static constexpr qint64 kReadTestSize { 20 };


// about one second at 35Mb

static constexpr uint32_t BUFFER_SIZE_MINIMUM    { 4 * 1024 * 1024 };

static constexpr uint8_t  BUFFER_FACTOR_NETWORK  { 2 };

static constexpr uint8_t  BUFFER_FACTOR_BITRATE  { 2 };

static constexpr uint8_t  BUFFER_FACTOR_MATROSKA { 2 };


static constexpr int32_t  DEFAULT_CHUNK_SIZE     { 32768 };


static inline QString seek2string(int Whence)

{

    if (SEEK_SET == Whence)

        return "SEEK_SET";

    if (SEEK_CUR == Whence)

        return "SEEK_CUR";

    return "SEEK_END";

}


class ThreadedFileWriter;

class MythDVDBuffer;

class MythBDBuffer;

class LiveTVChain;

class RemoteFile;


enum MythBufferType : std::uint8_t

{

    kMythBufferUnknown = 0,

    kMythBufferFile,

    kMythBufferDVD,

    kMythBufferBD,

    kMythBufferHTTP,

    kMythBufferHLS,

    kMythBufferMHEG

};


class MTV_PUBLIC MythMediaBuffer : protected MThread

{

    friend class MythInteractiveBuffer;


  public:

    static MythMediaBuffer *Create(const QString &Filename, bool Write,

                                   bool UseReadAhead = true,

                                   std::chrono::milliseconds Timeout = kDefaultOpenTimeout,

                                   bool StreamOnly = false);

    ~MythMediaBuffer() override = 0;

    MythBufferType GetType() const;


    static constexpr std::chrono::milliseconds kDefaultOpenTimeout {  2s };

    static constexpr std::chrono::milliseconds kLiveTVOpenTimeout  { 10s };

    static QString   BitrateToString     (uint64_t Rate, bool Hz = false);

    static void      AVFormatInitNetwork (void);


    void      SetOldFile           (bool Old);

    void      UpdateRawBitrate     (uint RawBitrate);

    void      UpdatePlaySpeed      (float PlaySpeed);

    void      EnableBitrateMonitor (bool Enable);

    void      SetBufferSizeFactors (bool EstBitrate, bool Matroska);

    void      SetWaitForWrite      (void);

    QString   GetSafeFilename      (void);

    QString   GetFilename          (void) const;

    QString   GetSubtitleFilename  (void) const;

    QString   GetLastError         (void) const;

    bool      GetCommsError        (void) const;

    void      ResetCommsError      (void);

    bool      GetStopReads         (void) const;

    QString   GetDecoderRate       (void);

    QString   GetStorageRate       (void);

    QString   GetAvailableBuffer   (void);

    uint      GetBufferSize        (void) const;

    bool      IsNearEnd            (double Framerate, uint Frames) const;

    long long GetWritePosition     (void) const;

    long long GetRealFileSize      (void) const;

    bool      IsDisc               (void) const;

    bool      IsDVD                (void) const;

    bool      IsBD                 (void) const;

    const MythDVDBuffer *DVD       (void) const;

    MythDVDBuffer       *DVD       (void);

    const MythBDBuffer  *BD        (void) const;

    MythBDBuffer        *BD        (void);

    int       Read                 (void *Buffer, int Count);

    int       Peek                 (void *Buffer, int Count);

    int       Peek                 (std::vector<char>& Buffer);

    void      Reset                (bool Full = false, bool ToAdjust = false, bool ResetInternal = false);

    void      Pause                (void);

    void      Unpause              (void);

    void      WaitForPause         (void);

    void      Start                (void);

    void      StopReads            (void);

    void      StartReads           (void);

    long long Seek                 (long long Position, int Whence, bool HasLock = false);

    long long SetAdjustFilesize    (void);


    // LiveTV used utilities

    int       GetReadBufAvail      (void) const;

    bool      SetReadInternalMode  (bool Mode);

    bool      IsReadInternalMode   (void) const;

    bool      LiveMode             (void) const;

    void      SetLiveMode          (LiveTVChain *Chain);

    void      IgnoreLiveEOF        (bool Ignore);


    // ThreadedFileWriter proxies

    int       Write                (const void *Buffer, uint Count);

    bool      IsIOBound            (void) const;

    void      WriterFlush          (void);

    void      Sync                 (void);

    long long WriterSeek           (long long Position, int Whence, bool HasLock = false);

    bool      WriterSetBlocking    (bool Lock = true);


    virtual long long GetReadPosition   (void) const = 0;

    virtual bool      IsOpen            (void) const = 0;

    virtual bool      IsStreamed        (void) { return LiveMode(); }

    virtual bool      IsSeekingAllowed  (void) { return true; }

    virtual bool      IsBookmarkAllowed (void) { return true; }

    virtual int       BestBufferSize    (void) { return DEFAULT_CHUNK_SIZE; }

    virtual bool      StartFromBeginning(void) { return true; }

    virtual void      IgnoreWaitStates  (bool /*Ignore*/) { }

    virtual bool      IsInMenu          (void) const { return false; }

    virtual bool      IsInStillFrame    (void) const { return false; }

    virtual bool      IsInDiscMenuOrStillFrame(void) const { return IsInMenu() || IsInStillFrame(); }

    virtual bool      HandleAction      (const QStringList &/*Action*/, mpeg::chrono::pts /*Pts*/) { return false; }

    virtual bool      OpenFile          (const QString &Filename, std::chrono::milliseconds Retry = kDefaultOpenTimeout) = 0;

    virtual bool      ReOpen            (const QString& /*Filename*/ = "") { return false; }


  protected:

    explicit MythMediaBuffer(MythBufferType Type);


    void     run(void) override;

    void     CreateReadAheadBuffer (void);

    void     CalcReadAheadThresh   (void);

    bool     PauseAndWait          (void);

    int      ReadPriv              (void *Buffer, int Count, bool Peek);

    int      ReadDirect            (void *Buffer, int Count, bool Peek);

    bool     WaitForReadsAllowed   (void);

    int      WaitForAvail          (int Count, std::chrono::milliseconds Timeout);

    int      ReadBufFree           (void) const;

    int      ReadBufAvail          (void) const;

    void     ResetReadAhead        (long long NewInternal);

    void     KillReadAheadThread   (void);

    uint64_t UpdateDecoderRate     (uint64_t Latest = 0);

    uint64_t UpdateStorageRate     (uint64_t Latest = 0);


    virtual int       SafeRead     (void *Buffer, uint Size) = 0;

    virtual long long GetRealFileSizeInternal(void) const { return -1; }

    virtual long long SeekInternal (long long Position, int Whence) = 0;


  protected:

    MythBufferType         m_type;


    mutable QReadWriteLock m_posLock;

    long long              m_readPos         { 0 };

    long long              m_writePos        { 0 };

    long long              m_internalReadPos { 0 };

    long long              m_ignoreReadPos   { -1 };


    mutable QReadWriteLock m_rbrLock;

    int                    m_rbrPos          { 0 };


    mutable QReadWriteLock m_rbwLock;

    int                    m_rbwPos          { 0 };


    // note should not go under rwLock..

    // this is used to break out of read_safe where rwLock is held

    volatile bool          m_stopReads       {false};


    // unprotected (for debugging)

    QString                m_safeFilename;


    mutable QReadWriteLock m_rwLock;

    QString                m_filename;

    QString                m_subtitleFilename;

    QString                m_lastError;

    ThreadedFileWriter    *m_tfw              { nullptr };

    int                    m_fd2              { -1 };

    bool                   m_writeMode        { false   };

    RemoteFile            *m_remotefile       { nullptr };

    uint                   m_bufferSize       { BUFFER_SIZE_MINIMUM };

    bool                   m_lowBuffers       { false };

    bool                   m_fileIsMatroska   { false };

    bool                   m_unknownBitrate   { false };

    bool                   m_startReadAhead   { false };

    char                  *m_readAheadBuffer  { nullptr };

    bool                   m_readAheadRunning { false };

    bool                   m_reallyRunning    { false };

    bool                   m_requestPause     { false };

    bool                   m_paused           { false };

    bool                   m_ateof            { false };

    bool                   m_waitForWrite     { false };

    bool                   m_beingWritten     { false };

    bool                   m_readsAllowed     { false };

    bool                   m_readsDesired     { false };

    volatile bool          m_recentSeek       { true  }; // not protected by rwLock

    bool                   m_setSwitchToNext  { false };

    uint                   m_rawBitrate       { 8000  };

    float                  m_playSpeed        { 1.0F  };

    int                    m_fillThreshold    { 65536 };

    int                    m_fillMin          { -1    };

    int                    m_readBlockSize    { DEFAULT_CHUNK_SIZE};

    int                    m_wantToRead       { 0     };

    int                    m_numFailures      { 0     }; // (see note 1)

    bool                   m_commsError       { false };

    bool                   m_oldfile          { false };

    LiveTVChain           *m_liveTVChain      { nullptr };

    bool                   m_ignoreLiveEOF    { false };

    long long              m_readAdjust       { 0 };

    int                    m_readOffset       { 0 };

    bool                   m_readInternalMode { false };

    // End of section protected by rwLock


    bool                   m_bitrateMonitorEnabled { false };

    QMutex                 m_decoderReadLock;

    QMap<std::chrono::milliseconds, uint64_t> m_decoderReads;

    QMutex                 m_storageReadLock;

    QMap<std::chrono::milliseconds, uint64_t> m_storageReads;


    // note 1: numfailures is modified with only a read lock in the

    // read ahead thread, but this is safe since all other places

    // that use it are protected by a write lock. But this is a

    // fragile state of affairs and care must be taken when modifying

    // code or locking around this variable.


    QWaitCondition         m_generalWait; // protected by rwLock


  private:

    bool m_bitrateInitialized { false };

};

#endif