imagemetadata.cpp

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#include "imagemetadata.h"
 
#include <QTextStream>
 
#include "libmythbase/mythappname.h"
#include "libmythbase/mythdirs.h"         // for GetAppBinDir
#include "libmythbase/mythlogging.h"
#include "libmythbase/mythsystemlegacy.h" // for ffprobe
 
// libexiv2 for Exif metadata
#include <exiv2/exiv2.hpp>
 
// To read FFMPEG Metadata
extern "C" {
#include "libavformat/avformat.h"
}
 
// Uncomment this to log raw metadata from exif/ffmpeg
//#define DUMP_METADATA_TAGS yes
 
#define LOC QString("ImageMetaData: ")
 
 
int Orientation::Transform(int transform)
{
    m_current = Apply(transform);
    return Composite();
}
 
int Orientation::GetCurrent() const
{
    return m_current;
}
 
 
int Orientation::Apply(int transform) const
{
    if (transform == kResetToExif)
        return m_file;
 
    // https://github.com/recurser/exif-orientation-examples is a useful resource.
    switch (m_current)
    {
    case 0: // The image has no orientation info
    case 1: // The image is in its original state
        switch (transform)
        {
        case kRotateCW:       return 6;
        case kRotateCCW:      return 8;
        case kFlipHorizontal: return 2;
        case kFlipVertical:   return 4;
        }
        break;
 
    case 2: // The image is horizontally flipped
        switch (transform)
        {
        case kRotateCW:       return 7;
        case kRotateCCW:      return 5;
        case kFlipHorizontal: return 1;
        case kFlipVertical:   return 3;
        }
        break;
 
    case 3: // The image is rotated 180°
        switch (transform)
        {
        case kRotateCW:       return 8;
        case kRotateCCW:      return 6;
        case kFlipHorizontal: return 4;
        case kFlipVertical:   return 2;
        }
        break;
 
    case 4: // The image is vertically flipped
        switch (transform)
        {
        case kRotateCW:       return 5;
        case kRotateCCW:      return 7;
        case kFlipHorizontal: return 3;
        case kFlipVertical:   return 1;
        }
        break;
 
    case 5: // The image is rotated 90° CW and flipped horizontally
        switch (transform)
        {
        case kRotateCW:       return 2;
        case kRotateCCW:      return 4;
        case kFlipHorizontal: return 6;
        case kFlipVertical:   return 8;
        }
        break;
 
    case 6: // The image is rotated 90° CCW
        switch (transform)
        {
        case kRotateCW:       return 3;
        case kRotateCCW:      return 1;
        case kFlipHorizontal: return 5;
        case kFlipVertical:   return 7;
        }
        break;
 
    case 7: // The image is rotated 90° CW and flipped vertically
        switch (transform)
        {
        case kRotateCW:       return 4;
        case kRotateCCW:      return 2;
        case kFlipHorizontal: return 8;
        case kFlipVertical:   return 6;
        }
        break;
 
    case 8: // The image is rotated 90° CW
        switch (transform)
        {
        case kRotateCW:       return 1;
        case kRotateCCW:      return 3;
        case kFlipHorizontal: return 7;
        case kFlipVertical:   return 5;
        }
        break;
    }
    return m_current;
}
 
 
int Orientation::FromRotation(const QString &degrees)
{
    if (degrees ==   "0") return 1;
    if (degrees ==  "90") return 6;
    if (degrees == "180") return 3;
    if (degrees == "270") return 8;
    return 0;
}
 
 
QString Orientation::Description() const
{
    return (m_file == m_current)
            ? AsText(m_file)
            : tr("File: %1, Db: %2").arg(AsText(m_file),
                                         AsText(m_current));
}
 
 
QString Orientation::AsText(int orientation)
{
    switch (orientation)
    {
    case 1:  return tr("1 (Normal)");
    case 2:  return tr("2 (H Mirror)");
    case 3:  return tr("3 (Rotate 180°)");
    case 4:  return tr("4 (V Mirror)");
    case 5:  return tr("5 (H Mirror, Rot 270°)");
    case 6:  return tr("6 (Rotate 90°)");
    case 7:  return tr("7 (H Mirror, Rot 90°)");
    case 8:  return tr("8 (Rotate 270°)");
    default: return tr("%1 (Undefined)").arg(orientation);
    }
}
 
 
class PictureMetaData : public ImageMetaData
{
public:
    explicit PictureMetaData(const QString &filePath);
    ~PictureMetaData() override = default; // libexiv2 closes file, cleans up via autoptrs
 
    bool        IsValid() override // ImageMetaData
        { return m_image.get(); }
    QStringList GetAllTags() override; // ImageMetaData
    int         GetOrientation(bool *exists = nullptr) override; // ImageMetaData
    QDateTime   GetOriginalDateTime(bool *exists = nullptr) override; // ImageMetaData
    QString     GetComment(bool *exists = nullptr) override; // ImageMetaData
 
protected:
    static QString DecodeComment(std::string rawValue);
 
    std::string GetTag(const QString &key, bool *exists = nullptr);
 
    Exiv2::Image::UniquePtr m_image;
    Exiv2::ExifData       m_exifData;
};
 
 
PictureMetaData::PictureMetaData(const QString &filePath)
    : ImageMetaData(filePath), m_image(nullptr)
{
    try
    {
        m_image = Exiv2::ImageFactory::open(filePath.toStdString());
 
        if (PictureMetaData::IsValid())
        {
            m_image->readMetadata();
            m_exifData = m_image->exifData();
        }
        else
        {
            LOG(VB_GENERAL, LOG_ERR, LOC +
                QString("Exiv2 error: Could not open file %1").arg(filePath));
        }
    }
    catch (Exiv2::Error &e)
    {
        LOG(VB_GENERAL, LOG_ERR, LOC + QString("Exiv2 exception %1").arg(e.what()));
    }
}
 
 
QStringList PictureMetaData::GetAllTags()
{
    QStringList tags;
    if (!IsValid())
        return tags;
 
    LOG(VB_FILE, LOG_DEBUG, LOC + QString("Found %1 tag(s) for file %2")
        .arg(m_exifData.count()).arg(m_filePath));
 
    Exiv2::ExifData::const_iterator i;
    for (i = m_exifData.begin(); i != m_exifData.end(); ++i)
    {
        QString label = QString::fromStdString(i->tagLabel());
 
        // Ignore empty labels
        if (label.isEmpty())
            continue;
 
        QString key = QString::fromStdString(i->key());
 
        // Ignore large values (binary/private tags)
        if (i->size() >= 256)
        {
            LOG(VB_FILE, LOG_DEBUG, LOC +
                QString("Ignoring %1 (%2, %3) : Too big")
                .arg(key, i->typeName()).arg(i->size()));
        }
        // Ignore 'Print Image Matching'
        else if (i->tag() == EXIF_PRINT_IMAGE_MATCHING)
        {
            LOG(VB_FILE, LOG_DEBUG, LOC +
                QString("Ignoring %1 (%2, %3) : Undecodable")
                .arg(key, i->typeName()).arg(i->size()));
        }
        else
        {
            // Use interpreted values
            std::string val = i->print(&m_exifData);
 
            // Comment needs charset decoding
            QString value = (key == EXIF_TAG_USERCOMMENT)
                    ? DecodeComment(val) : QString::fromStdString(val);
 
            // Nulls can arise from corrupt metadata (MakerNote)
            // Remove them as they disrupt socket comms between BE & remote FE's
            if (value.contains(QChar::Null))
            {
                LOG(VB_GENERAL, LOG_NOTICE, LOC +
                    QString("Corrupted Exif detected in %1").arg(m_filePath));
                value = "????";
            }
 
            // Encode tag
            QString str = ToString(key, label, value);
            tags << str;
 
#ifdef DUMP_METADATA_TAGS
            LOG(VB_FILE, LOG_DEBUG, LOC + QString("%1 (%2, %3)")
                .arg(str, i->typeName()).arg(i->size()));
#endif
        }
    }
    return tags;
}
 
 
std::string PictureMetaData::GetTag(const QString &key, bool *exists)
{
    std::string value;
    if (exists)
        *exists = false;
 
    if (!IsValid())
        return value;
 
    Exiv2::ExifKey exifKey = Exiv2::ExifKey(key.toStdString());
    auto exifIt = m_exifData.findKey(exifKey);
 
    if (exifIt == m_exifData.end())
        return value;
 
    if (exists)
        *exists = true;
 
    // Use raw value
    return exifIt->value().toString();
}
 
 
int PictureMetaData::GetOrientation(bool *exists)
{
    std::string value = GetTag(EXIF_TAG_ORIENTATION, exists);
    return QString::fromStdString(value).toInt();
}
 
 
QDateTime PictureMetaData::GetOriginalDateTime(bool *exists)
{
    std::string value = GetTag(EXIF_TAG_DATETIME, exists);
    QString dt = QString::fromStdString(value);
 
    // Exif time has no timezone
    return QDateTime::fromString(dt, EXIF_TAG_DATE_FORMAT);
}
 
 
QString PictureMetaData::GetComment(bool *exists)
{
    // Use User Comment or else Image Description
    bool comExists = false;
    bool desExists = false;
 
    std::string comment = GetTag(EXIF_TAG_USERCOMMENT, &comExists);
 
    if (comment.empty())
        comment = GetTag(EXIF_TAG_IMAGEDESCRIPTION, &desExists);
 
    if (exists)
        *exists = comExists || desExists;
 
    return DecodeComment(comment);
}
 
 
QString PictureMetaData::DecodeComment(std::string rawValue)
{
    // Decode charset
    Exiv2::CommentValue comVal = Exiv2::CommentValue(rawValue);
    if (comVal.charsetId() != Exiv2::CommentValue::undefined)
        rawValue = comVal.comment();
    return QString::fromStdString(rawValue);
}
 
 
class VideoMetaData : public ImageMetaData
{
public:
    explicit VideoMetaData(const QString &filePath);
    ~VideoMetaData() override;
 
    bool        IsValid() override  // ImageMetaData
        { return m_dict; }
    QStringList GetAllTags() override; // ImageMetaData
    int         GetOrientation(bool *exists = nullptr) override; // ImageMetaData
    QDateTime   GetOriginalDateTime(bool *exists = nullptr) override; // ImageMetaData
    QString     GetComment(bool *exists = nullptr) override; // ImageMetaData
 
protected:
    QString GetTag(const QString &key, bool *exists = nullptr);
 
    AVFormatContext *m_context { nullptr };
    AVDictionary    *m_dict    { nullptr };
};
 
 
VideoMetaData::VideoMetaData(const QString &filePath)
    : ImageMetaData(filePath)
{
    AVInputFormat* p_inputformat = nullptr;
 
    // Open file
    if (avformat_open_input(&m_context, filePath.toLatin1().constData(),
                            p_inputformat, nullptr) < 0)
        return;
 
    // Locate video stream
    int vidStream = av_find_best_stream(m_context, AVMEDIA_TYPE_VIDEO, -1, -1, nullptr, 0);
    if (vidStream >= 0)
        m_dict  = m_context->streams[vidStream]->metadata;
 
    if (!VideoMetaData::IsValid())
        avformat_close_input(&m_context);
}
 
 
VideoMetaData::~VideoMetaData()
{
    if (VideoMetaData::IsValid())
        avformat_close_input(&m_context);
}
 
 
QStringList VideoMetaData::GetAllTags()
{
    QStringList tags;
    if (!IsValid())
        return tags;
 
    // Only extract interesting fields:
    // For list use: mythffprobe -show_format -show_streams <file>
    QString cmd = GetAppBinDir() + MYTH_APPNAME_MYTHFFPROBE;
    QStringList args;
    args << "-loglevel quiet"
         << "-print_format compact" // Returns "section|key=value|key=value..."
         << "-pretty"               // Add units etc
         << "-show_entries "
            "format=format_long_name,duration,bit_rate:format_tags:"
            "stream=codec_long_name,codec_type,width,height,pix_fmt,color_space,avg_frame_rate"
            ",codec_tag_string,sample_rate,channels,channel_layout,bit_rate:stream_tags"
         << m_filePath;
 
    MythSystemLegacy ffprobe(cmd, args, kMSRunShell | kMSStdOut);
 
    ffprobe.Run(5s);
 
    if (ffprobe.Wait() != GENERIC_EXIT_OK)
    {
        LOG(VB_GENERAL, LOG_ERR, LOC +
            QString("Timeout or Failed: %2 %3").arg(cmd, args.join(" ")));
        return tags;
    }
 
    QByteArray result = ffprobe.ReadAll();
    QTextStream ostream(result);
    int stream = 0;
    while (!ostream.atEnd())
    {
        QStringList fields = ostream.readLine().split('|');
 
        if (fields.size() <= 1)
            // Empty section
            continue;
 
        // First fields should be "format" or "stream"
        QString prefix = "";
        QString group  = fields.takeFirst();
        if (group == "stream")
        {
            // Streams use index as group
            prefix = QString::number(stream++) + ":";
            group.append(prefix);
        }
 
        for (const auto& field : std::as_const(fields))
        {
            // Expect label=value
            QStringList parts = field.split('=');
            if (parts.size() != 2)
                continue;
 
            // Remove ffprobe "tag:" prefix
            QString label = parts[0].remove("tag:");
            QString value = parts[1];
 
            // Construct a pseudo-key for FFMPEG tags
            QString key = QString("FFmpeg.%1.%2").arg(group, label);
 
            // Add stream id to labels
            QString str = ToString(key, prefix + label, value);
            tags << str;
 
#ifdef DUMP_METADATA_TAGS
            LOG(VB_FILE, LOG_DEBUG, LOC + str);
#endif
        }
    }
    return tags;
}
 
 
QString VideoMetaData::GetTag(const QString &key, bool *exists)
{
    if (m_dict)
    {
        AVDictionaryEntry *tag = nullptr;
        while ((tag = av_dict_get(m_dict, "\0", tag, AV_DICT_IGNORE_SUFFIX)))
        {
            if (QString(tag->key) == key)
            {
                if (exists)
                    *exists = true;
                return QString::fromUtf8(tag->value);
            }
        }
    }
    if (exists)
        *exists = false;
    return {};
}
 
 
int VideoMetaData::GetOrientation(bool *exists)
{
    QString angle = GetTag(FFMPEG_TAG_ORIENTATION, exists);
    return Orientation::FromRotation(angle);
}
 
 
QDateTime VideoMetaData::GetOriginalDateTime(bool *exists)
{
    QString dt = GetTag(FFMPEG_TAG_DATETIME, exists);
 
    // Video time has no timezone
    return QDateTime::fromString(dt, FFMPEG_TAG_DATE_FORMAT);
}
 
 
QString VideoMetaData::GetComment(bool *exists)
{
    if (exists)
        *exists = false;
    return {};
}
 
 
ImageMetaData* ImageMetaData::FromPicture(const QString &filePath)
{ return new PictureMetaData(filePath); }
 
 
ImageMetaData* ImageMetaData::FromVideo(const QString &filePath)
{ return new VideoMetaData(filePath); }
 
 
const QString ImageMetaData::kSeparator = "|-|";
 
 
ImageMetaData::TagMap ImageMetaData::ToMap(const QStringList &tagStrings)
{
    TagMap tags;
    for (const auto& token : std::as_const(tagStrings))
    {
        QStringList parts = FromString(token);
        // Expect Key, Label, Value.
        if (parts.size() == 3)
        {
            // Map tags by Family.Group to keep them together
            // Within each group they will preserve list ordering
            QString group = parts[0].section('.', 0, 1);
            tags.insert(group, parts);
 
#ifdef DUMP_METADATA_TAGS
            LOG(VB_FILE, LOG_DEBUG, LOC + QString("%1 = %2").arg(group, token));
#endif
        }
    }
    return tags;
}