extract_metadata()

void MayaFlux::IO::SoundFileReader::extract_metadata ( const std::shared_ptr< FFmpegContext > &  ctx )

private

Extract metadata from the file.

Definition at line 345 of file SoundFileReader.cpp.

{
    if (!ctx || !ctx->is_valid()) {
        return;
    }
 
    std::lock_guard<std::mutex> meta_lock(m_metadata_mutex);
 
    FileMetadata metadata;
 
    metadata.format = ctx->format_context->iformat->name;
    metadata.mime_type = ctx->format_context->iformat->mime_type
        ? ctx->format_context->iformat->mime_type
        : "audio/" + std::string(ctx->format_context->iformat->name);
 
    metadata.file_size = std::filesystem::file_size(m_filepath);
    auto ftime = std::filesystem::last_write_time(m_filepath);
    metadata.modification_time = std::chrono::system_clock::time_point(
        std::chrono::seconds(std::chrono::duration_cast<std::chrono::seconds>(
            ftime.time_since_epoch())));
 
    metadata.attributes["codec"] = avcodec_get_name(ctx->codec_context->codec_id);
    metadata.attributes["codec_long_name"] = ctx->codec_context->codec->long_name;
    metadata.attributes["total_frames"] = ctx->total_frames;
    metadata.attributes["sample_rate"] = ctx->sample_rate;
    metadata.attributes["channels"] = ctx->channels;
 
    char layout_desc[256];
    av_channel_layout_describe(&ctx->codec_context->ch_layout, layout_desc, sizeof(layout_desc));
    metadata.attributes["channel_layout"] = std::string(layout_desc);
    metadata.attributes["bit_rate"] = ctx->codec_context->bit_rate;
 
    if (ctx->format_context->duration != AV_NOPTS_VALUE) {
        metadata.attributes["duration_seconds"] = ctx->format_context->duration / static_cast<double>(AV_TIME_BASE);
    } else if (ctx->total_frames > 0) {
        metadata.attributes["duration_seconds"] = ctx->total_frames / static_cast<double>(ctx->sample_rate);
    }
 
    AVDictionaryEntry* tag = nullptr;
    while ((tag = av_dict_get(ctx->format_context->metadata, "", tag, AV_DICT_IGNORE_SUFFIX))) {
        metadata.attributes[std::string("tag_") + tag->key] = tag->value;
    }
 
    AVStream* stream = ctx->format_context->streams[ctx->audio_stream_index];
    tag = nullptr;
    while ((tag = av_dict_get(stream->metadata, "", tag, AV_DICT_IGNORE_SUFFIX))) {
        metadata.attributes[std::string("stream_") + tag->key] = tag->value;
    }
 
    m_cached_metadata = metadata;
}

References MayaFlux::IO::FileMetadata::attributes, MayaFlux::IO::FileMetadata::file_size, MayaFlux::IO::FileMetadata::format, m_cached_metadata, m_filepath, m_metadata_mutex, MayaFlux::IO::FileMetadata::mime_type, and MayaFlux::IO::FileMetadata::modification_time.

Referenced by open().

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