Method VideoStream

src/Abyss/Streams/VideoStream.cpp:122–232

}

VideoStream::VideoStream(FileSystem::InputStream stream, std::optional<FileSystem::InputStream> separateAudio)
    : _stream(std::move(stream)), _ringBuffer(1024 * 4096), _texture(nullptr, SDL_DestroyTexture), _videoCodecContext(), _audioCodecContext(), _avFrame(),
      _avBuffer(), _swsContext(), _sourceRect(), _targetRect(), _microsPerFrame(0), _videoTimestamp(0) {
    _avBuffer = static_cast<unsigned char *>(av_malloc(DecodeBufferSize)); // AVIO is going to free this automagically... because why not?
    memset(_avBuffer, 0, DecodeBufferSize);

    _avioContext = avio_alloc_context(
        _avBuffer, DecodeBufferSize, 0, this,
        [](void *opaque, uint8_t *buffer, const int size) { return static_cast<VideoStream *>(opaque)->videoStreamRead(buffer, size); }, nullptr,
        [](void *opaque, const int64_t offset, const int whence) { return static_cast<VideoStream *>(opaque)->videoStreamSeek(offset, whence); });

    _avFormatContext = avformat_alloc_context();
    _avFormatContext->pb = _avioContext;
    _avFormatContext->flags |= AVFMT_FLAG_CUSTOM_IO;

    int avError;
    if ((avError = avformat_open_input(&_avFormatContext, "", nullptr, nullptr)) < 0)
        throw std::runtime_error(absl::StrCat("Failed to open AV format context: ", avErrorCodeToString(avError)));

    if ((avError = avformat_find_stream_info(_avFormatContext, nullptr)) < 0)
        throw std::runtime_error(absl::StrCat("Failed to find stream info: ", avErrorCodeToString(avError)));

    for (auto i = 0; i < _avFormatContext->nb_streams; i++) {
        if (_avFormatContext->streams[i]->codecpar->codec_type != AVMEDIA_TYPE_VIDEO)
            continue;

        _videoStreamIdx = i;
        break;
    }

    if (_videoStreamIdx == -1)
        throw std::runtime_error("Could not locate video stream.");

    for (auto i = 0; i < _avFormatContext->nb_streams; i++) {
        if (_avFormatContext->streams[i]->codecpar->codec_type != AVMEDIA_TYPE_AUDIO)
            continue;

        _audioStreamIdx = i;
        break;
    }

    _microsPerFrame = static_cast<uint64_t>(1000000 / static_cast<float>(_avFormatContext->streams[_videoStreamIdx]->r_frame_rate.num) /
                                            static_cast<float>(_avFormatContext->streams[_videoStreamIdx]->r_frame_rate.den));

    const auto videoCodecPar = _avFormatContext->streams[_videoStreamIdx]->codecpar;
    const auto videoDecoder = avcodec_find_decoder(videoCodecPar->codec_id);

    if (videoDecoder == nullptr)
        throw std::runtime_error("Missing video codec.");

    _videoCodecContext = avcodec_alloc_context3(videoDecoder);
    if ((avError = avcodec_parameters_to_context(_videoCodecContext, videoCodecPar)) < 0)
        throw std::runtime_error(absl::StrCat("Failed to apply parameters to video context: ", avErrorCodeToString(avError)));

    if ((avError = avcodec_open2(_videoCodecContext, videoDecoder, nullptr)) < 0)
        throw std::runtime_error(absl::StrCat("Failed to open video context: ", avErrorCodeToString(avError)));

    if (_audioStreamIdx >= 0) {