Class FrameReader

mlx/data/core/video/VideoFFMPEG.cpp:136–169

RAII container for reading a single frame and managing the state associated with that

/// RAII container for reading a single frame and managing the state associated
/// with that
class FrameReader {
 public:
  FrameReader();
  ~FrameReader();

  std::shared_ptr<Array> read_frame(
      std::string filename,
      std::shared_ptr<Array> destination,
      AVFormatContext* format_context,
      AVCodecContext* decoder_context,
      AVStream* stream);

 private:
  /// the input packet (bytes from the input file)
  AVPacket* packet_;

  /// the frame from the decoder (may be on the gpu/hw)
  AVFrame* frame_;

  /// optional, the frame in main memory
  AVFrame* cpuFrame_;

  /// context used to do format translation, e.g. YUV420 to RGB
  SwsContext* scalerContext_;

  enum State { FRAME_READER_READING, FRAME_READER_FLUSHING, FRAME_READER_EOF };

  State state_;

  std::shared_ptr<Array> decode_(
      std::string filename,
      std::shared_ptr<Array> destination,
      AVCodecContext* decoder_context);
};

VideoReaderState::VideoReaderState(const std::string& filename)
    : filename_(filename) {