openDecoder
Opens one independently driven decoder for stream.
A null decoder lets FFmpeg choose its default implementation by codec id. A non-null value selects that exact decoder name and refuses it unless it can decode this stream's codec. This is the selection seam used for FFmpeg-owned hardware decoders such as h264_mediacodec; it does not call a platform decoder API directly.
hardware requests an HWACCEL behind the chosen decoder (HardwareAccel); it is attached between context creation and open and fails typed when the running FFmpeg cannot honour it.
Opens one independently driven decoder for stream.
A null decoder lets FFmpeg choose its default implementation by codec id. A non-null value selects that exact decoder name and refuses it unless it can decode this stream's codec. This is the selection seam used for FFmpeg-owned hardware decoders such as h264_mediacodec; it does not call a platform decoder API directly.
hardware requests an HWACCEL behind the chosen decoder (HardwareAccel); it is attached between context creation and open and fails typed when the running FFmpeg cannot honour it.
Opens one decoder for one stream, for you to drive.
Independent of every other decoder and of the reader, which is the point: this is what lets a player decode audio and video at their own rates.
Parameters
0 lets libavcodec choose, which is usually the core count. Video gets frame-level threading, without which real-time 4K is not possible.
stops the decoder holding frames back for reordering. Right for audio in a player, wrong for video, where it costs decode efficiency.
Opens one independently driven decoder for stream.
A null decoder lets FFmpeg choose its default implementation by codec id. A non-null value selects that exact decoder name and refuses it unless it can decode this stream's codec. This is the selection seam used for FFmpeg-owned hardware decoders such as h264_mediacodec; it does not call a platform decoder API directly.
hardware requests an HWACCEL behind the chosen decoder (HardwareAccel); it is attached between context creation and open and fails typed when the running FFmpeg cannot honour it.
Opens one independently driven decoder for stream.
A null decoder lets FFmpeg choose its default implementation by codec id. A non-null value selects that exact decoder name and refuses it unless it can decode this stream's codec. This is the selection seam used for FFmpeg-owned hardware decoders such as h264_mediacodec; it does not call a platform decoder API directly.
hardware requests an HWACCEL behind the chosen decoder (HardwareAccel); it is attached between context creation and open and fails typed when the running FFmpeg cannot honour it.