AVBufferRef for free use by the API user. FFmpeg will never check the
contents of the buffer ref. FFmpeg calls av_buffer_unref() on it when
the frame is unreferenced. av_frame_copy_props() calls create a new
reference with av_buffer_ref() for the target frame's opaque_ref field.
This is unrelated to the opaque field, although it serves a similar
purpose.
AVBufferRef for free use by the API user. FFmpeg will never check the contents of the buffer ref. FFmpeg calls av_buffer_unref() on it when the frame is unreferenced. av_frame_copy_props() calls create a new reference with av_buffer_ref() for the target frame's opaque_ref field.
This is unrelated to the opaque field, although it serves a similar purpose.