I’m just looking at the bug https://trac.ffmpeg.org/ticket/8789 And I found that in this case, VTDecompressionSessionCreate will fail and return kVTVideoDecoderNotAvailableNowErr
While according to the document of [VTDecompressionSessionCreate], it is possible to give a null And let videotoolbox to choose a decoder. https://developer.apple.com/documentation/videotoolbox/1536134-vtdecompressionsessioncreate?language=occ So I think it is worth to have a second try(if we fail to create decode session in the first time). On Aug 1, 2020, 11:50 PM +0800, Mark Thompson <s...@jkqxz.net>, wrote: > On 01/08/2020 16:25, Wang Chuan wrote: > > If we fail to create a decoder specified by ourself, then try to > > let VideoToolbox pick a proper one for us. > > > > Signed-off-by: Wang Chuan <ouchu...@outlook.com> > > --- > > libavcodec/videotoolbox.c | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/libavcodec/videotoolbox.c b/libavcodec/videotoolbox.c > > index 8773de3393..9077647e25 100644 > > --- a/libavcodec/videotoolbox.c > > +++ b/libavcodec/videotoolbox.c > > @@ -837,6 +837,10 @@ static int videotoolbox_start(AVCodecContext *avctx) > > &decoder_cb, // outputCallback > > &videotoolbox->session); // decompressionSessionOut > > > > + // if we cannot create a decode session specified by ourself, then that > > videotoolbox pick one for us > > + if (status == kVTVideoDecoderNotAvailableNowErr) > > + status = VTDecompressionSessionCreate(NULL, videotoolbox->cm_fmt_desc, > > NULL, buf_attr, &decoder_cb, &videotoolbox->session); > > + > > if (decoder_spec) > > CFRelease(decoder_spec); > > if (buf_attr) > > > > Can you explain why? > > Looking at the code, it seems like the main consequence of this is to allow > decoders to be created which have not been given the extradata header, and > that isn't obviously a positive change. (Does > decoding a stream with a global header still work if this path is taken?) > > - Mark > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
