> From: ffmpeg-devel <ffmpeg-devel-boun...@ffmpeg.org> On Behalf Of Raphaël > Zumer > Sent: 2023年7月26日 21:38 > To: ffmpeg-devel@ffmpeg.org > Subject: Re: [FFmpeg-devel] [PATCH 1/2] avformat/movenc: fix sample size > being zero in pcmC > > On 7/25/23 23:45, Zhao Zhili wrote: > > From: Zhao Zhili <zhiliz...@tencent.com> > > > > - avio_w8(pb, track->par->bits_per_raw_sample); > > + sample_size = track->par->bits_per_raw_sample; > > + if (!sample_size) > > + sample_size = av_get_exact_bits_per_sample(track->par->codec_id); > > + av_assert0(sample_size); > > + avio_w8(pb, sample_size); > > Why not just replace bits_per_raw_sample completely with > av_get_exact_bits_per_sample()? > > Are there edge cases, like incorrect codec ID, or sample sizes smaller than > specified by the codec ID (and if there is ever a mismatch, > which is expected in pcmC?) > > If not, there should be no need to prioritize bits_per_raw_sample in the > first place and add a fallback - going straight to > av_get_exact_bits_per_sample() should suffice and keep the code simpler.
Check bits_per_raw_sample first for a little bit of performance. Don't use bits_per_coded_sample because it make less sense in this case and to keep the code simpler. > > As noted in another thread, bits_per_raw_sample seems to always be 0 when > muxing PCM to MP4 with FFmpeg, whereas > bits_per_coded_sample has the correct value from the samples that I tested. That's only one usecase. bits_per_coded_sample has been set while bit_per_raw_sample wasn't only because the implementation of wav demux and there's no encoding process. (You can try -c:a pcm_s16le) There are more usecases to support, e.g., only use mp4 muxer without any demuxer or encoder. User can create and set a AVCodecParameters manually, and let bits_per_coded_sample be zero. > > Raphaël Zumer > > _______________________________________________ > 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".
