| Message ID | tencent_BE009D6AA67FAEAD3A3BB9C1F9B4A4692E0A@qq.com |
|---|---|
| State | Accepted |
| Commit | 0c02ad857c624d75de1c6fa85098d1752dfdb771 |
| Headers | show |
| Series | [FFmpeg-devel,1/2] avformat/movenc: fix sample size being zero in pcmC | expand |
| Context | Check | Description |
|---|---|---|
| yinshiyou/make_loongarch64 | success | Make finished |
| yinshiyou/make_fate_loongarch64 | success | Make fate finished |
| andriy/make_x86 | success | Make finished |
| andriy/make_fate_x86 | success | Make fate finished |
> From: ffmpeg-devel <ffmpeg-devel-bounces@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 <zhilizhao@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-request@ffmpeg.org with subject "unsubscribe".
diff --git a/libavformat/movenc.c b/libavformat/movenc.c index f1cc80b1b3..7ef6cef46a 100644 --- a/libavformat/movenc.c +++ b/libavformat/movenc.c @@ -1225,6 +1225,7 @@ static int mov_write_pcmc_tag(AVFormatContext *s, AVIOContext *pb, MOVTrack *tra { int64_t pos = avio_tell(pb); int format_flags; + int sample_size; avio_wb32(pb, 0); /* size */ ffio_wfourcc(pb, "pcmC"); @@ -1237,7 +1238,11 @@ static int mov_write_pcmc_tag(AVFormatContext *s, AVIOContext *pb, MOVTrack *tra track->par->codec_id == AV_CODEC_ID_PCM_S24LE || track->par->codec_id == AV_CODEC_ID_PCM_S32LE); avio_w8(pb, format_flags); - 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); return update_size(pb, pos); }
From: Zhao Zhili <zhilizhao@tencent.com> bits_per_raw_sample might not set when remux raw PCM. Fix #10433. --- libavformat/movenc.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)