On Sat, Aug 22, 2020 at 07:27:30PM +0200, Marton Balint wrote: > > > On Sat, 22 Aug 2020, [email protected] wrote: > > > On Wed, Jul 22, 2020 at 11:27:38PM +0800, [email protected] wrote: > > > From: Limin Wang <[email protected]> > > > > > > copy the atsc ac3 audio in ts like below: > > > ./ffmpeg -i atsc_audio.ts -c:v copy -c:a copy out.ts > > > Stream #0:6[0x64](eng): Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, stereo, > > > fltp, 192 kb/s > > > > > > ./ffmpeg -i out.ts > > > Before: > > > Stream #0:1[0x101](eng): Audio: ac3 ([129][0][0][0] / 0x0081), 48000 Hz, > > > stereo, fltp, 192 kb/s > > > > > > After applied patch: > > > Stream #0:1[0x101](eng): Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, > > > stereo, fltp, 192 kb/s > > > > > > Signed-off-by: Limin Wang <[email protected]> > > > --- > > > libavformat/mpegtsenc.c | 5 +++++ > > > 1 file changed, 5 insertions(+) > > > > > > diff --git a/libavformat/mpegtsenc.c b/libavformat/mpegtsenc.c > > > index a5b45fb..f060ea6 100644 > > > --- a/libavformat/mpegtsenc.c > > > +++ b/libavformat/mpegtsenc.c > > > @@ -535,6 +535,11 @@ static int mpegts_write_pmt(AVFormatContext *s, > > > MpegTSService *service) > > > *q++=1; // 1 byte, all flags sets to 0 > > > *q++=0; // omit all fields... > > > } > > > + } else { > > > + if (codec_id == AV_CODEC_ID_AC3) > > > + put_registration_descriptor(&q, MKTAG('A', 'C', '-', > > > '3')); > > > + else if (codec_id == AV_CODEC_ID_EAC3) > > > + put_registration_descriptor(&q, MKTAG('E', 'A', 'C', > > > '3')); > > > } > > > if (codec_id == AV_CODEC_ID_S302M) > > > put_registration_descriptor(&q, MKTAG('B', 'S', 'S', > > > 'D')); > > > -- > > > 1.8.3.1 > > > > > > > ping the patch, as I'll submit patch to support atsc ac3 descriptor after > > that. > > Why is this patch needed? > > https://www.atsc.org/wp-content/uploads/2015/03/A52-2018-1.pdf > > does not seem to require the use of MPEG2 registration descriptor for ATSC. > > I am not saying this is patch is bad, but some valid reason should be found > to justify it, and the fact that AC3 fourcc is reported is irrelevant, that > is just fourcc, it can be anything.
Most of my atsc ac3 sample write the mpeg2 descriptor, so I want to keep it when copy the audio stream. By "ATSC Usage of the MPEG-2 Registration Descriptor" by astc: https://smpte-ra.org/registered-mpeg-ts-ids It provides a method to uniquely and unambiguously identify formats of private data. SMPTE is the registration authority for the 32 bit format identifier field, guaranteeing that every assigned value will be unique. https://www.atsc.org/wp-content/uploads/2015/04/t3_548r1.pdf > > Thanks, > Marton > _______________________________________________ > ffmpeg-devel mailing list > [email protected] > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > [email protected] with subject "unsubscribe". -- Thanks, Limin Wang _______________________________________________ ffmpeg-devel mailing list [email protected] https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
