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.
