[FFmpeg-devel] [PATCH 4/4] avformat/mpegtsenc: use the correct stream_types and write HDMV descriptors for m2ts

[Andreas Rheinhardt]

John Stebbins:
> On Fri, 2020-04-10 at 21:44 +0200, Marton Balint wrote:
>> Fixes ticket #2622.
>>
>> Signed-off-by: Marton Balint <cus at passwd.hu>
>> ---
>>  libavformat/mpegtsenc.c | 58
>> ++++++++++++++++++++++++++++++++++++++++++++++++-
>>  1 file changed, 57 insertions(+), 1 deletion(-)
>>
>> diff --git a/libavformat/mpegtsenc.c b/libavformat/mpegtsenc.c
>> index add35aca89..b154675d60 100644
>> --- a/libavformat/mpegtsenc.c
>> +++ b/libavformat/mpegtsenc.c
>> @@ -359,6 +359,54 @@ static int get_dvb_stream_type(AVFormatContext
>> *s, AVStream *st)
>>      return stream_type;
>>  }
>>  
>> +static int get_m2ts_stream_type(AVFormatContext *s, AVStream *st)
>> +{
>> +    int stream_type;
>> +
>> +    switch (st->codecpar->codec_id) {
>> +    case AV_CODEC_ID_MPEG2VIDEO:
>> +        stream_type = STREAM_TYPE_VIDEO_MPEG2;
>> +        break;
>> +    case AV_CODEC_ID_H264:
>> +        stream_type = STREAM_TYPE_VIDEO_H264;
>> +        break;
>> +    case AV_CODEC_ID_VC1:
>> +        stream_type = STREAM_TYPE_VIDEO_VC1;
>> +        break;
>> +    case AV_CODEC_ID_HEVC:
>> +        stream_type = STREAM_TYPE_VIDEO_HEVC;
>> +        break;
>> +    case AV_CODEC_ID_PCM_BLURAY:
>> +        stream_type = 0x80;
>> +        break;
>> +    case AV_CODEC_ID_AC3:
>> +        stream_type = 0x81;
>> +        break;
>> +    case AV_CODEC_ID_DTS:
>> +        stream_type = (st->codecpar->channels > 6) ? 0x85 : 0x82;
>> +        break;
>> +    case AV_CODEC_ID_TRUEHD:
>> +        stream_type = 0x83;
>> +        break;
>> +    case AV_CODEC_ID_EAC3:
>> +        stream_type = 0x84;
>> +        break;
>> +    case AV_CODEC_ID_HDMV_PGS_SUBTITLE:
>> +        stream_type = 0x90;
>> +        break;
>> +    case AV_CODEC_ID_HDMV_TEXT_SUBTITLE:
>> +        stream_type = 0x92;
>> +        break;
>> +    default:
>> +        av_log(s, AV_LOG_WARNING, "Stream %d, codec %s, is muxed as
>> a private data stream "
>> +               "and may not be recognized upon reading.\n", st-
>>> index, avcodec_get_name(st->codecpar->codec_id));
>> +        stream_type = STREAM_TYPE_PRIVATE_DATA;
>> +        break;
>> +    }
>> +
>> +    return stream_type;
>> +}
>> +
>>  static int mpegts_write_pmt(AVFormatContext *s, MpegTSService
>> *service)
>>  {
>>      MpegTSWrite *ts = s->priv_data;
>> @@ -372,6 +420,14 @@ static int mpegts_write_pmt(AVFormatContext *s,
>> MpegTSService *service)
>>      q += 2; /* patched after */
>>  
>>      /* put program info here */
>> +    if (ts->m2ts_mode) {
>> +        put_registration_descriptor(&q, MKTAG('H', 'D', 'M', 'V'));
>> +        *q++ = 0x88;        // descriptor_tag -
>> hdmv_copy_control_descriptor
>> +        *q++ = 0x04;        // descriptor_length
>> +        put16(&q, 0x0fff);  // CA_System_ID
>> +        *q++ = 0xfc;        // private_data_byte
>> +        *q++ = 0xfc;        // private_data_byte
>> +    }
>>  
>>      val = 0xf000 | (q - program_info_length_ptr - 2);
>>      program_info_length_ptr[0] = val >> 8;
>> @@ -401,7 +457,7 @@ static int mpegts_write_pmt(AVFormatContext *s,
>> MpegTSService *service)
>>              break;
>>          }
>>  
>> -        stream_type = get_dvb_stream_type(s, st);
>> +        stream_type = ts->m2ts_mode ? get_m2ts_stream_type(s, st) :
>> get_dvb_stream_type(s, st);
>>  
>>          *q++ = stream_type;
>>          put16(&q, 0xe000 | ts_st->pid);
> 
> I just wanted to comment on PGS subtitles.  PGS in Matroska have all
> segments combined in one packet.  m2ts requires each segment in it's
> own packet.  So remuxing PGS from Matroska to m2ts will not work
> correctly without the addition of a bsf to split segments.  
> 
> I just happen to be starting testing of just such a bsf (I also wrote a
> merge bsf to go the other way).  I hacked in some of you're patch to do
> a smoke test converting back and forth between m2ts and Matroska. Split
> bsf emits multiple packets for each input packet and merge consumes
> multiple packets for each input packet.  So I also had to do
> significant surgery on the auto bsf code in mux.c

Actually Marton hit the same problem with a bsf for mxfenc and so he has
already proposed a patchset [1] for this.

- Andreas

[1]: https://ffmpeg.org/pipermail/ffmpeg-devel/2020-March/259200.html