avformat/mpegtsenc: add registration descriptor for AC-3 and EAC3

Some DVB and ATSC captures are using the official MPEG2 registration
descriptor in addition to using the correct stream type and the
AC-3_audio_stream_descriptor/AC3_descriptor. So let's add it even if it is not
strictly needed for DVB/ATSC.

Reviewed-by: Marton Balint <cus@passwd.hu>
Signed-off-by: Limin Wang <lance.lmwang@gmail.com>

libavformat/mpegtsenc.c

@@ -487,6 +487,10 @@ static int mpegts_write_pmt(AVFormatContext *s, MpegTSService *service)
         /* write optional descriptors here */
         switch (st->codecpar->codec_type) {
         case AVMEDIA_TYPE_AUDIO:
+            if (codec_id == AV_CODEC_ID_AC3)
+                put_registration_descriptor(&q, MKTAG('A', 'C', '-', '3'));
+            if (codec_id == AV_CODEC_ID_EAC3)
+                put_registration_descriptor(&q, MKTAG('E', 'A', 'C', '3'));
             if (ts->flags & MPEGTS_FLAG_SYSTEM_B) {
                 if (codec_id == AV_CODEC_ID_AC3) {
                     DVBAC3Descriptor *dvb_ac3_desc = ts_st->dvb_ac3_desc;