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lavf/mpegts: add reading of ARIB data coding descriptor

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This enables us to read the data coding type utilized for
a specific private data stream, of which we currently are
interested in ARIB caption streams.

The component tag limitations are according to ARIB TR-B14,
and the component IDs are defined in ARIB STD-B10.
This commit is contained in:
Jan Ekström 2019-01-14 22:07:51 +02:00
parent 100bfac6d6
commit a03885b745
1 changed files with 44 additions and 0 deletions
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44
libavformat/mpegts.c
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@ -2058,6 +2058,50 @@ int ff_parse_mpeg2_descriptor(AVFormatContext *fc, AVStream *st, int stream_type
}
}
break;
case 0xfd: /* ARIB data coding type descriptor */
// STD-B24, fascicle 3, chapter 4 defines private_stream_1
// for captions
if (stream_type == STREAM_TYPE_PRIVATE_DATA) {
// This structure is defined in STD-B10, part 1, listing 5.4 and
// part 2, 6.2.20).
// Listing of data_component_ids is in STD-B10, part 2, Annex J.
// Component tag limits are documented in TR-B14, fascicle 2,
// Vol. 3, Section 2, 4.2.8.1
int actual_component_tag = st->stream_identifier - 1;
int picked_profile = FF_PROFILE_UNKNOWN;
int data_component_id = get16(pp, desc_end);
if (data_component_id < 0)
return AVERROR_INVALIDDATA;
switch (data_component_id) {
case 0x0008:
// [0x30..0x37] are component tags utilized for
// non-mobile captioning service ("profile A").
if (actual_component_tag >= 0x30 &&
actual_component_tag <= 0x37) {
picked_profile = FF_PROFILE_ARIB_PROFILE_A;
}
break;
case 0x0012:
// component tag 0x87 signifies a mobile/partial reception
// (1seg) captioning service ("profile C").
if (actual_component_tag == 0x87) {
picked_profile = FF_PROFILE_ARIB_PROFILE_C;
}
break;
default:
break;
}
if (picked_profile == FF_PROFILE_UNKNOWN)
break;
st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
st->codecpar->codec_id = AV_CODEC_ID_ARIB_CAPTION;
st->codecpar->profile = picked_profile;
st->request_probe = 0;
}
break;
default:
break;
}