Fixes PMT parsing in some mpegts streams which contain
multiple tables within the PMT pid. Previously, the parser
assumed only one table was present in each packet, and discarded
the rest of the section data after attempting to parse the first
table.
A similar issue was documented in the BeyondTV software[1], which
helped me diagnose the same bug in the ffmpeg mpegts demuxer. I also
tried DVBInspector, libdvbpsi's dvbinfo, and tstools' tsinfo to
help debug. The former two properly read PMTs with multiple tables,
whereas the last has the same bug as ffmpeg.
I've created a minimal sample[2] which contains the combined PMT.
Here's what ffmpeg probe shows before and after this patch:
Before:
Input #0, mpegts, from 'combined-pmt-tids.ts':
Duration: 00:00:01.08, start: 4932.966167, bitrate: 741 kb/s
Program 1
No Program
Stream #0:0[0xf9d]: Audio: ac3, 48000 Hz, mono, fltp, 96 kb/s
Stream #0:1[0xf9b]: Audio: mp3, 0 channels, fltp
Stream #0:2[0xf9c]: Unknown: none
After:
Input #0, mpegts, from 'combined-pmt-tids.ts':
Duration: 00:00:01.11, start: 4932.966167, bitrate: 718 kb/s
Program 1
Stream #0:0[0xf9b]: Video: mpeg2video ([2][0][0][0] / 0x0002), none(tv, top first), 29.97 fps, 29.97 tbr, 90k tbn, 90k tbc
Stream #0:1[0xf9c](eng): Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, 5.1(side), fltp, 384 kb/s
Stream #0:2[0xf9d](spa): Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, mono, fltp, 96 kb/s
With the patch, the PMT is parsed correctly so the streams are
created in the correct order, are associated with "Program 1",
and their codecs are set correctly.
[1] http://forums.snapstream.com/vb/showpost.php?p=343816&postcount=201
[2] https://s3.amazonaws.com/tmm1/combined-pmt-tids.ts
Signed-off-by: Aman Gupta <aman@tmm1.net>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This mimics the logic flow in all the other callbacks
(pat_cb, sdt_cb, m4sl_cb), and avoids calling skip_identical()
for non PMT_TID packets.
Since skip_identical modifies internal state like
MpegTSSectionFilter.last_ver, this change prevents unnecessary
reprocessing on some streams which contain multiple tables in
the PMT pid. This can be observed with streams from certain US
cable providers, which include both tid=0x2 and another unspecified
tid=0xc0.
Signed-off-by: Aman Gupta <aman@tmm1.net>
1. an audio component with an ISO_639_language_descriptor in the PMT with the
audio_type field set to 0x03
2. a supplementary_audio_descriptor with the editorial_classification field set
to 0x01
3. an ac-3_descriptor or an enhanced_ac-3_descriptor with a component_type field
with the service_type flags set to Visually Impaired
Tested-by: Łukasz Krzciuk <lkrzciuk@vewd.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
The supplementary audio descriptor is defined in ETSI EN 300 468 and
provides more details regarding accessibility audio tracks, especially
the normative annex J contains a detailed description of its use.
Its language code (if present) overrides the language code of an also
present ISO 639 language descriptor.
Note that this also changes the priority of multiple descriptors with
language from "the last descriptor with language within the ES loop" to
"specific descriptor over general ISO 639 descriptor".
Signed-off-by: Aman Gupta <aman@tmm1.net>
It is negative, so can't be used for left shifting.
This fixes ubsan runtime error: shift exponent -1 is negative
Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
It is supposed to be a flag. The only currently defined value is
AVIO_SEEKABLE_NORMAL, but other ones may be added in the future.
However all the current lavf code treats this field as a bool (mainly
for historical reasons).
Change all those cases to properly check for AVIO_SEEKABLE_NORMAL.
this removes the need to probe to discover aac streams
inside mpegts containers, thus speeding up initial playback.
Reviewed-by: Hendrik Leppkes <h.leppkes@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This allows to copy information related to the stream ID from the demuxer
to the muxer, thus allowing for example to retain information related to
synchronous and asynchronous KLV data packets. This information is used
in the muxer when remuxing to distinguish the two kind of packets (if the
information is lacking, data packets are considered synchronous).
The fate reference changes are due to the use of
av_packet_merge_side_data(), which increases the size of the output
packet size, since side data is merged into the packet data.
Currently, AVStream contains an embedded AVCodecContext instance, which
is used by demuxers to export stream parameters to the caller and by
muxers to receive stream parameters from the caller. It is also used
internally as the codec context that is passed to parsers.
In addition, it is also widely used by the callers as the decoding (when
demuxer) or encoding (when muxing) context, though this has been
officially discouraged since Libav 11.
There are multiple important problems with this approach:
- the fields in AVCodecContext are in general one of
* stream parameters
* codec options
* codec state
However, it's not clear which ones are which. It is consequently
unclear which fields are a demuxer allowed to set or a muxer allowed to
read. This leads to erratic behaviour depending on whether decoding or
encoding is being performed or not (and whether it uses the AVStream
embedded codec context).
- various synchronization issues arising from the fact that the same
context is used by several different APIs (muxers/demuxers,
parsers, bitstream filters and encoders/decoders) simultaneously, with
there being no clear rules for who can modify what and the different
processes being typically delayed with respect to each other.
- avformat_find_stream_info() making it necessary to support opening
and closing a single codec context multiple times, thus
complicating the semantics of freeing various allocated objects in the
codec context.
Those problems are resolved by replacing the AVStream embedded codec
context with a newly added AVCodecParameters instance, which stores only
the stream parameters exported by the demuxers or read by the muxers.
Note that this slightly changes behavior: it sets AVMEDIA_TYPE_UNKNOWN
if the codec type is unknown. This should be ok.
Signed-off-by: Anton Khirnov <anton@khirnov.net>
PES header size is 6 bytes (00 00 01 bf XX XX), not 0.
BluRay text subtitles use private stream 2.
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
Aman Gupta
Łukasz Krzciuk
Stefan Pöschel
Rodger Combs
Carl Eugen Hoyos
wm4
Carl Eugen Hoyos
Diego Biurrun
Alexandra Hájková
Andreas Cadhalpun
Carlos Fernandez
Anton Khirnov
Michael Niedermayer
Stefano Sabatini
Vittorio Giovara
Luca Barbato
Clément Bœsch
Nicolas George
Hendrik Leppkes
James Almer
Petri Hintukainen