This new optional flag makes it easier to deal with mpegts
samples where the PMT is updated and elementary streams move
to different PIDs in the middle of playback.
Previously, new AVStreams were created per PID, and it was up
to the user to figure out which streams had migrated to a new PID
(by iterating over the list of AVProgram and making guesses), and
switch seamlessly to the new AVStream during playback.
Transcoding or remuxing these streams with ffmpeg on the CLI was
also quite painful, and the user would need to extract each set
of PIDs into a separate file and then stitch them back together.
With this new option, the mpegts demuxer will automatically detect
PMT changes and feed data from the new PID to the original AVStream
that was created for the orignal PID. For mpegts samples with
stream_identifier_descriptor available, the unique ID is used to
merge PIDs together. If the stream id is not available, the demuxer
attempts to map PIDs based on their position within the PMT.
With this change, I am able to playback and transcode/remux these
two samples which previously caused issues:
https://tmm1.s3.amazonaws.com/pmt-version-change.tshttps://kuroko.fushizen.eu/videos/pid_switch_sample.ts
I also have another longer sample in which the PMT changes
repeatedly and ES streams move to different pids three times
during playback:
https://tmm1.s3.amazonaws.com/multiple-pmt-change.ts
Demuxing this sample with the new option shows several new log
messages as the PMT changes are handled:
[mpegts] detected PMT change (program=1, version=3/6, pcr_pid=0xf98/0xfb7)
[mpegts] re-using existing video stream 0 (pid=0xf98) for new pid=0xfb7
[mpegts] re-using existing audio stream 1 (pid=0xf99) for new pid=0xfb8
[mpegts] re-using existing audio stream 2 (pid=0xf9a) for new pid=0xfb9
[mpegts] detected PMT change (program=1, version=6/3, pcr_pid=0xfb7/0xf98)
[mpegts] detected PMT change (program=1, version=3/4, pcr_pid=0xf98/0xf9b)
[mpegts] re-using existing video stream 0 (pid=0xf98) for new pid=0xf9b
[mpegts] re-using existing audio stream 1 (pid=0xf99) for new pid=0xf9c
[mpegts] re-using existing audio stream 2 (pid=0xf9a) for new pid=0xf9d
[mpegts] detected PMT change (program=1, version=4/5, pcr_pid=0xf9b/0xfa9)
[mpegts] re-using existing video stream 0 (pid=0xf98) for new pid=0xfa9
[mpegts] re-using existing audio stream 1 (pid=0xf99) for new pid=0xfaa
[mpegts] re-using existing audio stream 2 (pid=0xf9a) for new pid=0xfab
[mpegts] detected PMT change (program=1, version=5/6, pcr_pid=0xfa9/0xfb7)
Signed-off-by: Aman Gupta <aman@tmm1.net>
Some filtered mpegts streams may erroneously include PMTs for
programs that are not advertised in the PAT. This confuses ffmpeg
and most players because multiple audio/video streams are created
and it is unclear which ones actually contain data.
See for example https://tmm1.s3.amazonaws.com/unknown-pmts.ts
In this sample, the PAT advertises exactly one program. But the
pid it points to for the program's PMT contains PMTs for other
programs as well. This is because the broadcaster decided to
re-use the same pid for multiple program PMTs.
The hardware that filtered the original multi-program stream
into a single-program stream did so by rewriting the PAT to
contain only the program that was requested. But since it just
passed through the PMT pid referenced in the PAT, multiple PMTs
are still present for the other programs.
Before:
Input #0, mpegts, from 'unknown-pmts.ts':
Duration: 00:00:10.11, start: 80741.189700, bitrate: 9655 kb/s
Program 4
Stream #0:2[0x41]: Video: mpeg2video (Main) ([2][0][0][0] / 0x0002), yuv420p(tv, bt709, progressive), 1280x720 [SAR 1:1 DAR 16:9], Closed Captions, 11063 kb/s, 59.94 fps, 59.94 tbr, 90k tbn, 119.88 tbc
Stream #0:3[0x44](eng): Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, 5.1(side), fltp, 384 kb/s
Stream #0:4[0x45](spa): Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, stereo, fltp, 128 kb/s
No Program
Stream #0:0[0x31]: Video: mpeg2video ([2][0][0][0] / 0x0002), none(tv), 90k tbr, 90k tbn, 90k tbc
Stream #0:1[0x34](eng): Audio: ac3 (AC-3 / 0x332D4341), 0 channels, fltp
Stream #0:5[0x51]: Video: mpeg2video ([2][0][0][0] / 0x0002), none, 90k tbr, 90k tbn
Stream #0:6[0x54](eng): Audio: ac3 (AC-3 / 0x332D4341), 0 channels
With skip_unknown_pmt=1:
Input #0, mpegts, from 'unknown-pmts.ts':
Duration: 00:00:10.11, start: 80741.189700, bitrate: 9655 kb/s
Program 4
Stream #0:0[0x41]: Video: mpeg2video (Main) ([2][0][0][0] / 0x0002), yuv420p(tv, bt709, progressive), 1280x720 [SAR 1:1 DAR 16:9], Closed Captions, 11063 kb/s, 59.94 fps, 59.94 tbr, 90k tbn, 119.88 tbc
Stream #0:1[0x44](eng): Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, 5.1(side), fltp, 384 kb/s
Stream #0:2[0x45](spa): Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, stereo, fltp, 128 kb/s
Signed-off-by: Aman Gupta <aman@tmm1.net>
Some http/1.0 implementations, like python's SimpleHTTPServer, can only support one client connection at a time. Making a second request while the first is still connected leads to a deadlock.
This change enables multiple connections for http/1.1 servers only, which need to support keepalive by default and should have no problem with concurrent requests.
Signed-off-by: Aman Gupta <aman@tmm1.net>
This improves network throughput of the hls demuxer by avoiding
the latency introduced by downloading segments one at a time.
The problem is particularly noticable over high-latency network
connections: for instance, if RTT is 250ms, there will a 250ms idle
period between when one segment response is read and the next one
starts.
The obvious solution to this is to use HTTP pipelining, where a
second request can be sent (on the persistent http/1.1 connection)
before the first response is fully read. Unfortunately the way the
http protocol is implemented in avformat makes implementing pipleining
very complex.
Instead, this commit simulates pipelining using two separate persistent
http connections. This has the advantage of working independently of
the http_persistent option, and can be used with http/1.0 servers as
well. The pair of connections is swapped every time a new segment starts
downloading, and a request for the next segment is sent on the secondary
connection right away. This means the second response will be ready and
waiting by the time the current response is fully read.
Signed-off-by: Aman Gupta <aman@tmm1.net>
Signed-off-by: Anssi Hannula <anssi.hannula@iki.fi>
This teaches the HLS demuxer to use the HTTP protocols
multiple_requests=1 option, to take advantage of "Connection:
Keep-Alive" when downloading playlists and segments from the HLS server.
With the new option, you can avoid TCP connection and TLS negotiation
overhead, which is particularly beneficial when streaming via a
high-latency internet connection.
Similar to the http_persistent option recently implemented in hlsenc.c
Signed-off-by: Aman Gupta <aman@tmm1.net>
Signed-off-by: Anssi Hannula <anssi.hannula@iki.fi>
Fixes: loop.m3u
The default max iteration count of 1000 is arbitrary and ideas for a better solution are welcome
Found-by: Xiaohei and Wangchu from Alibaba Security Team
Previous version reviewed-by: Steven Liu <lingjiujianke@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This is safer, as a selected demuxer could still mean that it was auto-detected
by a user application
Reviewed-previously-by: Nicolas George <george@nsup.org>
Reviewed-previously-by: Andreas Cadhalpun <andreas.cadhalpun@googlemail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This code is disabled by default so not to regress endpoints sending invalid MIME, but can be enabled via AVOption 'strict_mime_boundary'
Signed-off-by: Alex Agranovsky <alex@sighthound.com>
The description is yet crappy, it merely copies the description of the
added and undocumented options and their value range. More descriptive
documentation is welcome.
Users have no means to find out from a failure how to make it work
or is it preferred to check and print a warning for h264 concat without auto_convert ?
Reviewed-by: Nicolas George <george@nsup.org>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
The first sentence of each of the modified man pages are worded a bit
awkwardly. These minor copy-edits should make them clearer.
Signed-off-by: Bryce Harrington <b.harrington@samsung.com>
Signed-off-by: Stefano Sabatini <stefasab@gmail.com>
Changes since v1 of the patch:
- enable option by default
- add documentation
- move up PTS override code after PES header parsing, to ensure we use the
last PCR before the first packet of the teletext PES packet.
The option overrides teletext packet PTS and DTS values with the timestamps
calculated from the PCR of the first program which the teletext stream is part
of and is not discarded.
Using the same teletext PID for multiple programs is possible, therefore we
need some kind of heuristics to know which program PCR we should synchronize
to. Using the first non-discarded PCR pid among the programs of the teletext
stream seemed like a good choice.
The patch does not do PCR interpolation to estimate the PCR of the teltetext
packet, it just uses the last PCR of the program, which may cause a slight
error (0.1 sec) in the teletext packet pts-es.
Based on a patch by Reimar Döffinger.
http://lists.ffmpeg.org/pipermail/ffmpeg-devel/2012-September/131610.html
Signed-off-by: Marton Balint <cus@passwd.hu>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
