[FFmpeg-trac] #9429(avformat:new): Invalid skip of segments on bad/slow network connections

[FFmpeg]

#9429: Invalid skip of segments on bad/slow network connections
-------------------------------------+-------------------------------------
             Reporter:  SuRGeoNix    |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:  avformat     |                  Version:  git-
             Keywords:  mpegts hls   |  master
  rtsp                               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 By opening a "network" url (tested with hls/rtsp urls) and applying a low
 bandwidth limit (5-10KB/s) you can reproduce this is issue that skips
 segments when it shouldn't. Tested with ffplay/mpv.

 hls output (ffplay)
 {{{
 [hls @ 0000017125c0f1c0] Opening
 'http://wowzaec2demo.streamlock.net/vod/mp4:BigBuckBunny_115k.mp4/media_w2141201946_2.ts'
 for reading
 [http @ 0000017125c3c180] Stream ends prematurely at 140844, should be
 237444
 [http @ 0000017125c47680] Opening
 'http://wowzaec2demo.streamlock.net/vod/mp4:BigBuckBunny_115k.mp4/media_w2141201946_3.ts'
 for reading
 [hls @ 0000017125c0f1c0] Opening
 'http://wowzaec2demo.streamlock.net/vod/mp4:BigBuckBunny_115k.mp4/media_w2141201946_3.ts'
 for reading
 [mpegts @ 0000017125c32e00] PES packet size mismatch=    0B f=0/0
 [mpegts @ 0000017125c32e00] Packet corrupt (stream = 1, dts = 1473750).
 [h264 @ 000001712b87ab40] Invalid NAL unit 0, skipping.  0B f=0/0
 [h264 @ 000001712b87ab40] error while decoding MB 5 6, bytestream -17
 [h264 @ 000001712b87ab40] concealing 104 DC, 104 AC, 104 MV errors in P
 frame
 }}}


 hls output (mpv)
 {{{
 mpv
 http://wowzaec2demo.streamlock.net/vod/mp4:BigBuckBunny_115k.mp4/playlist.m3u8
  (+) Video --vid=1 (h264 240x160 24.000fps) (389 kbps)
  (+) Audio --aid=1 (aac 2ch 12000Hz) (389 kbps)
 AO: [wasapi] 48000Hz stereo 2ch float
 VO: [gpu] 240x160 yuv420p
 AV: 00:00:11 / 00:09:56 (2%) A-V:  0.000 Dropped: 5 Cache: 3.4s/124KB
 [ffmpeg] http: Stream ends prematurely at 140844, should be 237444
 (Buffering) AV: 00:00:15 / 00:09:56 (3%) A-V:  0.000 Dropped: 5 Cache:
 0.0s/4KB
 [ffmpeg/demuxer] mpegts: PES packet size mismatch
 [ffmpeg/demuxer] mpegts: Packet corrupt (stream = 1, dts = 1473750).
 AV: 00:00:15 / 00:09:56 (3%) A-V:  0.066 Dropped: 5 Cache: 7.8s/52KB
 [ffmpeg/video] h264: Invalid NAL unit 0, skipping.
 AV: 00:00:15 / 00:09:56 (3%) A-V:  0.026 Dropped: 5 Cache: 7.8s/50KB
 [ffmpeg/video] h264: error while decoding MB 5 6, bytestream -17
 AV: 00:00:16 / 00:09:56 (3%) A-V:  0.000 Dropped: 6 Cache: 0.7s/27KB
 Invalid audio PTS: 16.384000 -> 23.125333
 Reset playback due to audio timestamp reset.
 (...) AV: 00:00:00 / 00:09:56 (0%) A-V:  0.000 Cache: 0.0s
 }}}


 rtsp output (mpv)
 {{{
 mpv rtsp://wowzaec2demo.streamlock.net/vod/mp4:BigBuckBunny_115k.mov
  (+) Video --vid=1 (h264 240x160 24.000fps)
  (+) Audio --aid=1 (aac 2ch 12000Hz)
 File tags:
  Title: BigBuckBunny_115k.mov
 AO: [wasapi] 48000Hz stereo 2ch float
 VO: [gpu] 240x160 yuv420p
 Invalid video timestamp: 0.208333 -> 0.000000
 AV: 00:00:25 / 00:09:56 (4%) A-V:  0.480 ct:  0.208 Dropped: 7

 Audio/Video desynchronisation detected! Possible reasons include too slow
 hardware, temporary CPU spikes, broken drivers, and broken files. Audio
 position will not match to the video (see A-V status field).

 AV: 00:00:31 / 00:09:56 (5%) A-V:  0.000 ct:  0.208 Dropped: 24
 Invalid audio PTS: 32.341333 -> 34.303667
 AV: 00:00:56 / 00:09:56 (9%) A-V:  0.000 ct:  2.171 Dropped: 47
 Invalid audio PTS: 56.490333 -> 60.501667
 AV: 00:00:56 / 00:09:56 (9%) A-V:  0.000 ct:  2.171 Dropped: 47
 }}}


 attached: HLS max offset log
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/9429>
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