[FFmpeg-trac] #5419(avformat:open): HLS EXT-X-DISCONTINUITY tag is not supported

[FFmpeg]

#5419: HLS EXT-X-DISCONTINUITY tag is not supported
------------------------------------+------------------------------------
             Reporter:  xyq204101   |                    Owner:
                 Type:  defect      |                   Status:  open
             Priority:  normal      |                Component:  avformat
              Version:  git-master  |               Resolution:
             Keywords:  hls         |               Blocked By:
             Blocking:              |  Reproduced by developer:  1
Analyzed by developer:  1           |
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Changes (by cehoyos):

 * status:  new => open


Comment:

 A real-world stream that allows to reproduce this was posted on the
 youtube-dl bug tracker.
 The following works as expected, playback continues after the
 discontinuity that can be seen in the status line after ten seconds:
 {{{
 $ ffplay -ss 120 http://ipad-
 streaming.cbsnews.com/media/mpx/2016/12/11/830443587743/60_1211_FullEpisode_1199010_5000/60_1211_FullEpisode_1199010_5000.m3u8
 }}}
 The following produces only ten seconds output, I stopped transcoding
 after no frames were written for several seconds, output continues after
 some time but shows horrible A/V desync:
 {{{
 $ ffmpeg -ss 120 -i http://ipad-
 streaming.cbsnews.com/media/mpx/2016/12/11/830443587743/60_1211_FullEpisode_1199010_5000/60_1211_FullEpisode_1199010_5000.m3u8
 -qscale 2 out.avi
 ffmpeg version N-83412-g8b80feb Copyright (c) 2000-2017 the FFmpeg
 developers
   built with gcc 4.7 (SUSE Linux)
   configuration: --enable-gpl
   libavutil      55. 46.100 / 55. 46.100
   libavcodec     57. 75.100 / 57. 75.100
   libavformat    57. 66.101 / 57. 66.101
   libavdevice    57.  2.100 / 57.  2.100
   libavfilter     6. 72.100 /  6. 72.100
   libswscale      4.  3.101 /  4.  3.101
   libswresample   2.  4.100 /  2.  4.100
   libpostproc    54.  2.100 / 54.  2.100
 Input #0, hls,applehttp, from 'http://ipad-
 streaming.cbsnews.com/media/mpx/2016/12/11/830443587743/60_1211_FullEpisode_1199010_5000/60_1211_FullEpisode_1199010_5000.m3u8':
   Duration: 00:43:55.58, start: 1.400000, bitrate: 0 kb/s
   Program 0
     Metadata:
       variant_bitrate : 0
     Stream #0:0: Video: h264 (Main) ([27][0][0][0] / 0x001B), yuv420p,
 1920x1080 [SAR 1:1 DAR 16:9], 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc
     Metadata:
       variant_bitrate : 0
     Stream #0:1: Audio: aac (LC) ([15][0][0][0] / 0x000F), 44100 Hz,
 stereo, fltp
     Metadata:
       variant_bitrate : 0
 Please use -q:a or -q:v, -qscale is ambiguous
 Output #0, avi, to 'out.avi':
   Metadata:
     ISFT            : Lavf57.66.101
     Stream #0:0: Video: mpeg4 (FMP4 / 0x34504D46), yuv420p, 1920x1080 [SAR
 1:1 DAR 16:9], q=2-31, 200 kb/s, 29.97 fps, 29.97 tbn, 29.97 tbc
     Metadata:
       variant_bitrate : 0
       encoder         : Lavc57.75.100 mpeg4
     Side data:
       cpb: bitrate max/min/avg: 0/0/200000 buffer size: 0 vbv_delay: -1
     Stream #0:1: Audio: ac3 ([0] [0][0] / 0x2000), 44100 Hz, stereo, fltp,
 192 kb/s
     Metadata:
       variant_bitrate : 0
       encoder         : Lavc57.75.100 ac3
 Stream mapping:
   Stream #0:0 -> #0:0 (h264 (native) -> mpeg4 (native))
   Stream #0:1 -> #0:1 (aac (native) -> ac3 (native))
 Press [q] to stop, [?] for help
 frame=  328 fps= 16 q=2.0 Lsize=    7911kB time=00:00:11.14
 bitrate=5815.0kbits/s speed=0.538x
 video:7629kB audio:256kB subtitle:0kB other streams:0kB global headers:0kB
 muxing overhead: 0.318705%
 }}}
 The issue also manifests itself for the following command line, that
 produces output starting 140 seconds after the discontinuity:
 {{{
 $ ffmpeg -ss 140 -i http://ipad-
 streaming.cbsnews.com/media/mpx/2016/12/11/830443587743/60_1211_FullEpisode_1199010_5000/60_1211_FullEpisode_1199010_5000.m3u8
 -qscale 2 out.avi
 }}}

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Ticket URL: <https://trac.ffmpeg.org/ticket/5419#comment:17>
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