[FFmpeg-trac] #6238(avformat:new): Wrong first TS segment length in HLS output

[FFmpeg]

#6238: Wrong first TS segment length in HLS output
----------------------------------+--------------------------------------
             Reporter:  pero      |                     Type:  defect
               Status:  new       |                 Priority:  normal
            Component:  avformat  |                  Version:  git-master
             Keywords:            |               Blocked By:
             Blocking:            |  Reproduced by developer:  0
Analyzed by developer:  0         |
----------------------------------+--------------------------------------
 Hi All!

 My original ffmpeg command is very complicated, so I reproduce this bug
 with a much simplier command, here it is:

 {{{
 ffmpeg -i 720.mp4 -c:a aac -ab 64k -c:v mpeg4 -b:v 1800k -r 25 -g 100 -f
 hls -hls_time 4 -hls_list_size 5400 -hls_flags
 +delete_segments+append_list+omit_endlist playlist.m3u8
 }}}

 output:

 {{{
 ffmpeg version N-83894-g4e3cc4b Copyright (c) 2000-2017 the FFmpeg
 developers
   built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.4) 20160609
   configuration: --enable-filter=drawtext --enable-nonfree --enable-
 libfreetype
   libavutil      55. 48.100 / 55. 48.100
   libavcodec     57. 83.100 / 57. 83.100
   libavformat    57. 66.104 / 57. 66.104
   libavdevice    57.  3.100 / 57.  3.100
   libavfilter     6. 76.100 /  6. 76.100
   libswscale      4.  3.101 /  4.  3.101
   libswresample   2.  4.100 /  2.  4.100
 Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '720.mp4':
   Metadata:
     major_brand     : isom
     minor_version   : 512
     compatible_brands: isomiso2avc1mp41
     encoder         : Lavf57.66.101
   Duration: 00:44:51.20, start: 0.000000, bitrate: 1858 kb/s
     Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p,
 1280x720 [SAR 1:1 DAR 16:9], 1802 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc
 (default)
     Metadata:
       handler_name    : VideoHandler
     Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 16000 Hz, mono,
 fltp, 51 kb/s (default)
     Metadata:
       handler_name    : SoundHandler
 Stream mapping:
   Stream #0:0 -> #0:0 (h264 (native) -> mpeg4 (native))
   Stream #0:1 -> #0:1 (aac (native) -> aac (native))
 Press [q] to stop, [?] for help
 Output #0, hls, to '2/playlist.m3u8':
   Metadata:
     major_brand     : isom
     minor_version   : 512
     compatible_brands: isomiso2avc1mp41
     encoder         : Lavf57.66.104
     Stream #0:0(und): Video: mpeg4, yuv420p, 1280x720 [SAR 1:1 DAR 16:9],
 q=2-31, 1800 kb/s, 25 fps, 90k tbn, 25 tbc (default)
     Metadata:
       handler_name    : VideoHandler
       encoder         : Lavc57.83.100 mpeg4
     Side data:
       cpb: bitrate max/min/avg: 0/0/1800000 buffer size: 0 vbv_delay: -1
     Stream #0:1(und): Audio: aac (LC), 16000 Hz, mono, fltp, 64 kb/s
 (default)
     Metadata:
       handler_name    : SoundHandler
       encoder         : Lavc57.83.100 aac
 }}}

 the created m3u8:

 {{{
 #EXTM3U
 #EXT-X-VERSION:3
 #EXT-X-TARGETDURATION:5
 #EXT-X-MEDIA-SEQUENCE:0
 #EXT-X-DISCONTINUITY
 #EXTINF:4.064000,
 playlist0.ts
 #EXTINF:4.000000,
 playlist1.ts
 #EXTINF:4.000000,
 playlist2.ts
 #EXTINF:4.000000,
 playlist3.ts
 #EXTINF:4.000000,
 playlist4.ts
 #EXTINF:4.000000,
 playlist5.ts
 #EXTINF:4.000000,
 playlist6.ts
 #EXTINF:4.000000,
 playlist7.ts
 #EXTINF:4.000000,
 }}}

 As you can see the first segment is 4.064 sec long, which is wrong.

 Thank you!

--
Ticket URL: <https://trac.ffmpeg.org/ticket/6238>
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