[FFmpeg-trac] #3743(avcodec:open): mpeg2video decoder loses frames when progressive_sequence flag flips

[FFmpeg]

#3743: mpeg2video decoder loses frames when progressive_sequence flag flips
-------------------------------------+-------------------------------------
             Reporter:  SianLiao     |                    Owner:
                 Type:  defect       |                   Status:  open
             Priority:  important    |                Component:  avcodec
              Version:  git-master   |               Resolution:
             Keywords:  mpeg2video   |               Blocked By:
  regression                         |  Reproduced by developer:  1
             Blocking:               |
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
Changes (by cehoyos):

 * keywords:  mpeg => mpeg2video regression
 * priority:  normal => important
 * status:  new => open
 * reproduced:  0 => 1


Comment:

 Regression since 0127b861
 The attached sample outputs four frames for older FFmpeg versions, the
 third frame is missing since that change.
 {{{
 $ ffmpeg -vsync 0 -i 3743_mpeg_progressive_seq_flip.m2v -f framecrc -
 ffmpeg version N-64228-g057d270 Copyright (c) 2000-2014 the FFmpeg
 developers
   built on Jun 26 2014 20:00:52 with gcc 4.7 (SUSE Linux)
   configuration: --enable-gpl
   libavutil      52. 90.101 / 52. 90.101
   libavcodec     55. 68.100 / 55. 68.100
   libavformat    55. 44.100 / 55. 44.100
   libavdevice    55. 13.101 / 55. 13.101
   libavfilter     4.  9.100 /  4.  9.100
   libswscale      2.  6.100 /  2.  6.100
   libswresample   0. 19.100 /  0. 19.100
   libpostproc    52.  3.100 / 52.  3.100
 Input #0, mpegvideo, from '3743_mpeg_progressive_seq_flip.m2v':
   Duration: N/A, bitrate: N/A
     Stream #0:0: Video: mpeg2video (4:2:2), yuv422p(tv, bt709), 1920x1080
 [SAR 1:1 DAR 16:9], max. 50000 kb/s, 25 fps, 25 tbr, 1200k tbn, 50 tbc
 [framecrc @ 0x2430060] Using AVStream.codec.time_base as a timebase hint
 to the muxer is deprecated. Set AVStream.time_base instead.
 #software: Lavf55.44.100
 #tb 0: 1/25
 Output #0, framecrc, to 'pipe:':
   Metadata:
     encoder         : Lavf55.44.100
     Stream #0:0: Video: rawvideo (Y42B / 0x42323459), yuv422p, 1920x1080
 [SAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 25 fps, 25 tbn, 25 tbc
     Metadata:
       encoder         : Lavc55.68.100 rawvideo
 Stream mapping:
   Stream #0:0 -> #0:0 (mpeg2video (native) -> rawvideo (native))
 Press [q] to stop, [?] for help
 0,          3,          3,        1,  4147200, 0x4af40956
 0,          4,          4,        1,  4147200, 0x468d0927
 0,          6,          6,        1,  4147200, 0x32961317
 frame=    3 fps=0.0 q=0.0 Lsize=       0kB time=00:00:00.28 bitrate=
 6.0kbits/s
 video:12150kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB
 muxing overhead: unknown
 }}}

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Ticket URL: <https://trac.ffmpeg.org/ticket/3743#comment:3>
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