[FFmpeg-trac] #3743(avcodec:new): 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:  new
             Priority:  normal      |                Component:  avcodec
              Version:  git-master  |               Resolution:
             Keywords:  mpeg        |               Blocked By:
             Blocking:              |  Reproduced by developer:  0
Analyzed by developer:  0           |
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Comment (by SianLiao):

 The file (too big to attach, 13 MB) is uploaded to upload.ffmpeg.org
 under filename **3743_mpeg_progressive_seq_flip.avi

 Running ffmpeg decoder will cause "1 dup!", failing to decode a frame and
 therefore the frames 19 and 20 will be identical.

 The frame otherwise is decodable, if no context reinit happens in the code
 as described above.

 {{{
 ./ffmpeg -i 3743_mpeg_progressive_seq_flip.avi -loglevel verbose -y -an -f
 image2 "imgs/img_%05d.jpg"
 ffmpeg version N-64226-g7e8fdf0 Copyright (c) 2000-2014 the FFmpeg
 developers
   built on Jun 26 2014 19:28:40 with Apple LLVM version 5.1
 (clang-503.0.40) (based on LLVM 3.4svn)
   configuration: --disable-optimizations --disable-stripping --enable-
 debug=3
   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
 Input #0, avi, from '3743_mpeg_progressive_seq_flip.avi':
   Metadata:
     encoder         : Lavf55.33.100
   Duration: 00:00:02.21, start: 0.000000, bitrate: 50237 kb/s
     Stream #0:0: Video: mpeg2video (4:2:2) (mpg2 / 0x3267706D),
 yuv422p(tv, bt709), 1920x1080 [SAR 1:1 DAR 16:9], 51233 kb/s, 50 fps, 25
 tbr, 50 tbn, 50 tbc
     Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 48000 Hz, mono, s16p,
 64 kb/s
 [graph 0 input from stream 0:0 @ 0x7fa7585003a0] w:1920 h:1080
 pixfmt:yuv422p tb:1/50 fr:25/1 sar:1/1 sws_param:flags=2
 [auto-inserted scaler 0 @ 0x7fa758500de0] w:iw h:ih flags:'0x4' interl:0
 [format @ 0x7fa758500980] auto-inserting filter 'auto-inserted scaler 0'
 between the filter 'Parsed_null_0' and the filter 'format'
 [swscaler @ 0x7fa759000600] deprecated pixel format used, make sure you
 did set range correctly
 [auto-inserted scaler 0 @ 0x7fa758500de0] w:1920 h:1080 fmt:yuv422p
 sar:1/1 -> w:1920 h:1080 fmt:yuvj422p sar:1/1 flags:0x4
 [image2 @ 0x7fa758825a00] Using AVStream.codec.time_base as a timebase
 hint to the muxer is deprecated. Set AVStream.time_base instead.
 Output #0, image2, to 'imgs/img_%05d.jpg':
   Metadata:
     encoder         : Lavf55.44.100
     Stream #0:0: Video: mjpeg, yuvj422p, 1920x1080 [SAR 1:1 DAR 16:9],
 q=2-31, 200 kb/s, 25 fps, 25 tbn, 25 tbc
     Metadata:
       encoder         : Lavc55.68.100 mjpeg
 Stream mapping:
   Stream #0:0 -> #0:0 (mpeg2video (native) -> mjpeg (native))
 Press [q] to stop, [?] for help
 *** 1 dup!
 *** 1 dup!9 fps=0.0 q=18.0 size=N/A time=00:00:00.36 bitrate=N/A dup=1
 drop=0
 No more output streams to write to, finishing.:02.16 bitrate=N/A dup=2
 drop=0
 frame=   56 fps= 20 q=24.8 Lsize=N/A time=00:00:02.24 bitrate=N/A dup=2
 drop=0
 video:4148kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB
 muxing overhead: unknown
 Input file #0 (3743_mpeg_progressive_seq_flip.avi):
   Input stream #0:0 (video): 55 packets read (13833108 bytes); 54 frames
 decoded;
   Input stream #0:1 (audio): 31 packets read (5952 bytes);
   Total: 86 packets (13839060 bytes) demuxed
 Output file #0 (imgs/img_%05d.jpg):
   Output stream #0:0 (video): 56 frames encoded; 56 packets muxed (4247491
 bytes);
   Total: 56 packets (4247491 bytes) muxed

 }}}

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Ticket URL: <https://trac.ffmpeg.org/ticket/3743#comment:2>
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