Broken timestamps for msmpeg4v2 in avi

[Carl Eugen Hoyos]

A user uploaded a sample for which bad timestamps are produced since ae8168074eb1c8230d9c6482102ca08a70a9c4b0 - possibly related to ticket #4042.

$ ffmpeg -i A-223555-223610-00324.avi -qscale 2 out.avi
ffmpeg version N-72081-gec38a1b Copyright (c) 2000-2015 the FFmpeg developers
  built with gcc 4.7 (SUSE Linux)
  configuration: --enable-gpl
  libavutil      54. 23.101 / 54. 23.101
  libavcodec     56. 38.101 / 56. 38.101
  libavformat    56. 33.101 / 56. 33.101
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5. 16.101 /  5. 16.101
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  1.100 /  1.  1.100
  libpostproc    53.  3.100 / 53.  3.100
[avi @ 0x1c56320] non-interleaved AVI
Guessed Channel Layout for  Input Stream #0.1 : mono
Input #0, avi, from 'A-223555-223610-00324.avi':
  Duration: 00:00:15.04, start: 0.000000, bitrate: 837 kb/s
    Stream #0:0: Video: msmpeg4v2 (MP42 / 0x3234504D), yuv420p, 384x288, 763 kb/s, 25 fps, 25 tbr, 25 tbn, 25 tbc
    Stream #0:1: Audio: pcm_u8 ([1][0][0][0] / 0x0001), 8000 Hz, 1 channels, u8, 64 kb/s
Please use -q:a or -q:v, -qscale is ambiguous
Output #0, avi, to 'out.avi':
  Metadata:
    ISFT            : Lavf56.33.101
    Stream #0:0: Video: mpeg4 (FMP4 / 0x34504D46), yuv420p, 384x288, q=2-31, 200 kb/s, 25 fps, 25 tbn, 25 tbc
    Metadata:
      encoder         : Lavc56.38.101 mpeg4
    Stream #0:1: Audio: ac3 ([0] [0][0] / 0x2000), 8000 Hz, mono, fltp, 96 kb/s
    Metadata:
      encoder         : Lavc56.38.101 ac3
Stream mapping:
  Stream #0:0 -> #0:0 (msmpeg4v2 (native) -> mpeg4 (native))
  Stream #0:1 -> #0:1 (pcm_u8 (native) -> ac3 (native))
Press [q] to stop, [?] for help
[avi @ 0x1c692c0] Non-monotonous DTS in output stream 0:1; previous: 2, current: 0; changing to 3. This may result in incorrect timestamps in the output file.
[avi @ 0x1c692c0] Non-monotonous DTS in output stream 0:1; previous: 3, current: 0; changing to 4. This may result in incorrect timestamps in the output file.
[avi @ 0x1c692c0] Non-monotonous DTS in output stream 0:1; previous: 4, current: 0; changing to 5. This may result in incorrect timestamps in the output file.

...

[avi @ 0x1c692c0] Non-monotonous DTS in output stream 0:1; previous: 74, current: 0; changing to 75. This may result in incorrect timestamps in the output file.
[avi @ 0x1c692c0] Non-monotonous DTS in output stream 0:1; previous: 75, current: 0; changing to 76. This may result in incorrect timestamps in the output file.
[avi @ 0x1c692c0] Non-monotonous DTS in output stream 0:1; previous: 76, current: 0; changing to 77. This may result in incorrect timestamps in the output file.
frame=  324 fps=0.0 q=2.0 Lsize=    4146kB time=00:00:15.04 bitrate=2258.4kbits/s
video:3950kB audio:176kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.496279%

Playing the file with FFplay leads to heavy A/V desync.

[Michael Niedermayer]

Fixed in 488383afd1275f6da53e9c83bc209c2f70d768ef