XSUB encoding regression

[Carl Eugen Hoyos]

(related to issue 2424)

Encoding ​http://samples.mplayerhq.hu/MPEG-VOB/ClosedCaptions/Starship_Troopers.vob with -scodec xsub produced a file with working subtitles until r19325, current git master leads to a file that shows "coded frame too small" on decoding.

$ ffmpeg -i Starship_Troopers.vob -scodec xsub -qscale 2 -ac 2 out.avi
ffmpeg version N-40924-g349c624 Copyright (c) 2000-2012 the FFmpeg developers
  built on May 21 2012 07:59:42 with gcc 4.3.2
  configuration: --cc=/usr/local/gcc-4.3.2/bin/gcc --enable-gpl --enable-libopenjpeg --enable-libvorbis --enable-libspeex --enable-libmp3lame --enable-libtheora --extra-ldflags=-lm
  libavutil      51. 53.100 / 51. 53.100
  libavcodec     54. 21.101 / 54. 21.101
  libavformat    54.  5.101 / 54.  5.101
  libavdevice    53.  4.100 / 53.  4.100
  libavfilter     2. 75.100 /  2. 75.100
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0. 15.100 /  0. 15.100
  libpostproc    52.  0.100 / 52.  0.100
[mpeg @ 0x8f0c3c0] Adjusting PTS forward
    Last message repeated 295 times
[mpeg @ 0x8f0c3c0] max_analyze_duration 5000000 reached at 5024000
Input #0, mpeg, from 'Starship_Troopers.vob':
  Duration: 00:00:51.28, start: 1986.626100, bitrate: 4620 kb/s
    Stream #0:0[0x1e0]: Video: mpeg2video (Main), yuv420p, 720x480 [SAR 32:27 DAR 16:9], 9800 kb/s, 23.98 fps, 59.94 tbr, 90k tbn, 59.94 tbc
    Stream #0:1[0x83]: Audio: ac3, 48000 Hz, stereo, s16, 192 kb/s
    Stream #0:2[0x82]: Audio: ac3, 48000 Hz, stereo, s16, 192 kb/s
    Stream #0:3[0x80]: Audio: ac3, 48000 Hz, stereo, s16, 192 kb/s
    Stream #0:4[0x81]: Audio: ac3, 48000 Hz, 5.1(side), s16, 384 kb/s
    Stream #0:5[0x20]: Subtitle: dvd_subtitle
    Stream #0:6[0x22]: Subtitle: dvd_subtitle
Please use -q:a or -q:v, -qscale is ambiguous
[buffer @ 0x8f24180] w:720 h:480 pixfmt:yuv420p tb:1/90000 sar:32/27 sws_param:flags=2
[buffersink @ 0x8f3e580] No opaque field provided
[aformat @ 0x8f13f00] auto-inserting filter 'auto-inserted resampler 0' between the filter 'src' and the filter 'aformat'
[aresample @ 0x8f13b80] r:48000Hz -> r:48000Hz
Output #0, avi, to 'out.avi':
  Metadata:
    ISFT            : Lavf54.5.101
    Stream #0:0: Video: mpeg4 (FMP4 / 0x34504D46), yuv420p, 720x480 [SAR 32:27 DAR 16:9], q=2-31, 200 kb/s, 59.94 tbn, 59.94 tbc
    Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 48000 Hz, stereo, s16
    Stream #0:2: Subtitle: xsub (DXSB / 0x42535844)
Stream mapping:
  Stream #0:0 -> #0:0 (mpeg2video -> mpeg4)
  Stream #0:4 -> #0:1 (ac3 -> libmp3lame)
  Stream #0:5 -> #0:2 (dvdsub -> xsub)
Press [q] to stop, [?] for help
[ac3 @ 0x8f44be0] frame sync error
Error while decoding stream #0:4
[mpeg @ 0x8f0c3c0] Adjusting PTS forward
    Last message repeated 28 times
frame=   30 fps=0.0 q=2.0 size=      14kB time=00:00:00.00 bitrate=   0.0kbits/s
Adjusting PTS forward
[mpeg @ 0x8f0c3c0] Adjusting PTS forward
    Last message repeated 23 times
frame=   55 fps= 54 q=2.0 size=      14kB time=00:00:00.00 bitrate=   0.0kbits/s
Adjusting PTS forward

...

Adjusting PTS forward
[mpeg @ 0x8f0c3c0] Adjusting PTS forward
    Last message repeated 30 times
frame= 1207 fps= 56 q=2.0 size=   26344kB time=00:00:47.78 bitrate=4516.7kbits/s
Adjusting PTS forward
[mpeg @ 0x8f0c3c0] Adjusting PTS forward
    Last message repeated 17 times
[mpeg2video @ 0x8f12760] ac-tex damaged at 3 27
[mpeg2video @ 0x8f12760] Warning MVs not available
[mpeg2video @ 0x8f12760] concealing 135 DC, 135 AC, 135 MV errors
[ac3 @ 0x8f44be0] incomplete frame
frame= 1229 fps= 56 q=2.0 Lsize=   28936kB time=00:00:50.95 bitrate=4652.4kbits/s
video:26785kB audio:801kB global headers:0kB muxing overhead 4.895654%

$ ffplay out.avi
ffplay version N-40924-g349c624 Copyright (c) 2003-2012 the FFmpeg developers
  built on May 21 2012 07:59:42 with gcc 4.3.2
  configuration: --cc=/usr/local/gcc-4.3.2/bin/gcc --enable-gpl --enable-libopenjpeg --enable-libvorbis --enable-libspeex --enable-libmp3lame --enable-libtheora --extra-ldflags=-lm
  libavutil      51. 53.100 / 51. 53.100
  libavcodec     54. 21.101 / 54. 21.101
  libavformat    54.  5.101 / 54.  5.101
  libavdevice    53.  4.100 / 53.  4.100
  libavfilter     2. 75.100 /  2. 75.100
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0. 15.100 /  0. 15.100
  libpostproc    52.  0.100 / 52.  0.100
[avi @ 0x8f43fe0] non-interleaved AVI
Input #0, avi, from 'out.avi':
  Metadata:
    encoder         : Lavf54.5.101
  Duration: 00:00:51.30, start: 0.000000, bitrate: 4620 kb/s
    Stream #0:0: Video: mpeg4 (Simple Profile) (FMP4 / 0x34504D46), yuv420p, 720x480 [SAR 32:27 DAR 16:9], 59.94 fps, 59.94 tbr, 59.94 tbn, 60k tbc
    Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 48000 Hz, stereo, s16, 128 kb/s
    Stream #0:2: Subtitle: xsub (DXSB / 0x42535844)
[xsub @ 0x8f4bfe0] coded frame too small
    Last message repeated 1052 times

[Michael Niedermayer]

the "coded frame too small" is fixed, is this fixing the regression or was there more ?

[Carl Eugen Hoyos]

The subtitles are ~13 seconds late with current git head, they showed up at the right time until r19325.

[Michael Niedermayer]

So the real bug is that the subtitles are out of sync ?
and r19325 has nothing to do with it, it works fine, the next commit crashes so its not known what relation it has to this bug.
Where can I find a valid xsub avi to compare the output ?

[Carl Eugen Hoyos]

Replying to michael:

So the real bug is that the subtitles are out of sync ?

Yes

and r19325 has nothing to do with it, it works fine,

That is what I tried to say above.

the next commit crashes so its not known what relation it has to this bug.

Where can I find a valid xsub avi to compare the output ?

I would have naively suggested to use r19325 to produce one, but an alternative is to use samples/sub/small.divx

[Carl Eugen Hoyos]

Fixed by Michael.