[FFmpeg-user] scene cut doesn't output to image?

[Roger Pack]

Hello all.

I noticed that this works:

ffmpeg -i sintel.mpg -vf select="gt(scene\,0.4)",scale=160:120,tile
-frames:v 1 preview.png

(creates a single tiled frame with the first frame of each scene).

However, a user pointed out [1] that if you try and extract
"thumbnails" one per scene, using the same filter, it seems to create
"the normal number" of image files, but each is a duplicate of the
first frame in that scene:

$ ffmpeg -i sintel.mpg -vf select="gt(scene\,0.4)" preview%04d.png

Anybody know what I'm doing wrong here?

Thanks!
-roger-

[1] http://ffmpeg.zeranoe.com/forum/viewtopic.php?f=7&t=680


command line/console's:

\ffmpeg-20120903-git-5d55830-win32-static\ffmpeg-20120903-git-5d55830-win32-static\bin\ffmpeg
-i ..\sintel.mpg -vf select="gt(scene\,0.4)",scale=160:120,tile
-frames:v 1 -t 60 preview.png
ffmpeg version N-44123-g5d55830 Copyright (c) 2000-2012 the FFmpeg developers
  built on Sep  2 2012 20:23:29 with gcc 4.7.1 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-pthreads
--enable-runtime-cpudetect --enable-avisynth --enable-bzlib
--enable-frei0r --enable-libass --enable-libcelt
--enable-libopencore-amrnb --enable-libopencore-amrwb
--enable-libfreetype --enable-libgsm --enable-libmp3lame
--enable-libnut --enable-libopenjpeg --enable-librtmp
--enable-libschroedinger --enable-libspeex --enable-libtheora
--enable-libutvideo --enable-libvo-aacenc --enable-libvo-amrwbenc
--enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs
--enable-libxvid --enable-zlib
  libavutil      51. 70.100 / 51. 70.100
  libavcodec     54. 55.100 / 54. 55.100
  libavformat    54. 25.104 / 54. 25.104
  libavdevice    54.  2.100 / 54.  2.100
  libavfilter     3. 15.102 /  3. 15.102
  libswscale      2.  1.101 /  2.  1.101
  libswresample   0. 15.100 /  0. 15.100
  libpostproc    52.  0.100 / 52.  0.100
[mpeg2video @ 01dd5ba0] ac-tex damaged at 40 7
[mpeg2video @ 01dd5ba0] Warning MVs not available
[mpeg2video @ 01dd5ba0] concealing 1035 DC, 1035 AC, 1035 MV errors in I frame
[mpeg @ 0234c6a0] max_analyze_duration 5000000 reached at 5024000
Input #0, mpeg, from '..\sintel.mpg':
  Duration: 00:14:47.58, start: 0.233367, bitrate: 4132 kb/s
    Stream #0:0[0x1e0]: Video: mpeg2video (Main), yuv420p, 720x480
[SAR 32:27 DAR 16:9], 7000 kb/s, 29.97 fps, 29.97 tbr, 90k tbn, 59.94
tbc
    Stream #0:1[0x80]: Audio: ac3, 48000 Hz, 5.1(side), s16, 448 kb/s
Output #0, image2, to 'preview.png':
  Metadata:
    encoder         : Lavf54.25.104
    Stream #0:0: Video: png, rgb24, 960x600 [SAR 4:3 DAR 32:15],
q=2-31, 200 kb/s, 90k tbn, 1 tbc
Stream mapping:
  Stream #0:0 -> #0:0 (mpeg2video -> png)
Press [q] to stop, [?] for help
[mpeg2video @ 01dd5ba0] ac-tex damaged at 40 7
[mpeg2video @ 01dd5ba0] Warning MVs not available
[mpeg2video @ 01dd5ba0] concealing 1035 DC, 1035 AC, 1035 MV errors in I frame
frame=    1 fps=0.0 q=0.0 Lsize=       0kB time=00:00:01.00 bitrate=
0.0kbits/s
video:837kB audio:0kB subtitle:0 global headers:0kB muxing overhead -100.000000%



>C:\installs\ffmpeg-20120903-git-5d55830-win32-static\ffmpeg-20120903-git-5d55830-win32-static\bin\ffmpeg -i ..\sintel.mpg -vf select="gt(scene\,0.4)" preview%04d.png
ffmpeg version N-44123-g5d55830 Copyright (c) 2000-2012 the FFmpeg developers
  built on Sep  2 2012 20:23:29 with gcc 4.7.1 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-pthreads
--enable-runtime-cpudetect --enable-avisynth --enable-bzlib
--enable-frei0r --enable-libass --enable-libcelt
--enable-libopencore-amrnb --enable-libopencore-amrwb
--enable-libfreetype --enable-libgsm --enable-libmp3lame
--enable-libnut --enable-libopenjpeg --enable-librtmp
--enable-libschroedinger --enable-libspeex --enable-libtheora
--enable-libutvideo --enable-libvo-aacenc --enable-libvo-amrwbenc
--enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs
--enable-libxvid --enable-zlib
  libavutil      51. 70.100 / 51. 70.100
  libavcodec     54. 55.100 / 54. 55.100
  libavformat    54. 25.104 / 54. 25.104
  libavdevice    54.  2.100 / 54.  2.100
  libavfilter     3. 15.102 /  3. 15.102
  libswscale      2.  1.101 /  2.  1.101
  libswresample   0. 15.100 /  0. 15.100
  libpostproc    52.  0.100 / 52.  0.100
[mpeg2video @ 01e3cf20] ac-tex damaged at 40 7
[mpeg2video @ 01e3cf20] Warning MVs not available
[mpeg2video @ 01e3cf20] concealing 1035 DC, 1035 AC, 1035 MV errors in I frame
[mpeg @ 01e3c560] max_analyze_duration 5000000 reached at 5024000
Input #0, mpeg, from '..\sintel.mpg':
  Duration: 00:14:47.58, start: 0.233367, bitrate: 4132 kb/s
    Stream #0:0[0x1e0]: Video: mpeg2video (Main), yuv420p, 720x480
[SAR 32:27 DAR 16:9], 7000 kb/s, 29.97 fps, 29.97 tbr, 90k tbn, 59.94
tbc
    Stream #0:1[0x80]: Audio: ac3, 48000 Hz, 5.1(side), s16, 448 kb/s
Output #0, image2, to 'preview%04d.png':
  Metadata:
    encoder         : Lavf54.25.104
    Stream #0:0: Video: png, rgb24, 720x480 [SAR 32:27 DAR 16:9],
q=2-31, 200 kb/s, 90k tbn, 29.97 tbc
Stream mapping:
  Stream #0:0 -> #0:0 (mpeg2video -> png)
Press [q] to stop, [?] for help
[mpeg2video @ 01e3cf20] ac-tex damaged at 40 7
[mpeg2video @ 01e3cf20] Warning MVs not available
[mpeg2video @ 01e3cf20] concealing 1035 DC, 1035 AC, 1035 MV errors in I frame
frame=10520 fps= 23 q=0.0 Lsize=       0kB time=00:05:51.01 bitrate=
0.0kbits/s dup=10492 drop=0
video:3484605kB audio:0kB subtitle:0 global headers:0kB muxing
overhead -100.000000%