% ffmpeg -i input.mkv -ss 00:08:54 -t 10 -vcodec copy -acodec copy -map 0.2:0.1 -scodec copy -y output.mkv
FFmpeg version SVN-r25472, Copyright (c) 2000-2010 the FFmpeg developers
  built on Oct 14 2010 19:11:31 with gcc 4.5.1
  configuration: --prefix=/usr --enable-gpl --enable-libmp3lame --enable-libvorbis --enable-libfaac --enable-libxvid --enable-libx264 --enable-libvpx --enable-libtheora --enable-postproc --enable-shared --enable-pthreads --enable-x11grab --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libschroedinger --enable-libopenjpeg --enable-version3 --enable-nonfree --enable-runtime-cpudetect --disable-debug
  libavutil     50.32. 3 / 50.32. 3
  libavcore      0. 9. 1 /  0. 9. 1
  libavcodec    52.92. 0 / 52.92. 0
  libavformat   52.82. 0 / 52.82. 0
  libavdevice   52. 2. 2 / 52. 2. 2
  libavfilter    1.51. 1 /  1.51. 1
  libswscale     0.12. 0 /  0.12. 0
  libpostproc   51. 2. 0 / 51. 2. 0
[matroska,webm @ 0x11a0470] Estimating duration from bitrate, this may be inaccurate

Seems stream 0 codec frame rate differs from container frame rate: 59.94 (60000/1001) -> 29.97 (60000/2002)
Input #0, matroska,webm, from 'input.mkv':
  Duration: 00:23:51.30, start: 0.000000, bitrate: N/A
    Stream #0.0(eng): Video: h264, yuv420p, 720x480, PAR 186:157 DAR 279:157, 29.97 fps, 29.97 tbr, 1k tbn, 59.94 tbc
    Metadata:
      title           : Episode 08
    Stream #0.1(eng): Audio: aac, 48000 Hz, 5.1, s16
    Metadata:
      title           : 6ch AAC
    Stream #0.2(jpn): Audio: aac, 48000 Hz, stereo, s16
    Metadata:
      title           : 2ch AAC
    Stream #0.3(eng): Subtitle: dvdsub
    Metadata:
      title           : Dialogue/Signs/Songs
    Stream #0.4(eng): Subtitle: dvdsub
    Metadata:
      title           : Signs/Songs
    Stream #0.5(eng): Subtitle: dvdsub
    Metadata:
      title           : Dialogue/Signs/Songs/Graffiti
    Stream #0.6(eng): Subtitle: dvdsub
    Metadata:
      title           : Signs/Songs/Graffiti
    Stream #0.7(eng): Subtitle: dvdsub
    Metadata:
      title           : VidNotes/Dialogue/Signs/Songs/Graffiti
    Stream #0.8(eng): Subtitle: dvdsub
    Metadata:
      title           : VidNotes/Signs/Songs/Graffiti
Number of stream maps must match number of output streams