ffmpeg -t 30 -i 01-INtroduction.wmv -ac 2 -af "volume=10dB"  01-INtroduction.mkv
ffmpeg version 0.10.7-6:0.10.7-0jon1~precise Copyright (c) 2000-2013 the FFmpeg developers
  built on Jul 15 2013 21:27:54 with gcc 4.6.3
  configuration: --arch=amd64 --disable-stripping --enable-pthreads --enable-runtime-cpudetect --extra-version='6:0.10.7-0jon1~precise' --libdir=/usr/lib/x86_64-linux-gnu --prefix=/usr --enable-bzlib --enable-libdc1394 --enable-libfreetype --enable-frei0r --enable-gnutls --enable-libgsm --enable-libmp3lame --enable-librtmp --enable-libopencv --enable-libopenjpeg --enable-libpulse --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-vaapi --enable-vdpau --enable-libvorbis --enable-libvpx --enable-zlib --enable-gpl --enable-postproc --enable-libcdio --enable-x11grab --enable-libx264 --shlibdir=/usr/lib/x86_64-linux-gnu --enable-shared --disable-static
  avcodec     configuration: --arch=amd64 --disable-stripping --enable-pthreads --enable-runtime-cpudetect --extra-version='6:0.10.7-0jon1~precise' --libdir=/usr/lib/x86_64-linux-gnu --prefix=/usr --enable-bzlib --enable-libdc1394 --enable-libfreetype --enable-frei0r --enable-gnutls --enable-libgsm --enable-libmp3lame --enable-librtmp --enable-libopencv --enable-libopenjpeg --enable-libpulse --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-vaapi --enable-vdpau --enable-libvorbis --enable-libvpx --enable-zlib --enable-gpl --enable-postproc --enable-libcdio --enable-x11grab --enable-libx264 --shlibdir=/usr/lib/x86_64-linux-gnu --enable-shared --disable-static --enable-version3 --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libvo-aacenc --enable-libvo-amrwbenc
  libavutil      51. 35.100 / 51. 35.100
  libavcodec     53. 61.100 / 53. 61.100
  libavformat    53. 32.100 / 53. 32.100
  libavdevice    53.  4.100 / 53.  4.100
  libavfilter     2. 61.100 /  2. 61.100
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0.  6.100 /  0.  6.100
  libpostproc    52.  0.100 / 52.  0.100
[asf @ 0x1ca3680] max_analyze_duration 5000000 reached at 5194000
Input #0, asf, from '01-INtroduction.wmv':
  Metadata:
    WMFSDKVersion   : 12.0.7601.17514
    WMFSDKNeeded    : 0.0.0.0000
    IsVBR           : 0
  Duration: 00:11:57.76, start: 0.000000, bitrate: 79 kb/s
    Stream #0:0: Audio: wmav2 (a[1][0][0] / 0x0161), 44100 Hz, 1 channels, s16, 48 kb/s
    Stream #0:1: Video: vc1 (Advanced) (WVC1 / 0x31435657), yuv420p, 1024x768, 1200 kb/s, SAR 1:1 DAR 4:3, 15 tbr, 1k tbn, 1k tbc
Unrecognized option 'af'
Failed to set value 'volume=10dB' for option 'af'