avconv -i /tmp/input.mp4 -c:v mpeg4 -filter:v "scale=w=-1:h=480,scale=w=trunc(in_w/2)*2:h=trunc(in_h/2)*2" -c:a libmp3lame -t 4106 -ss 112 /tmp/output.avi
avconv version 0.8.9-6:0.8.9-1, Copyright (c) 2000-2013 the Libav developers
  built on Nov  3 2013 00:54:50 with gcc 4.7.2
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/tmp/input.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: isommp42
    creation_time   : 2013-06-23 17:36:13
  Duration: 00:38:43.15, start: 0.000000, bitrate: 829 kb/s
    Stream #0.0(eng): Video: h264 (Main), yuv420p, 848x480 [PAR 1:1 DAR 53:30], 698 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc
    Metadata:
      creation_time   : 2013-06-23 17:36:13
    Stream #0.1(eng): Audio: aac, 48000 Hz, stereo, s16, 128 kb/s
    Metadata:
      creation_time   : 2013-06-23 17:36:13
File '/tmp/output.avi' already exists. Overwrite ? [y/N] y
[buffer @ 0x25a2100] w:848 h:480 pixfmt:yuv420p
[scale @ 0x25aa700] [Eval @ 0x7fff5c4c1fe0] Undefined constant or missing '(' in 'w=-1'
[scale @ 0x25aa700] [Eval @ 0x7fff5c4c1fe0] Undefined constant or missing '(' in 'h=480'
Error when evaluating the expression 'h=480'
Error opening filters!