ffmpeg

macbook:temp elad$ ffmpeg -y -i input.mp4 -vf "color=color=red@.3:size=640x360 [over]; [in][over] overlay=x='if(gte(t\,2), -w+(t\-2)*20, NAN)':y=0 [out]" output.mp4
ffmpeg version 1.2.1 Copyright (c) 2000-2013 the FFmpeg developers
  built on Jun  7 2013 09:56:00 with Apple LLVM version 4.2 (clang-425.0.24) (based on LLVM 3.2svn)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/1.2.1 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-nonfree --enable-hardcoded-tables --enable-avresample --enable-vda --cc=cc --host-cflags= --host-ldflags= --enable-libx264 --enable-libfaac --enable-libmp3lame --enable-libxvid
  libavutil      52. 18.100 / 52. 18.100
  libavcodec     54. 92.100 / 54. 92.100
  libavformat    54. 63.104 / 54. 63.104
  libavdevice    54.  3.103 / 54.  3.103
  libavfilter     3. 42.103 /  3. 42.103
  libswscale      2.  2.100 /  2.  2.100
  libswresample   0. 17.102 /  0. 17.102
  libpostproc    52.  2.100 / 52.  2.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'input.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf54.59.106
  Duration: 00:00:18.13, start: 0.000000, bitrate: 633 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360 [SAR 1:1 DAR 16:9], 631 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc
    Metadata:
      handler_name    : VideoHandler
[Parsed_overlay_1 @ 0x7fb1db40e8c0] [Eval @ 0x7fff5f2b27a0] Undefined constant or missing '(' in 't-2)*20,NAN)'
Error when evaluating the expression 'if(gte(t,2), -w+(t-2)*20, NAN)'
[Parsed_color_0 @ 0x7fb1db40cfe0] Failed to configure input pad on Parsed_overlay_1
Error opening filters!