mario@mario-pk3d:~/Vídeos/Sándalo$ avconv -i concat:sandalo_1.mod\|sandalo_2.mod -c:v libx264 -b:v 5000k -b:a 192k -s 1024x512 out.mp4
avconv version 0.8.3-4:0.8.3-0ubuntu0.12.04.1, Copyright (c) 2000-2012 the Libav developers
  built on Jun 12 2012 16:52:09 with gcc 4.6.3
Input #0, mpeg, from 'concat:sandalo_1.mod|sandalo_2.mod':
  Duration: 01:22:24.92, start: 0.513844, bitrate: 9222 kb/s
    Stream #0.0[0x1e0]: Video: mpeg2video (Main), yuv420p, 720x480 [PAR 32:27 DAR 16:9], 8900 kb/s, 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc
    Stream #0.1[0x80]: Audio: ac3, 48000 Hz, stereo, s16, 384 kb/s
Unknown encoder 'libx264'