bucking_avconv

avconv -i 1.dashVideo -i 1.dashAudio -vcodec copy -acodec copy -map 0:0 -map 1:0 video.mkv
avconv version 0.8.9-6:0.8.9-0ubuntu0.13.10.1, Copyright (c) 2000-2013 the Libav developers
  built on Nov  9 2013 19:09:46 with gcc 4.8.1
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '1.dashVideo':
  Metadata:
    major_brand     : dash
    minor_version   : 0
    compatible_brands: iso6avc1mp41
    creation_time   : 2013-12-31 14:51:51
  Duration: 00:12:11.00, start: 365.490333, bitrate: 811 kb/s
    Stream #0.0(und): Video: h264 (High), yuv420p, 1920x1080, 23.97 tbr, 90k tbn, 47.95 tbc
    Metadata:
      creation_time   : 2013-12-31 14:51:51
Input #1, mov,mp4,m4a,3gp,3g2,mj2, from '1.dashAudio':
  Metadata:
    major_brand     : dash
    minor_version   : 0
    compatible_brands: iso6mp41
    creation_time   : 2013-12-31 14:51:56
  Duration: 00:12:11.19, start: 365.598186, bitrate: 63 kb/s
    Stream #1.0(und): Audio: aac, 44100 Hz, stereo, s16
    Metadata:
      creation_time   : 2013-12-31 14:51:56
File 'video.mkv' already exists. Overwrite ? [y/N] y
Output #0, matroska, to 'video.mkv':
  Metadata:
    major_brand     : dash
    minor_version   : 0
    compatible_brands: iso6avc1mp41
    creation_time   : 2013-12-31 14:51:51
    encoder         : Lavf53.21.1
    Stream #0.0(und): Video: libx264, yuv420p, 1920x1080, q=2-31, 1k tbn, 90k tbc
    Metadata:
      creation_time   : 2013-12-31 14:51:51
    Stream #0.1(und): Audio: libvo_aacenc, 44100 Hz, stereo
    Metadata:
      creation_time   : 2013-12-31 14:51:56
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
  Stream #1:0 -> #0:1 (copy)
Press ctrl-c to stop encoding
frame=    0 fps=  0 q=-1.0 Lsize=    5715kB time=365.60 bitrate= 128.0kbits/s
video:0kB audio:5605kB global headers:0kB muxing overhead 1.958774%