FFMpeg Output

cjsnow@caineNET:~/Videos/Legend of Korra/Book 2/The.Legend.of.Korra.S02E03.Civil.Wars.Part.1.720p.HDTV.x264-W4F [PublicHD]$ ffmpeg -i the.legend.of.korra.s02e03.civil.wars.part.1.720p.hdtv.x264-w4f.mkv -vcodec copy -acodec copy the.legend.of.korra.s02e03.civil.wars.part.1.720p.hdtv.x264-w4f.mp4
ffmpeg version 0.8.6-4:0.8.6-0ubuntu0.12.04.1, Copyright (c) 2000-2013 the Libav developers
  built on Apr  2 2013 17:02:36 with gcc 4.6.3
*** THIS PROGRAM IS DEPRECATED ***
This program is only provided for compatibility and will be removed in a future release. Please use avconv instead.
[matroska,webm @ 0x22dd9a0] Estimating duration from bitrate, this may be inaccurate
Input #0, matroska,webm, from 'the.legend.of.korra.s02e03.civil.wars.part.1.720p.hdtv.x264-w4f.mkv':
  Duration: 00:23:03.26, start: 0.000000, bitrate: 384 kb/s
    Stream #0.0: Video: h264 (High), yuv420p, 1280x720, PAR 1:1 DAR 16:9, 23.98 fps, 23.98 tbr, 1k tbn, 47.95 tbc (default)
    Stream #0.1: Audio: ac3, 48000 Hz, 5.1, s16, 384 kb/s (default)
    Stream #0.2: Subtitle: [0][0][0][0] / 0x0000 (default)
Output #0, mp4, to 'the.legend.of.korra.s02e03.civil.wars.part.1.720p.hdtv.x264-w4f.mp4':
  Metadata:
    encoder         : Lavf53.21.1
    Stream #0.0: Video: libx264, yuv420p, 1280x720 [PAR 1:1 DAR 16:9], q=2-31, 24k tbn, 23.98 tbc (default)
    Stream #0.1: Audio: ac3, 48000 Hz, 5.1, 384 kb/s (default)
Stream mapping:
  Stream #0.0 -> #0.0
  Stream #0.1 -> #0.1
Press ctrl-c to stop encoding
[matroska,webm @ 0x22dd9a0] Read error at pos. 20978033 (0x1401971)
frame= 1177 fps=  0 q=-1.0 Lsize=   19915kB time=49.01 bitrate=3328.9kbits/s
video:17582kB audio:2302kB global headers:0kB muxing overhead 0.155305%
cjsnow@caineNET:~/Videos/Legend of Korra/Book 2/The.Legend.of.Korra.S02E03.Civil.Wars.Part.1.720p.HDTV.x264-W4F [PublicHD]$