x264 .mkv Fail

ffmpeg -i "Revolution OS [2001].mkv" -c:a:1 -c:v libx2
64 -b:v 1M -threads 4 "Revolution OS.mkv"

ffmpeg version N-69672-g078be09 Copyright (c) 2000-2015 the FFmpeg developers
  built with gcc 4.9.2 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-av
isynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enab
le-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --
enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-lib
modplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrw
b --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinge
r --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --en
able-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis
 --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-
libx265 --enable-libxavs --enable-libxvid --enable-lzma --enable-decklink --enab
le-zlib
  libavutil      54. 18.100 / 54. 18.100
  libavcodec     56. 21.102 / 56. 21.102
  libavformat    56. 19.100 / 56. 19.100
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5.  9.104 /  5.  9.104
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  1.100 /  1.  1.100
  libpostproc    53.  3.100 / 53.  3.100
Input #0, matroska,webm, from 'Revolution OS [2001].mkv':
  Metadata:
    encoder         : libmakemkv v1.9.1 (1.3.0/1.4.1) win(x64-release)
    creation_time   : 2015-02-09 11:46:43
  Duration: 01:25:04.16, start: 0.000000, bitrate: 5857 kb/s
    Chapter #0:0: start 0.000000, end 111.027583
    Metadata:
      title           : Chapter 01
    Chapter #0:1: start 111.027583, end 219.552667
    Metadata:
      title           : Chapter 02
    Chapter #0:2: start 219.552667, end 395.511783
    Metadata:
      title           : Chapter 03
    Chapter #0:3: start 395.511783, end 559.425533
    Metadata:
      title           : Chapter 04
    Chapter #0:4: start 559.425533, end 737.570167
    Metadata:
      title           : Chapter 05
    Chapter #0:5: start 737.570167, end 764.880783
    Metadata:
      title           : Chapter 06
    Chapter #0:6: start 764.880783, end 906.021783
    Metadata:
      title           : Chapter 07
    Chapter #0:7: start 906.021783, end 1160.475983
    Metadata:
      title           : Chapter 08
    Chapter #0:8: start 1160.475983, end 1356.772083
    Metadata:
      title           : Chapter 09
    Chapter #0:9: start 1356.772083, end 1582.497583
    Metadata:
      title           : Chapter 10
    Chapter #0:10: start 1582.497583, end 1917.315400
    Metadata:
      title           : Chapter 11
    Chapter #0:11: start 1917.315400, end 2088.519767
    Metadata:
      title           : Chapter 12
    Chapter #0:12: start 2088.519767, end 2225.339783
    Metadata:
      title           : Chapter 13
    Chapter #0:13: start 2225.339783, end 2301.649350
    Metadata:
      title           : Chapter 14
    Chapter #0:14: start 2301.649350, end 2399.180117
    Metadata:
      title           : Chapter 15
    Chapter #0:15: start 2399.180117, end 2742.456383
    Metadata:
      title           : Chapter 16
    Chapter #0:16: start 2742.456383, end 2986.116467
    Metadata:
      title           : Chapter 17
    Chapter #0:17: start 2986.116467, end 3183.363517
    Metadata:
      title           : Chapter 18
    Chapter #0:18: start 3183.363517, end 3362.308950
    Metadata:
      title           : Chapter 19
    Chapter #0:19: start 3362.308950, end 3499.128967
    Metadata:
      title           : Chapter 20
    Chapter #0:20: start 3499.128967, end 3555.101550
    Metadata:
      title           : Chapter 21
    Chapter #0:21: start 3555.101550, end 3761.808050
    Metadata:
      title           : Chapter 22
    Chapter #0:22: start 3761.808050, end 3964.410450
    Metadata:
      title           : Chapter 23
    Chapter #0:23: start 3964.410450, end 4173.018850
    Metadata:
      title           : Chapter 24
    Chapter #0:24: start 4173.018850, end 4301.146850
    Metadata:
      title           : Chapter 25
    Chapter #0:25: start 4301.146850, end 4528.407217
    Metadata:
      title           : Chapter 26
    Chapter #0:26: start 4528.407217, end 4566.445217
    Metadata:
      title           : Chapter 27
    Chapter #0:27: start 4566.445217, end 4800.228767
    Metadata:
      title           : Chapter 28
    Chapter #0:28: start 4800.228767, end 4839.768267
    Metadata:
      title           : Chapter 29
    Chapter #0:29: start 4839.768267, end 4880.709167
    Metadata:
      title           : Chapter 30
    Chapter #0:30: start 4880.709167, end 5043.505133
    Metadata:
      title           : Chapter 31
    Chapter #0:31: start 5043.505133, end 5104.160000
    Metadata:
      title           : Chapter 32
    Stream #0:0(eng): Video: mpeg2video (Main), yuv420p(tv), 720x480 [SAR 8:9 DA
R 4:3], max. 9800 kb/s, 29.97 fps, 29.97 tbr, 1k tbn, 59.94 tbc
    Stream #0:1(eng): Audio: ac3, 48000 Hz, stereo, fltp, 192 kb/s (default)
    Metadata:
      title           : Stereo
    Stream #0:2(eng): Audio: ac3, 48000 Hz, stereo, fltp, 448 kb/s
    Metadata:
      title           : Stereo
    Stream #0:3(eng): Audio: ac3, 48000 Hz, stereo, fltp, 192 kb/s
    Metadata:
      title           : Stereo
[NULL @ 00000000054da6e0] Unable to find a suitable output format for 'libx264'
libx264: Invalid argument