ffmpeg -i test100.mp4 -c:v prores -an test100_avconv.mov
ffmpeg version 1.1.git Copyright (c) 2000-2013 the FFmpeg developers
  built on Mar  4 2013 11:40:27 with Apple clang version 4.1 (tags/Apple/clang-421.11.66) (based on LLVM 3.1svn)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/HEAD --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-nonfree --enable-hardcoded-tables --enable-avresample --cc=cc --host-cflags= --host-ldflags= --enable-libx264 --enable-libfaac --enable-libmp3lame --enable-libxvid --enable-libfreetype --enable-ffplay
  libavutil      52. 17.103 / 52. 17.103
  libavcodec     54. 92.100 / 54. 92.100
  libavformat    54. 63.102 / 54. 63.102
  libavdevice    54.  3.103 / 54.  3.103
  libavfilter     3. 41.100 /  3. 41.100
  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 'test100.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: mp42mp41
    creation_time   : 2013-03-04 21:40:01
  Duration: 00:00:12.50, start: 0.000000, bitrate: 283 kb/s
    Stream #0:0(eng): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 85 kb/s, 24 fps, 24 tbr, 24k tbn, 48 tbc
    Metadata:
      creation_time   : 2013-03-04 21:40:01
      handler_name    : Mainconcept MP4 Video Media Handler
    Stream #0:1(eng): Audio: aac (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 189 kb/s
    Metadata:
      creation_time   : 2013-03-04 21:40:01
      handler_name    : Mainconcept MP4 Sound Media Handler
File 'test100_avconv.mov' already exists. Overwrite ? [y/N] y
encoding with ProRes standard (apcn) profile
[prores @ 0x7fdd84000000] encoding with ProRes standard (apcn) profile
[prores @ 0x7fdd84002800] encoding with ProRes standard (apcn) profile
[prores @ 0x7fdd84005000] encoding with ProRes standard (apcn) profile
[prores @ 0x7fdd8382c000] encoding with ProRes standard (apcn) profile
Output #0, mov, to 'test100_avconv.mov':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: mp42mp41
    encoder         : Lavf54.63.102
    Stream #0:0(eng): Video: prores (apcn) (apcn / 0x6E637061), yuv422p10le, 1280x720 [SAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 12288 tbn, 24 tbc
    Metadata:
      creation_time   : 2013-03-04 21:40:01
      handler_name    : Mainconcept MP4 Video Media Handler
Stream mapping:
  Stream #0:0 -> #0:0 (h264 -> prores)
Press [q] to stop, [?] for help
frame=  301 fps= 93 q=0.0 Lsize=    3801kB time=00:00:12.54 bitrate=2482.9kbits/s dup=1 drop=0
video:3799kB audio:0kB subtitle:0 global headers:0kB muxing overhead 0.050842%
ffmpeg -i test100.mp4 -c:v prores -an test100_avconv.mov  8.77s user 0.22s system 191% cpu 4.686 total