NComputing VCast has this MOJO format that can play fast on their thin clients. As described here: https://support.ncomputing.com/portal/en/kb/articles/vcast-what-is-the-difference-between-web-media-and-mojo

When I installed it, it has this ffmpeg installer that was executed, so I assume it uses ffmpeg under the hood to convert MP4 to MOJO format.

However I have been trying to find what is this MOJO video format and how can I encoded videos without using the context menu action and instead run it from command line using ffmpeg.

Anybody knows a hint on this MOJO video format?


Here's the output for the ffprobe

ffprobe version N-82151-g1e660fe Copyright (c) 2007-2016 the FFmpeg developers
  built with gcc 5.4.0 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth --enable-bzlib --enable-libebur128 --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-decklink --enable-zlib
  libavutil      55. 35.100 / 55. 35.100
  libavcodec     57. 65.100 / 57. 65.100
  libavformat    57. 57.100 / 57. 57.100
  libavdevice    57.  2.100 / 57.  2.100
  libavfilter     6. 66.100 /  6. 66.100
  libswscale      4.  3.100 /  4.  3.100
  libswresample   2.  4.100 /  2.  4.100
  libpostproc    54.  2.100 / 54.  2.100
Input #0, avi, from '.\sample.mp4.hd.mojo':
    encoder         : Lavf57.57.100
  Duration: 00:37:28.85, start: 0.000000, bitrate: 10461 kb/s
    Stream #0:0: Video: mjpeg (MJPG / 0x47504A4D), yuvj420p(pc, bt470bg/unknown/unknown), 960x540 [SAR 1:1 DAR 16:9], 9745 kb/s, 20 fps, 20 tbr, 20 tbn, 20 tbc
    Stream #0:1: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 22050 Hz, 2 channels, s16, 705 kb/s
  • Never heard of it. No mention of "mojo" in FFmpeg source code. Got a sample file? Where is it getting ffmpeg from? Or are they distributing their own build of ffmpeg?
    – llogan
    Apr 9 at 18:40
  • Try ffprobe it?
    – Tom Yan
    Apr 9 at 18:48
  • @TomYan I updated the original post with the ffprobe output, it looks like it's motion jpeg Apr 9 at 19:38
  • You can see more detailed info with ffprobe -show_streams -show_format input.avi.
    – llogan
    Apr 9 at 22:23
  • So you say this, “…can play fast on their thin clients.” but the code shows as “mjpeg (MJPG / 0x47504A4D)” So one thing is not in conflict with another, but MJPEG is an ancient format. Good format, but not as well compressed and x264 or x265 which modern CPUs can handle. I mean, A tiny Chromecase can decode x265. So before deeply exploring this .mojo stuff think about what you want/need and how a modern codec might fulfill that need. I am all for exploring, but still… No need to reinvent the wheel. Apr 10 at 16:36

NComputing MOJO format is a variant MJPEG video format which can be generated with this script:

ffmpeg -i "input.mp4" -vcodec mjpeg -vf scale=min'(960,iw)':-1 -acodec pcm_s16le -ar 22050 -ac 2 -r 20 -q:v 8 -f avi "output.mojo"

Other configuration setting could be found at the installation dir, usually here: C:\Program Files\NComputing\vSpace Server Software\MojoStreaming

With the following settings:

  1. High quality -q:v 2
  2. Standard quality -q:v 5
  3. Low quality -q:v 8

The .mojo extension is used to be able to be played by the NComputing MOJO player.

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