Increases the framerate of video files through motion interpolation. Basically a command-line (thus automatable!) version of this tutorial.

Uses InterFrame for motion interpolation (which itself uses the SVP libraries), running with AviSynth under Wine, and then piped to x264 and finally remuxed together (using mkvmerge) with the rest of the input file (which stays untouched).

Sample output

See the sample videos on Spirton's tutorial. This uses the same method with similar options, so the results will look pretty much like that.


$ ./makeitsmooth n1 n2 ... [-c configfile2 n3 n4 n5 ... [-c configfile3 n6 n7 ...]]
    In the above line, n1 and n2 would be processed using the default configuration file ./config,
    n3, n4 and n5 would be processed using configfile2, and n6, n7 would be processed using configfile3.
    nX can be an mkv file, or a directory which will be resursively searched for *.mkv files.

On first use, the script will grab a bunch of things to set up the Wine prefix with all the required Windows-y software. Everything will go under scratch next to the script.

Do not run multiple instances of this at the same time. You will run into trouble. Instead, queue the directories in a single execution.


$ cp config.sample config
$ $EDITOR config

Edit the variables as you see fit:

  • OUTPUT_DIR: Output directory. All output files will be placed there.
  • OUTPUT_FPS_NUMERATOR / OUTPUT_FPS_DENOMINATOR: Set the target framerate. The final framerate will be the ratio of these two numbers. For 60.0 Hz, simply use 60 and 1.
  • OUTPUT_HEIGHT: Resulting height of the video, in pixels. Default is 1080 pixels. The video width is rounded to the nearest multiple of 4.
  • CORES: Number of cores to use to process the video. Must be an even number. This is divided by 2 when passed to InterFrame and x264. This way, if you have CORES=4, then there will be 2 InterFrame threads and 2 x264 threads. This is also used for make -jX for compiling Wine. This number is then doubled (2 jobs per core).
  • INTERFRAME_PRESET: Name of the InterFrame preset. Possible values are Film, Animation (cartoons/anime), Smooth, Weak, or Placebo. Refer to [InterFrame's documentation] for info on these. Placebo doesn't use InterFrame; instead, it just uses AviSynth's ChangeFPS function, with no motion interpolation.
  • X264_PROFILE, X264_PRESET, X264_TUNE: Values for the x264 --profile, --preset, and --tune parameters.
  • X264_FLAGS: Extra flags you wish to pass to x264.


  • All your video files are in Matroska format.
  • There is exactly one video track. It's OK to have multiple non-video tracks.
  • The aforementioned single video track has constant framerate.
  • There is exactly one segment per file. This has nothing to do with multiple "chapters"; those are OK too. If you have no idea what a segment is, you'll be fine.
  • All your video files are uniquely-named (their converted versions all get shoved in the same output directory).
  • You want H.264 video output.
  • You are OK with lossily re-encoding your files. (You keep the originals though, so if you want you can just generate the high-framerate ones on-demand whenever you want to watch them, and then delete them afterwards.)


  • Supports arbitrary number of non-video streams per file.
  • Supports attachments (subtitle fonts, etc) and other metadata.
  • Segment UIDs and chapter information are copied from the original file, so segment linking will keep working. (aka: Your external OPs/EDs will still work fine.)


  • Basics: unzip, tar, 7z, wget, python
  • All of Wine's build dependencies (pacman -Qi wine / apt-get build-dep wine)
  • x264
  • mkvtoolnix suite (mkvmerge, mkvinfo)

Licensing is licensed under the WTFPL.


  • Preserve video title (mkvmerge --title).
  • Support running multiple instances at the same time.