ffcvt – ffmpeg convert wrapper tool

ffcvt – ffmpeg convert wrapper tool

Debut blog for ffcvt, the ffmpeg wrapper to convert audio/video files.


  • The next-generation High Efficiency Video codec (HEVC), H.265 can produce videos visually comparable to libx264’s result, but in about half the file size.
  • Meanwhile the Opus audio codec is becoming the best thing ever for compressing audio — A 64K Opus audio stream is comparable to mp3 files of 128K to 256K bandwidth.
  • Such fantastic high efficiency audio/video codec/encoding capability has long been available in ffmpeg, but fewer people know it or use it, partly because the ffmpeg command line is not that simple for every one.
  • The ffcvt is designed to take the burden from normal Joe — All you need to do to encode a video is to give one parameter to ffcvt, i.e., the path and file name of the video to be encoded, and ffcvt will take care of the rest, using the recommended values for both audio/video encoding to properly encode it for you.
  • It can’t be more simpler than that. However, beneath the simple surface, ffcvt is versatile and powerful enough to allow you to touch every corner of audio/video encoding. There is a huge list of environment variables which will allow you tweak the encoding methods and parameters to exactly what you prefer instead.
  • Moreover, to encode a directory full of video files, including under its sub-directories, you need just to give ffcvt one single parameter, the directory location, and ffcvt will go ahead and encode all video files under that directory, including all its sub-directories as well.

Quick Usage

There is a quick usage help that comes with ffcvt, produced when it is invoked without any parameters.

The ffcvt -f testf.mp4 -debug 1 -force will invoke

ffmpeg -i testf.mp4 -c:a libopus -b:a 64k -c:v libx265 -x265-params crf=28 -y testf_.mkv

To use preset, do the following or set it in env var FFCVT_O

ffcvt -f testf.mp4 -debug 1 -force -suf $cm -- -preset $cm

Which will invoke

ffmpeg -i testf.mp4 -c:a libopus -b:a 64k -c:v libx265 -x265-params crf=28 -y testf_medium_.mkv -preset medium

Here are the final sizes and the conversion time (in seconds):

2916841  testf.mp4
1807513  testf_.mkv
1743701  testf_veryfast_.mkv   41
2111667  testf_faster_.mkv     44
1793216  testf_fast_.mkv       85
1807513  testf_medium_.mkv    120
1628502  testf_slow_.mkv      366
1521889  testf_slower_.mkv    964
1531154  testf_veryslow_.mkv 1413

I.e., if preset is not used, the default is medium.

Here is another set of results, sizes and the conversion time (in minutes):

171019470  testf.avi
 55114663  testf_veryfast_.mkv  39.2
 57287586  testf_faster_.mkv    51.07
 52950504  testf_fast_.mkv     147.11
 55641838  testf_medium_.mkv   174.25

Preset Method Comparison

The ffmpeg x265 preset determines how fast the encoding process will be. if you choose ultrafast, the encoding process is going to run fast, but the file size will be larger when compared to medium. The visual quality will be the same. Valid presets are ultrafast, superfast, veryfast, faster, fast, medium, slow, slower, veryslow and placebo.

Because that the visual quality are the same, so there is no need to go for the slower options, because you won’t be gaining anything but for the final file size. Therefore, check for yourself the above result file sizes and the conversion times, then pick a preset level you feel comfortable. The following present the same data in graphs. Click on them each to bring up bigger and most importantly, interactive graph.

preset small

preset large

I personally would go for veryfast because it produces the final size not much different than fast, medium, but only take less than a quarter of the time (but you may choose anything). I.e., I’ll use

export FFCVT_O="-preset veryfast"

so as to avoid specifying it each time when invoking ffcvt.

Tools Choices

As suggested before, don’t use avconv, use ffmpeg instead (the avconv fork was more for political reasons. I personally believe ffmpeg is technically superior although might not be politically).

As for video/movie play back, use mpv. It is a fork of mplayer2 and MPlayer, and is a true modern all-in-one movie player that can play ANYTHING, and one of the few movie players being actively developed all the time. Download link is in mpv.io, from which Ubuntu repo I get my Ubuntu ffmpeg package as well.

Give ffcvt a try.


2 thoughts on “ffcvt – ffmpeg convert wrapper tool

  1. How about a quick ‘this is how you compile it’ note for those of us that have never used go before? I just installed the golang metapackage on Linux, and have no idea how to use it. Most source packages tell you how to compile in the readme file. Is go breaking that tradition and expecting everyone to be born knowing how to use it?

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