Skip to main content

Wrapper around ffmpeg and mpv that generates and compares x264 test encodes

Project description

txs (test x264 settings) is a command line tool that can generate different combinations of x264 settings and make short test encodings with ffmpeg. It also comes with a Lua script for mpv that allows you to visually compare the test encodes and find the best one based on quality, estimated file size and estimated encoding time. It looks like this:


This is the output of txs tutorial:

This is a tutorial that should get you started. Run txs -h and txs SUBCOMMAND -h for more information.

$ txs -s source.mkv -r 25:00 10 -x crf=19:me=umh samples \
  -xs subme=9/10:deblock=-2,-1/-3,-3:no-fast-pskip

The above command creates test encodes or samples with all possible combinations of the given values for "subme", "deblock" and "no-fast-pskip" in the directory "samples.orig@25:00-1.subme:deblock:no-fast-pskip". The samples are all encoded with "crf=19:me=umh", they are all 10 seconds long and start at 25 minutes in source.mkv:


By providing multiple sets of sample settings to -xs you can limit the number of combinations:

$ txs -s source.mkv -r 25:00 10 -x crf=19:me=umh samples \
  -xs subme=10/11:no-deblock deblock=-2,-1/-3,-3

This creates the following samples:


To compare encodes, use the "compare" subcommand:

$ txs -s source.mkv compare samples.orig@25:00-1.subme:deblock:no-fast-pskip

This opens mpv in fullscreen mode with a playlist of two samples. Switch between samples with "j" and "k" or toggle the original source with "o". Pick the better sample with "b", the worse with "w" or mark them as equal with "e". New samples are loaded automatically every time you make a decision. After you've rated all samples once, any samples that were marked as equal are loaded again. This process will leave you with the best sample and its settings in the end.

You can adjust the playlist size with the -p (--playlist-size) option if you want to compare more than two samples.

"Shift+w" does the same thing as "w", but it also removes the sample and its log file from the file system.

Show and hide the playlist overlay with "`".

Some final notes you might find useful:

  • Choose your sample range carefully. It should be representative of the full video. 10 seconds or less is fine to check something quickly, but use 60 seconds or more for fine tuning.

  • Increasing gamma with "6" to around 10 to 15 makes differences more obvious. (Decrease with "5".) Don't go too high or you'll watch pixels dance that nobody else will ever see.

  • Try switching between samples while playing. txs should preserve playback time, but there is a small delay when mpv seeks.

  • You can seek forward and backward by single frames with "." and ",".


Install pipx with your distro's package manager or with pip:

$ python3 -m pip install --user pipx

Then install txs with pipx:

$ pipx install txs


$ pipx upgrade txs

Install development version over current release:

$ pipx upgrade --spec git+ txs

Install development version without an existing txs installation:

$ pipx install --spec git+ txs


$ pipx uninstall pipx

Project details

Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

txs-0.1.3.tar.gz (18.0 kB view hashes)

Uploaded source

Built Distribution

txs-0.1.3-py3-none-any.whl (18.4 kB view hashes)

Uploaded py3

Supported by

AWS AWS Cloud computing and Security Sponsor Datadog Datadog Monitoring Fastly Fastly CDN Google Google Download Analytics Microsoft Microsoft PSF Sponsor Pingdom Pingdom Monitoring Sentry Sentry Error logging StatusPage StatusPage Status page