x264_saliency_mod

A fork of x264 video encoder supporting custom saliency maps as an additional input to improve quality of salient objects.

An example (click to see the full-size images):

Ordinary x264	Saliency-aware x264

Getting started

You could download a build here. The archive contains an executable for Windows, if you are a Linux user, check example.sh scirpt in the archive to run the codec through wine.

Then you could compress videos taking into account their visual attention distribution as follows:

Windows:
x264.exe "source.avi" --output "source-saliency-aware.mkv" --bitrate 1000 --saliency "saliency.avi" --saliency-s0 "75%%" --saliency-bitrate "40%%"

Linux:
wine x264.exe "source.avi" --output "source-saliency-aware.mkv" --bitrate 1000 --saliency "saliency.avi" --saliency-s0 75% --saliency-bitrate 40%

The first three parameters are the same as in ordinary x264 encoder:

• "source.avi" is a path to source video;
• --output specifies a path to the compressed video;
• --bitrate specifies the average bitrate of the compressed video.

The following three parameters are the most interesting, they are responsible for saliency-aware compression:

• --saliency specifies a path to a video with saliency of source video, the more bright pixels the more bitrate they will get;
• --saliency-s0 and --saliency-bitrate specify how much bitrate salient areas will get, in this example 25% of the most salient pixels will get 40% of the bitrate;
• you can find more information about these parameters in x264.exe --help -> section Saliency-aware compression.

How it works

You could read explanation of the algorithm in the original article "A semiautomatic saliency model and its application to video compression". The paper is available here.

More details are available at project page.