This repositery contains several programs to process or generate Y4M files.

• shader-capture: capture a shader into a video
• y4m-merge: merge neighbouring frames (large speed-up)
• y4m-play: open a SDL window and plays the Y4M
• y4m2yuv: Y4M to YUV conversion

What is shader-capture?

shader-capture is a tool to turn a GLSL fragment shader into a raw video. It is designed to work out-of-the-box with shaders made with http://glslsandbox.com/ The output video is Y4M using the Rec. 709 color space with no chroma-subsampling (4:4:4).

What is y4m-merge?

y4m-merge merges adjacent frames of an input Y4M video. This is mostly useful to speed-up videos of clouds.

How to build these tools?

• git clone this repositery
• install a D compiler and DUB the D build tool.
• chdir in the choosen tool directory
• type dub to build
• for better performance, type dub -b release-nobounds instead
• shader-capture needs SDL2 binaries to run

How to use these tools?

All these tools use the standard input and output to allow piping.

$ y4m-tool -help

A Y4M can be encoded with ffmpeg with as an example the following line:

cat intput.y4m | ffmpeg -i - -vcodec libx264 -pix_fmt yuv420p -preset slow output.mp4