FFmpeg

FFmpeg is Article description::a cross platform, free, open source media encoder/decoder toolkit. It contains the programs and libraries necessary to convert audio and video into a wide range of formats. FFmpeg was written by Fabrice Bellard (creator of QEMU and the BPG image format).

USE flags
Some packages know the  USE flag for enabling ffmpeg-based audio/video codec support.

The above list is non-comprehensive. Use (part of ) to see all available flags:

Emerge
If not already pulled in as a dependency of other packages, and after setting appropriate USE flags, FFmpeg:

Media player (ffplay)
If built with the  USE flag, a command line media player called  is available.

For more information consult the following commands:

Convert audio with image to video
-r 0.1 set FPS to 0.1 for faster encoding and smaller file size, but transcoding fails on PeerTube (-r 1 works but quality of art will be poor, -r 2 is better but slower).

-acodec copy will not convert audio

External resources

 * FFmpeg Wiki
 * [HOWTO using ffplay as your default player for audio/video]