Ffmpeg

install
https://gist.github.com/Brainiarc7/95c9338a737aa36d9bb2931bed379219 This gist contains instructions on setting up FFmpeg and Libav to use VAAPI-based hardware accelerated encoding (on supported platforms) for H.264 (and H.265 on supported hardware) video formats.

tech
http://www.tecmint.com/ffmpeg-commands-for-video-audio-and-image-conversion-in-linux/

https://trac.ffmpeg.org/wiki/CompilationGuide/Ubuntu

https://stackoverflow.com/questions/40088222/ffmpeg-convert-video-to-images

http://www.bugcodemaster.com/article/extract-images-frame-frame-video-file-using-ffmpeg

mp3
https://superuser.com/questions/704493/ffmpeg-convert-m4a-files-to-mp3-without-significant-loss-of-information-quali

https://trac.ffmpeg.org/wiki/Encode/MP3

https://coderwall.com/p/zbevoq/convert-m4a-to-mp3-with-ffmpeg

https://rg3.github.io/youtube-dl/download.html

See Tahoe for stripping metadata.

links

 * Gist code
 * http://libav.org/ ffmpeg fork http://blog.pkh.me/p/13-the-ffmpeg-libav-situation.html
 * Gprs_and_wifi_streaming and Cctv_cameras modding, rooting webcams.