Ffmpeg

compile
Compiling ffmpeg for Raspberry Pi 4 (script only works fine on RPIOS(gist)) https://ffmpeg.org/ffmpeg-protocols.html for ffmpeg protocols and command line options. 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. https://docs.nvidia.com/video-technologies/video-codec-sdk/ffmpeg-with-nvidia-gpu/ nvidia cuda compile

streaming
retroarch ffmpeg recording and live streaming scripts https://retroresolution.com/ Recording Live Gameplay in RetroPie’s RetroArch Emulators Natively on the Raspberry Pi with ffmpeg https://retroresolution.com/#li_stream_twitch stream to twitch

Stream UDP over ssh
Streaming a videofile via UDP over sshMesh and socat. Not a practical solution as ssh is TCP.

server: socat -d -d TCP-LISTEN:6800,fork,reuseaddr  UDP:localhost:8500 ffplay -protocol_whitelist file,rtp,udp -i config1.sdp  # only start ffplay after server streams udp file or use mplayer(better latency) mplayer sdp://config.sdp config.sdp is created by the ffmpeg command on the client side, copy this file over to the server side

client: function sshportforwardAndSocat { ssh -L 6800:localhost:6800 theroom@192.168.1.98 socat -d -d UDP-LISTEN:8500,fork,reuseaddr TCP:localhost:6800 }

function streaMmp4file { echo "https://trac.ffmpeg.org/wiki/StreamingGuide" echo "copy the config1.sdp file, generated by ffmpeg over to the client side" sleep 5 local thefile="redisdata.mp4" local videohost="127.0.0.1" local videoport="8500" local audioport="9010" ffmpeg -re -i "$thefile" -vcodec copy -an -f rtp rtp://"$videohost":"$videoport" \ -vn -sdp_file config1.sdp } sshportforwardAndSocat streaMmp4file

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.