Ffmpeg

install
sudo apt-get install yasm ladspa-sdk ladspa-foo-plugins ladspalist libass5 libass-dev libbluray-bdj libbluray-bin libbluray-dev libbluray-doc libbluray1 libmp3lame-dev \ libmp3lame-ocaml libmp3lame-ocaml-dev libmp3lame0 libsox-fmt-mp3 libopencv-* opencv-* python-cv-bridge python-image-geometry python-opencv python-opencv-apps gstreamer1.0-vaapi gstreamer1.0-vaapi-doc libopenjp2-* libopenjp2-7-dev libopenjp2-7-dbg libopenjp3d7 libopenjpeg-dev libopenjpeg-java libopenjpeg5 libopenjpeg5-dbg libopenjpip7 openjpeg-tools libopus-dbg libopus-dev libopus-doc libopus0 libtag1-dev libtag1-doc libtag1v5 libtagc0 libtagc0-dev libopus-ocaml libopus-ocaml-dev libopusfile-dev libopusfile-doc libopusfile0 libvorbis-java opus-tools opus-tools-dbg libfaac-dev libfaac0 fdkaac libfdk-aac0 libfdk-aac0-dbg libfdk-aac-dev libtheora-dbg libtheora-dev libtheora-doc libtheora0 libtheora-bin libtheora-ocaml libtheora-ocaml-dev libvpx-dev libvpx-doc libvpx3 libvpx3-dbg libwebp-dev libwebp5 libwebpdemux1 libwebpmux1 opencl-headers mesa-vdpau-drivers libvdpau-va-gl1 vdpauinfo vdpau-va-driver libvdpau-doc libvdpau-dev libvdpau1 libvdpau1-dbg libgsm-tools libgsm0710-0 libgsm0710-dev libgsm0710mux3 libgsm1 libgsm1-dbg libgsm1-dev sox libsox-dev libsox-fmt-all libsox-fmt-alsa libsox-fmt-ao libsox-fmt-base libsox-fmt-mp3 libsox-fmt-oss libsox-fmt-pulse libsox2 libsoxr-dev libsoxr-lsr0 libschroedinger-dev libschroedinger-doc libschroedinger-ocaml libschroedinger-ocaml-dev libschroedinger-1.0-0 libsmbclient libsmbclient-dev  smbclient  libspeex-dev libspeex1 libspeexdsp-dev libspeexdsp1 libspeex-ocaml libspeex-ocaml-dev libspeex-dbg libssh-4 libssh-dev libssh-dbg libssh-doc  libssh-gcrypt-4 libssh2-1 libssh2-1-dev libwavpack-dev libwavpack1 libxvidcore-dev libxvidcore4  libx265-dev libx265-79 libx265-doc libx264-148 libx264-dev libnetcdf-* netcdf-* libopenal-* openal-info  openssl
 * 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

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.