Media Tips

This is an article about different media (and more specifically) video files can be manipulated.

This is just for historical purposes as now almost everything can be done using ffmpeg and the right options.

• libmp4v2 contains:
  • mp4art - to extract a picture (or coverart from mp4)
  • mp4info - to get meta data from mp4 streams
  • mp4tags - to set metadata and picture.
• qt-fastload to move index to the front and making mp4 streamable
• When encoding:
  • Change max GOP or IDR to around 5 seconds.
  • 2-pass avg bitrate: 800 or even 500...

Concatenating files:

ffmpeg

ffmpeg has a feature concat, like

ffmpeg -i concat:"video1.ts|video2.ts"

There is also a "concat" video filter that may be useful. See http://ffmpeg.org/trac/ffmpeg/wiki/How%20to%20concatenate%20%28join,%20merge%29%20media%20files

gpac

An alternative is gpac. One command it includes is MP4Box to concatenate MP4s

mp4box -cat sbd0.mp4 -cat sbd1.mp4 -new sbd.mp4

AviDemux

Of course the avidemux GUI can append files.

Final notes

So far I have not been able to create a reliable media concat recipe.

Media Gain

mp3gain can be used to normalize volume levels (without re-encoding). Accomplish this by using ReplayGain that needs to be supported by player. (XBMC claims to supports this).