MP4 files on Slackware + role of some specific multimedia packages
 

Hi,

I'm currently pruning my multimedia packages, and I have a few questions.

1. What extra packages are needed to play MP4 files?

2. In which cases are FAAC/FAAD2 needed?

3. Same question for A52DEC and Xvidcore.

Cheers and happy new year to all the fellow Slackers,

Niki

To answer your questions:

1. I use mplayer (& essential codecs) and vlc

2, 3. Don't have them installed here. Go to the appropriate webisite or google them to find out what they do. You might have to come back to find out how well they do it.

AAC is a lossy audio format with better specs than the old MP3 and also, its playback is not encumbered by patents unlike MP3 for which you theoretially have to pay a license fee if you create a player device (hard- or software) for it. AAC is part of the MP4 specification and there are lots of MP4 files which combine H.264 video with AAC video.

The a52dec library is a decoder for AC3 (also called or Dolby Digital) It is similar to DTS, both are audio codecs that take input from digital SPDIF which transmit 5.1 or 7.1 surround sound and enable your audio player to demux the surround sound into separate audio signals for each speaker.

AC3 is part of the MP4 specification, just like AAC. Both audio streams are therefore possible in a MP4 video.

The faad2 library is used for decoding AAC streams whereas faac is an AAC encoder library.

XVid (the video format supported by xvidcore) is unrelated to the MP4 specification. Also, software like ffmpeg has its own implementation of an XVid codec and xvidcore library is no longer used there.

Summarizing: you can ditch faac and xvidcore if you want to be able to playback MP4 video streams, but you will also need the x264 video codec.

Thank you very much for that five star explanation!

It is a very pedantic nitpick but x264 is an encoder rather than a codec to enable playback, I suspect you actually meant 'but you will also need the H.264 video codec.' Libavcodec has had this covered for a while with variations on a native H.264 codec.

My apologies for being pedantic :(.