[LAD] DAB Audio frame decoder

Fred Gleason fredg at paravelsystems.com
Wed Oct 29 13:16:51 UTC 2008


On Wednesday 29 October 2008 05:18:34 am smprocess wrote:
> The audio stream that I would like to decode is composed of MPEG frame +
> PAD (ancillary data). Of course, I could separate both parts and decode
> them in two process.
> Because I didn't find API to do this, I think that I will do it my self.

I'd start by looking in the LibMad sources.  Extracting the raw ancillary data 
from L2 frames is pretty straightforward (unlike L3, where the bitstream must 
be partially uncompressed first).  Another doc that may be of some help is:

http://www.audioscience.com/internet/download/notes/note0001_MPEG_energy.pdf

Not PAD specific, but it does illustrate one technique for accessing the 
ancillary channel.

Cheers!


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| Frederick F. Gleason, Jr. |               Chief Developer               |
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