[LAD] DAB Audio frame decoder

smprocess machel at smprocess.com
Wed Oct 29 13:51:43 UTC 2008


Fred,

It's exactly what I was thinking to do. In my case, decoding MPEG audio part 
is easy. I have just to extract and to decode PAD now.
I found a book which explains the PAD part: "Digital Audio Broadcasting: 
Principles and Applications".
Thank for your time.

Regards,

Sylvain


----- Original Message ----- 
From: "Fred Gleason" <fredg at paravelsystems.com>
To: "smprocess" <machel at smprocess.com>; 
<linux-audio-dev at lists.linuxaudio.org>
Sent: Wednesday, October 29, 2008 2:16 PM
Subject: Re: [LAD] DAB Audio frame decoder


> 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 
> |
> |                           |               Paravel Systems 
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