29 Oct
2008
29 Oct
'08
10:51 a.m.
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(a)paravelsystems.com>
To: "smprocess" <machel(a)smprocess.com>om>;
<linux-audio-dev(a)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
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| | Paravel Systems
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| Fresco's Discovery:
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| If you knew what you were doing you'd probably be bored.
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