FAQ-0858 How are Audio PCM samples organized in memory within Symbian OS?


FAQ-0858 How are Audio PCM samples organized in memory within Symbian OS?

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Classification:	C++	Category:	Development
Created:	03/25/2003	Modified:	04/22/2003
Number:	FAQ-0858
Platform:	Not Applicable

Question:
Audio samples are either 8 or 16 bit, and are either Mono or Stereo.
How these samples are organized in 32 bit memory for 8 bit mono, 8 bit stereo, 16 bit mono and 16 bit stereo -> by organization, I mean interlaced or separate buffer for stereo, and byte / 16bit word order in 32bit word?

Answer:

Samples are interlaced, little endian, left channel first.

e.g.
8 bit mono:
31-24 23-16 15-8 7-0
N+3 N+2 N+1 N
(N is sample number)

8 bit stereo:
31-24 23-16 15-8 7-0
R+1 L+1 R L
(R is right channel sample number, L is left)

16 bit mono:
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Nh+1 Nl+1Nh Nl
(Nh is high byte of sample, Nl is low byte)

16 bit stereo:
31-24 23-16 15-8 7-0
Rh Rl Lh Ll
(Rh is high byte of right channel sample, etc)