OpenEuphoria

Re: 4-Bit wave files??

• Posted by Bernie Ryan <bwryan at PCOM.NET> May 30, 1999
• 477 views

The most popular sound files are recorded as 8 BIT PCM ( Pulse Code
Modulation ).
With ADPM ( Adaptive Differential Pulse Code Modulation ) once a file has
been compressed it CAN NO LONGER BE EDITED or MODIFIED.

If your talking about 4 bit compressed files.

The format of the VOC block type 9 for creative labs
is the following :

-- BYTE ------------------ Description

    0      "09"
  1-3      Block length (length of digitized data in bytes plus 12)
  4-7      Samples per second ( actual sampling frequency )
    8      Bits per sample ( bits per sample after compression, if any )
    9      Channels ( 1 mono 2 stereo
10-11      Format tag:

           #0000 -- 8 bit unsigned PCM
           #0001 -- Creative 8 bit to 4 bit ADPCM
           #0002 -- Creative 8 bit to 3 bit ADPCM
           #0003 -- Creative 8 bit to 2 bit ADPCM
           #0004 -- 16 bit signed PCM
           #0006 -- CCITT a-Law
           #0007 -- CCITT u-Law
           #0200 -- Creative 16 bit to 4 bit ADPCM

12-15      Reserved ( fill with zeros )

Maybe this will give you an idea of how to decode.

Bernie