Creative SB0350 Hardware Programming Guide - Page 136

Creative SB0350 Manual

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B-12 File Format Creative ADPCM Wave Type Format WAVE_FORMAT_CREATIVE_ADPCM, the name for a new .WAV format tag, 0x0200 has been registered with Microsoft. The wave format header is typedef'ed with typedef struct creative_adpcmwaveformat_tag { WAVEFORMATEX ewf; WORD wRevision; } CREATIVEADPCMWAVEFORMAT; An exploded view of the structure is laid out below: Structure Members wFormatTag nChannels nSamplesPerSec nAvgBytesPerSec nBlockAlign wBitsPerSample cbExtraSize Description WAVE_FORMAT_CREATIVE_ADPCM Number of channels. 1 for mono, 2 for stereo. Sampling frequency of the data. Should be restricted to 8000, 11025, 22050 and 44100 Hz. Average data rate. Block alignment. 1 for both mono and stereo data. Number of bits per sample. The value is 4. Number of bytes of extra information in the extended WAVE 'fmt ' header. The value is 2. Revision of algorithm. The value is zero for the current definition. wRevision This information should be in the latest release of the "Microsoft Multimedia Standards Update". Where there are differences, this document is the final arbiter.

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B-12
File Format
Creative ADPCM Wave Type Format
WAVE_FORMAT_CREATIVE_ADPCM
, the name for a new .WAV format tag,
0x0200 has been registered with Microsoft.
The wave format header is
typedef
’ed with
typedef struct creative_adpcmwaveformat_tag
{
WAVEFORMATEX
ewf;
WORD
wRevision;
} CREATIVEADPCMWAVEFORMAT;
An exploded view of the structure is laid out below:
Structure Members
Description
wFormatTag
WAVE_FORMAT_CREATIVE_ADPCM
nChannels
Number of channels.
1 for mono, 2 for stereo.
nSamplesPerSec
Sampling frequency of the data.
Should be restricted to 8000, 11025, 22050 and 44100 Hz.
nAvgBytesPerSec
Average data rate.
nBlockAlign
Block alignment.
1 for both mono and stereo data.
wBitsPerSample
Number of bits per sample.
The value is 4.
cbExtraSize
Number of bytes of extra information in the extended
WAVE ‘fmt ’ header.
The value is 2.
wRevision
Revision of algorithm.
The value is zero for the current definition.
This information should be in the latest release of the “Microsoft Multimedia Standards
Update”.
Where there are differences, this document is the final arbiter.