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.