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I had one hell of a time finding a clear document on how to write the header
of a basic PCM wav file. This is what i've found out mostly by reading docs
and a little by exploratory surgery. If ever you find any of this to be
incorrect, please let me know via email at tannoy@wep.net.
Basic structure of a simple PCM wav header.
struct{
char RiffTag[4]; // 'RIFF'
int32_t FileLength;
char FormatTag[8]; // 'WAVEfmt '
int32_t FormatLength; // 16
int16_t DataFormat;
int16_t NumChannels;
int32_t SampleRate;
int32_t BytesPerSecond;
int16_t BlockAlignment;
int16_t SampleDepth;
char DataTag[3]; // 'data'
int32_t DataLength;
} WavHeader;
FileLength:
The length of the rest of the file from this point; It comes out to
being DataLength(bytes) + 32(rest of header).
DataFormat:
The format of the sample data; PCM audio is registered as 1 for this
paramater. You can pretty much just take it as granted unless you
are using weirdo sampleing.
NumChannels:
1 or 2; Obviously mono or stereo. There can be more than 2
channels, but i cant see where that would be applied.
SampleRate:
Number of samples per second;
BytesPerSecond:
Number of bytes processed in one second; This is usefull for
buffersize estimation.
SampleRate * (SampleDepth / 8) * NumChannels;
BlockAlignment:
Number of bytes that must be read (or multiple of this) to correctly
write the sample data to the device.
(SampleDepth / 8) * NumChannels;
SampleDepth:
Number of bits per sample; Generally will be 8 or 16.
DataLength:
The length of the sampledata in bytes.
RecordTime(seconds) * (SampleDepth / 8) *
SampleRate * NumChannels
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