Creative SB0350 Hardware Programming Guide - Page 133

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File Format B-9 Block Type 8 This is a special block that carries only the digitized sound attributes. It MUST precede Block Type 1. Usually, this block precedes the stereo or high speed digitized sound data. The Block Header is organized as follows: BYTE BYTE WORD BYTE BYTE bBlockID; nBlockLen[3]; wTimeConstant; bPackMethod; bVoiceMode 8 3-byte block length 2-byte Time Constant Packing Method mono or stereo The header is followed immediately by Block Type 1. Here is a discussion of various fields: bBlockID The Block Type identifier is 8. nBlockLen Length of the block (in bytes), excluding the bBlockID and nBlockLen fields. The value is 4. wTimeConstant This is a 2-byte field which indicates the Time Constant of the digitized sound data in the Block Type 1. The calculation of the Time Constant is the same as described on Block Type 1, but the whole word of the result is stored here. For a 44 100Hz sampling rate mono digitized sound, the Time Constant is calculated as follows: Time Constant = 65536 - (256 000 000 / 44 100) = 59732 (0E95H)

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File Format
B-9
Block Type 8
This is a special block that carries only the digitized sound attributes.
It MUST precede
Block Type 1.
Usually, this block precedes the stereo or high speed digitized sound
data.
The Block Header is organized as follows:
BYTE
bBlockID;
// == 8
BYTE
nBlockLen[3];
// 3-byte block length
WORD
wTimeConstant;
// 2-byte Time Constant
BYTE
bPackMethod;
// Packing Method
BYTE
bVoiceMode;
// mono or stereo
The header is followed immediately by Block Type 1.
Here is a discussion of various fields:
bBlockID
The Block Type identifier is 8.
nBlockLen
Length of the block (in bytes), excluding the
bBlockID
and
nBlockLen
fields.
The value is 4.
wTimeConstant
This is a 2-byte field which indicates the
Time Constant
of the digitized
sound data in the Block Type 1.
The calculation of the Time Constant is
the same as described on Block Type 1, but the whole word of the result
is stored here.
For a 44 100Hz sampling rate mono digitized sound, the Time Constant is
calculated as follows:
Time Constant
= 65536 - (256 000 000 / 44 100)
= 59732 (0E95H)