TrueSpeech® Co-Processor
PRELIMINARY/CONFIDENTIAL
Version: 1.18
Note: All wave formats except WAVE_FORMAT_PCM are required to include a fact chunk that gives the
time length of the data chunk expressed in the samples.
The general format for wave files consists of a 4-byte ASCII tag for each chunk (“fmt”, “data”). This is followed by
a 4-byte tag giving the length of the chunk (not including the 8-byte tag-length header), followed by the actual data
for the chunk. A wave file can contain many chunks in any order. An application must search for the chunks it is
interested in by skipping over other chunks that it does not understand. For example:
“RIFF”
“WAVE”
“test”
16
16 bytes of “test” chunk data
“fmt “
16
16 bytes of “fmt “ data
“data”
1024
1024 bytes of “data”
“more”
32
32 bytes of “more” data
Note: The case of the 4-byte ASCII tag is significant.
When an application encounters the tag “test”, it should read the next 4 bytes, which contain the length (16) of the
“test” chunk. The application should then move forward through the file 16 bytes. This will position the file at the
next chunk tag. The application should then read this tag and repeat the above process until it encounters the chunk
that it is looking for.
To play back a wave file, the application should first find the “fmt “ chunk and determine if it can handle the wave
format that it describes. Only then should the application search for the “data” chunk to obtain the actual waveform
data.
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All specifications are subject to change without prior notice.
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