Waveform Data Block (WDB) structure

Libcwav provides a data structure for describing the various waveform properties called a Waveform Data Block and defined as: 

     typedef struct {
         short           format;
         short           file_type;
         short           smplbits;
         unsigned short  sample_rate;
         short           ref_level;
         short           n_segments;
         short           n_per_rec;
         float           scale;
         float           bias;
         short           error;
     } WDB;

When existing files are opened, the WDB structure is set by the open waveform function opnwav(). when a new file is to be created. The structure should be initialized by the application program and passed to opnwav(). The elements of a WDB are:

WDB.format
Binary format of data in file. Possible values:
O8_format
8 bit Offset Binary
OB_format
12 bit Offset Binary
PC_format
16 bit Twos Complement
TC_format
12 bit Twos Complement
GT_format
Generic Twos Complement (bits per sample in WDB.smplbits)
GO_format
Generic Offset Binary (bits per sample in WDB.smplbits)

WDB.file_type
Storage format of the waveform in file. Possible values:
RIFF
A waveform file format using the standard IBM/Microsoft Resource Interchange File Format (RIFF).
ASEL
A waveform file using the ASEL internal storage format

WDB.smplbits
Number of bits per sample. (1-16) Only needed for formats GT_format and GO_format.

WDB.sample_rate
The sample rate in Hz.

WDB.n_segments
Number of segments defined in file, (only applicable for existing waveforms.) See wavgst for a description of segment tables.

WDB.n_per_rec
Total channels of data (i.e. samples) per record.

WDB.scale
Together with WDB.bias allows linear scaling from integer sample values to real-world coordinates. Sample values are intended to be transformed as:
real_value = WDB.scale * sample_value + WDB.bias;

WDB.bias
The intercept for linear transformation of sample values to real-world values.

WDB.error
One of the following constants will be returned by opnwav if an error occurs in opening a file:
NO_FILE
File could not be found or created
INVALID_FORMAT
Format not one of those defined
NO_SEGMENT
Segment not found in file
INVALID_CHANNEL
Channel number > total channels per record
INSUF_MEMORY
Memory allocation failure
INSUF_BUFFER
Predefined buffer too small for record.
INVALID_FILE
File neither RIFF nor ASEL format.

SEE ALSO

opnwav(),
Libcwav library

AUTHOR

Shirley Peters, H.T.Bunnell