Gets wave header information for a given encoding value.

DWORD vceGetWaveInfo ( CTAHD ctahd,
unsigned encoding,
VCE_WAVE_INFO *waveinfo,
unsigned size)

ctahd Handle returned by ctaCreateContext.

encoding Encoding ID, e.g., VCE_ENCODE_NMS_24.

waveinfo Pointer to the buffer to receive the following VCE_WAVE_INFO structure:

typedef struct
{
 DWORD  size;
 WORD   format;
 WORD   nchannels;
 DWORD  samplespersec;
 DWORD  datarate;
 WORD   blocksize;
 DWORD  bitspersample;
} VCE_ WAVE_INFO;

The fields are described in the Details section.

size Size in bytes of the waveinfo buffer.

• SUCCESS
• CTAERR_BAD_SIZE
  size is less than the size of DWORD.
• CTAERR_NOT_FOUND
  No wave information found for specified encoding.
• CTAERR_INVALID_CTAHD

• None.

This function retrieves information from the Voice Message service's WAVE information table for a specified encoding. The Voice service maintains a table that maps encoding values to WAVE file header information. This is used by vceCreateFile to create a new WAVE file and by vceOpenFile to determine the encoding of the file. For more information about WAVE files, refer to the Microsoft Windows Multimedia Programmer's Reference.

The table initially contains compiled-in entries for known encodings. New entries may be added with vceSetWaveInfo.

The VCE_WAVE_INFO structure contains the following fields:

Field	Description
size	Size of the structure, in bytes. This is set to: sizeof (VCE_WAVE_INFO).
format	The WAVE format type as defined by Microsoft, for example, WAVE_FORMAT_PCM (defined in the Microsoft header file mmreg.h).
nchannels	The number of discrete channels in the format. Use 1 for mono and 2 for stereo.
samplespersec	The sample rate in samples per second.
datarate	Average bytes per second.
blockalign	The minimum block size of the data. For PCM data, the block size is the number of bytes in a single sample.
bitspersample	Number of bits per sample.

vceCreateFile, vceOpenFile, vceSetWaveInfo

/* Display contents of wave info table */
/* Sample output:
  *
  * Encoding  Wave Type  M/S  SampleRate  DataRate  Block Bits
  * ----------------------------------------------------------
  *    1         56   M       8000         2100     42   2
  */

void myShowWaveInfo (CTAHD ctahd)
{
  unsigned      encoding;
  VCE_WAVE_INFO waveinfo;

  printf("Encoding  Wave Type  M/S" "  SampleRate  DataRate  Block Bits\n");
    printf("------------------------" "---------------------------------\n");
  for (encoding = 0; encoding < 256; encoding ++)
  {
  if (vceGetWaveInfo(ctahd,encoding,&waveinfo,sizeof waveinfo)!= SUCCESS)
            continue;
        printf("    %3d        %3d   %c" "     %6d       %6d     %3d  %2d\n",
               encoding,
               waveinfo.format,
               waveinfo.nchannels == 1 ? 'M' : 'S',
               waveinfo.samplespersec,
               waveinfo.datarate,
               waveinfo.blocksize,
               waveinfo.bitspersample); }
}

Encoding  Wave Type  M/S  SampleRate  DataRate  Block Bits
----------------------------------------------------------
   1         56   M       8000         2100     42   2
   2         56   M       8000         3100     62   3
   3         56   M       8000         4100     82   4
   4         56   M       8000         8200    162   8
  10          7   M       8000         8000      1   8
  11          6   M       8000         8000      1   8
  13          1   M       8000        16000      2  16
  14         23   M       6000         3000      1   4
  15         23   M       8000         4000      1   4
  16          1   M      11025        11025      1   8
  17          1   M      11025        22050      2  16
  22         17   M       6000         6600    244   4
  23         17   M       8000         8800    244   4