• 4.4.1. DX_XPB Parameters
• G.711 Voice Coder Support
• G.721 Voice Coder Support
• Linear PCM Voice Coder Support
• OKI ADPCM Voice Coder Support
• G.726 Voice Coder Support
• GSM Voice Coder Support
• TrueSpeech Voice Coder Support
• Example

4.4. Coder Enhancements

As discussed in Section 2.2.3. Basic Voice Features Supported, Play and Record functionality for additional coders is now included with Dialogic Voice Software. These coders are included with the player (dx_playiottdata( ) function) and recorder (dx_reciottdata( ) function) in the voice library.

4.4.1. DX_XPB Parameters

The DX_XPB structure specifies the file format, data format (coder), sampling rate, and resolution for all audio files associated with a DX_IOTT table. It is used by the following play and record functions: dx_playiottdata( ) and dx_reciottdata( ).

Parameter	Description
wFileFormat	Specifies one of the following audio file formats. Note that this field is ignored by the convenience functions dx_recwav( ), dx_recvox( ), and dx_playvox( ).
	FILE_FORMAT_VOX	Dialogic VOX file format
	FILE_FORMAT_WAVE	Microsoft WAVE file format
wDataFormat	Specifies one of the following data formats:
	DATA_FORMAT_DIALOGIC_ ADPCM	4-bit OKI ADPCM (Dialogic registered)
	DATA_FORMAT_MULAW or DATA_FORMAT_G711_ MULAW	8-bit mu-law G.711 PCM
	DATA_FORMAT_ALAW or DATA_FORMAT_G711_ ALAW	8-bit a-law G.711 PCM
	DATA_FORMAT_PCM	8-bit or 16-bit Linear PCM
	DATA_FORMAT_G721	G.721
	DATA_FORMAT_G726	G.726 bit-exact coder
	DATA_FORMAT_GSM610_ MICROSOFT	GSM 6.10 full-rate coder (Microsoft Windows compatible format)*
	DATA_FORMAT_GSM610_ TIPHON	GSM 6.10 VOX full-rate coder (TIPHON format)
	DATA_FORMAT_ TRUESPEECH	TrueSpeech data format
nSamplesPerSec	Specifies one of the following sampling rates:
	DRT_6KHZ	6 kHz sampling rate.
	DRT_8KHZ	8 kHz sampling rate.
	DRT_11KHZ	11 kHz sampling rate. Note: 11kHz OKI ADPCM is not supported.
wBitsPerSample	Specifies the number of bits per sample. This number varies with the data format. For more information, refer to the following sections on coder support.

*Microsoft Windows Media Recorder Audio Compression Codec: GSM 6.10 Audio CODEC

G.711 Voice Coder Support

The G.711 voice coder is supported through the following parameters in the DX_XPB structure:

Parameter	Possible Values
wFileFormat	FILE_FORMAT_WAV FILE_FORMAT_VOX
wDataFormat	DATA_FORMAT_G711_ALAW or DATA_FORMAT_ALAW
	DATA_FORMAT_G711_MULAW or DATA_FORMAT_MULAW
nSamplesPerSec	DRT_6KHZ DRT_8KHZ
wBitsPerSample	8 (48 Kb/s or 64 Kb/s)

G.721 Voice Coder Support

The G.721 voice coder is supported through the following parameters in the DX_XPB structure:

Parameter	Possible Values
wFileFormat	FILE_FORMAT_WAV FILE_FORMAT_VOX
wDataFormat	DATA_FORMAT_G721
nSamplesPerSec	DRT_8KHZ
wBitsPerSample	4 (32 Kb/s)

Linear PCM Voice Coder Support

The linear PCM voice coder is supported through the following parameters in the DX_XPB structure:

Parameter	Possible Values
wFileFormat	FILE_FORMAT_WAV FILE_FORMAT_VOX
wDataFormat	DATA_FORMAT_PCM
nSamplesPerSec	DRT_11KHZ
wBitsPerSample	8 (88 Kb/s) 16 (176 Kb/s)

OKI ADPCM Voice Coder Support

The OKI ADPCM voice coder is supported through the following parameters in the DX_XPB structure:

Parameter	Possible Values
wFileFormat	FILE_FORMAT_WAV FILE_FORMAT_VOX
wDataFormat	DATA_FORMAT_DIALOGIC_ADPCM
nSamplesPerSec	DRT_6KHZ DRT_8KHZ
wBitsPerSample	4 (24 Kb/s or 32 Kb/s)

G.726 Voice Coder Support

The G.726 voice coder is supported through the following parameters in the DX_XPB structure:

Parameter	Possible Values
wFileFormat	FILE_FORMAT_WAV FILE_FORMAT_VOX
wDataFormat	DATA_FORMAT_G726
nSamplesPerSec	DRT_8KHZ
wBitsPerSample	2, 3, 4, or 5 (16, 24, 32, or 40 Kb/s, respectively.)

GSM Voice Coder Support

The GSM voice coder is supported through the following parameters in the DX_XPB structure:

Parameter	Possible Values
wFileFormat	FILE_FORMAT_WAV (supported only with DATA_FORMAT_GSM610_MICROSOFT) FILE_FORMAT_VOX
wDataFormat	DATA_FORMAT_GSM610_MICROSOFT
	DATA_FORMAT_GSM610_TIPHON
nSamplesPerSec	DRT_8KHZ
wBitsPerSample	0 (13 Kb/s.)

TrueSpeech Voice Coder Support

The TrueSpeech voice coder is supported through the following parameters in the DX_XPB structure:

Parameter	Possible Values
wFileFormat	FILE_FORMAT_WAV FILE_FORMAT_VOX
wDataFormat	DATA_FORMAT_TRUESPEECH
nSamplesPerSec	DRT_8KHZ
wBitsPerSample	0 (8.5 Kb/s)

Example

Following is a sample of the values for G.726 in the DX_XPB structure:

wFileFormat:          FILE_FORMAT_VOX  
wDataFormat:          DATA_FORMAT_G726  
nSamplesPerSec:       DRT_8KHZ  
wBitsPerSample:       4

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