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1991-12-12
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Digitized Voice Programmer's Toolkit for the PC
-----------------------------------------------
Version 2.0
Copyright (c) 1988,1989,1990,1991 Farpoint Software
Playback Procedure Call Documemtation
------------------------------------------------------------------------------
Calibration routine
-------------------
Prototype:
long pascal far PCALIBRATE(void);
This must be called once before PLAYVOICE is called. PLAYVOICE may be called
multiple times thereafter, as long as the program remains in memory.
Return value:
Low word Meaning
-------- -------
0 success
1 this CPU is too slow to accomplish normal-speed playback
2 operation not possible under Microsoft Windows
in "Enhanced" mode
3 unusual speaker drive circuit encountered,
might not output sound correctly
The return value high word is the actual speed calibration constant for this
computer. It should be 64 or higher for adequate sound quality; it should be
256 or higher for maximum quality. This number indicates the number of
discrete output waveform quantization steps available.
------------------------------------------------------------------------------
Force Calibration Routine
-------------------------
Prototype:
void pascal far PSETCAL(unsigned int calfactor);
Normally never used, this call can be used to set the internal calibration
constant normally determined by the PCALIBRATE routine. A possible use for
PSETCAL would be to alter the playback speed.
There is no return value.
------------------------------------------------------------------------------
Playback Routine
----------------
Prototype:
long pascal far PLAYVOICE(unsigned char far *buffer, long bytecount);
This routine actually performs the voice output. The CPU will be fully
occupied by this operation. The background mode of operation found in DVPT
version 1 was sacrificed in version 2 in order to achieve the improved sound
quality that you now hear. Any keypress during playback will terminate the
operation. The keystroke will still be in the BIOS keystroke buffer when
PLAYVOICE returns. Note that literally ANY keyboard action, including key
releases and shift keys, will be sufficient to end playback.
The pointer "buffer" passed to the routine will be treated as a huge pointer,
with 64k segment boundaries taken care of automatically. Also, the "bytecount"
parameter is a 32 bit number. Thus, the practical limit to the size of one
contiguous block of data to be played is the amount of memory available to
your program.
The return value indicates the actual number of bytes played. Unless
terminated by keyboard activity, this number will be equal to the "bytecount"
passed to the routine.