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Как вывести звук через звуковую карту?

01.01.2007
uses 
 
MMSystem;
 
type
 
TVolumeLevel = 0..127;
 
procedure
MakeSound(Frequency{Hz}, Duration{mSec}: Integer; Volume: TVolumeLevel);
 
{writes tone to memory and plays it}
var
 
WaveFormatEx: TWaveFormatEx;
  MS
: TMemoryStream;
  i
, TempInt, DataCount, RiffCount: integer;
 
SoundValue: byte;
  w
: double; // omega ( 2 * pi * frequency)
const
 
Mono: Word = $0001;
 
SampleRate: Integer = 11025; // 8000, 11025, 22050, or 44100
 
RiffId: string = 'RIFF';
 
WaveId: string = 'WAVE';
 
FmtId: string = 'fmt ';
 
DataId: string = 'data';
begin
 
if Frequency > (0.6 * SampleRate) then
 
begin
   
ShowMessage(Format('Sample rate of %d is too Low to play a tone of %dHz',
     
[SampleRate, Frequency]));
   
Exit;
 
end;
 
with WaveFormatEx do
 
begin
    wFormatTag
:= WAVE_FORMAT_PCM;
    nChannels
:= Mono;
    nSamplesPerSec
:= SampleRate;
    wBitsPerSample
:= $0008;
    nBlockAlign
:= (nChannels * wBitsPerSample) div 8;
    nAvgBytesPerSec
:= nSamplesPerSec * nBlockAlign;
    cbSize
:= 0;
 
end;
  MS
:= TMemoryStream.Create;
 
with MS do
 
begin
   
{Calculate length of sound data and of file data}
   
DataCount := (Duration * SampleRate) div 1000; // sound data
   
RiffCount := Length(WaveId) + Length(FmtId) + SizeOf(DWORD) +
     
SizeOf(TWaveFormatEx) + Length(DataId) + SizeOf(DWORD) + DataCount; // file data
   
{write out the wave header}
   
Write(RiffId[1], 4); // 'RIFF'
   
Write(RiffCount, SizeOf(DWORD)); // file data size
   
Write(WaveId[1], Length(WaveId)); // 'WAVE'
   
Write(FmtId[1], Length(FmtId)); // 'fmt '
   
TempInt := SizeOf(TWaveFormatEx);
   
Write(TempInt, SizeOf(DWORD)); // TWaveFormat data size
   
Write(WaveFormatEx, SizeOf(TWaveFormatEx)); // WaveFormatEx record
   
Write(DataId[1], Length(DataId)); // 'data'
   
Write(DataCount, SizeOf(DWORD)); // sound data size
   
{calculate and write out the tone signal} // now the data values
    w
:= 2 * Pi * Frequency; // omega
   
for i := 0 to DataCount - 1 do
   
begin
     
SoundValue := 127 + trunc(Volume * sin(i * w / SampleRate)); // wt = w * i / SampleRate
     
Write(SoundValue, SizeOf(Byte));
   
end;
   
{now play the sound}
    sndPlaySound
(MS.Memory, SND_MEMORY or SND_SYNC);
    MS
.Free;
 
end;
end;
 
// How to call the function:
 
procedure TForm1
.Button1Click(Sender: TObject);
begin
 
MakeSound(1200, 1000, 60);
end;

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