我想生成并播放一个连续的声音,其中特定频率和幅度会随时间变化。我不想在声音之间有延迟。如何使用 Delphi 或 C++ Builder 实现这一点?
我想生成并播放一个连续的声音,其中特定频率和幅度会随时间变化。我不想在声音之间有延迟。如何使用 Delphi 或 C++ Builder 实现这一点?
program Project1;
{$APPTYPE CONSOLE}
uses
SysUtils, Windows, MMSystem;
type
TWaveformSample = integer; // signed 32-bit; -2147483648..2147483647
TWaveformSamples = packed array of TWaveformSample; // one channel
var
Samples: TWaveformSamples;
fmt: TWaveFormatEx;
procedure InitAudioSys;
begin
with fmt do
begin
wFormatTag := WAVE_FORMAT_PCM;
nChannels := 1;
nSamplesPerSec := 44100;
wBitsPerSample := 32;
nAvgBytesPerSec := nChannels * nSamplesPerSec * wBitsPerSample div 8;
nBlockAlign := nChannels * wBitsPerSample div 8;
cbSize := 0;
end;
end;
// Hz // msec
procedure CreatePureSineTone(const AFreq: integer; const ADuration: integer;
const AVolume: double { in [0, 1] });
var
i: Integer;
omega,
dt, t: double;
vol: double;
begin
omega := 2*Pi*AFreq;
dt := 1/fmt.nSamplesPerSec;
t := 0;
vol := MaxInt * AVolume;
SetLength(Samples, Round((ADuration / 1000) * fmt.nSamplesPerSec));
for i := 0 to high(Samples) do
begin
Samples[i] := round(vol*sin(omega*t));
t := t + dt;
end;
end;
procedure PlaySound;
var
wo: integer;
hdr: TWaveHdr;
begin
if Length(samples) = 0 then
begin
Writeln('Error: No audio has been created yet.');
Exit;
end;
if waveOutOpen(@wo, WAVE_MAPPER, @fmt, 0, 0, CALLBACK_NULL) = MMSYSERR_NOERROR then
try
ZeroMemory(@hdr, sizeof(hdr));
with hdr do
begin
lpData := @samples[0];
dwBufferLength := fmt.nChannels * Length(Samples) * sizeof(TWaveformSample);
dwFlags := 0;
end;
waveOutPrepareHeader(wo, @hdr, sizeof(hdr));
waveOutWrite(wo, @hdr, sizeof(hdr));
sleep(500);
while waveOutUnprepareHeader(wo, @hdr, sizeof(hdr)) = WAVERR_STILLPLAYING do
sleep(100);
finally
waveOutClose(wo);
end;
end;
begin
try
InitAudioSys;
CreatePureSineTone(400, 1000, 0.7);
PlaySound;
except
on E: Exception do
begin
Writeln(E.Classname, ': ', E.Message);
Readln;
end;
end;
end.
InitAudioSys;
CreatePureSineTone(400, 1000, 0.7);
PlaySound;
https://sourceforge.net/projects/delphiasiovst/
使用起来非常简单,不需要包含所有文件,从主文件开始添加其余文件,还可以看看示例。
最终就像OnSomeEvent/OnSomeBuffer一样容易
然后只需用浮点值填充一个数组即可。
记不住OnEvent的确切名称,但在示例中很容易找到。
另一件事是将某些组件设置为活动/启用状态,就这么简单。
ASIO的好处是延迟非常低,甚至可以降到50微秒或更低。
它需要一个适用于您的声音芯片的ASIO驱动程序。
ASIO = 音频流输入输出
由音频工程师设计的API!
可能没有比这更好的了!;)