what is the simpliest way to play sound from array data in delphi

Question

Is there any simple function? I am searching something like that

Play(@data, 44000, 100 {time});

Answer 1

I have worked quite a lot with PCM audio manipulation. I always use this function when playing short sequences of custom waveform audio data:

var
  PlaySoundStopper: PBoolean;
  SoundPlayerActive: boolean = false;

procedure PlaySound(const Sound: TASSound);
var
  hWave: HWAVEOUT;
  hdr: TWaveHdr;
  buf: PAnsiChar;
  fmt: TWaveFormatEx;
  i: Integer;
  n: Integer;
begin

  try

    with fmt do
    begin
      wFormatTag := WAVE_FORMAT_PCM;
      nChannels := length(Sound.Channels);
      nSamplesPerSec := Sound.SampleRate;
      wBitsPerSample := 32;
      nAvgBytesPerSec := nChannels * nSamplesPerSec * wBitsPerSample div 8;
      nBlockAlign := nChannels * wBitsPerSample div 8;
      cbSize := 0;
    end;

    GetMem(buf, fmt.nChannels * length(Sound.Channels[0]) * sizeof(TASWaveformSample));
    if length(Sound.Channels) = 1 then
      CopyMemory(buf, @(Sound.Channels[0, 0]), length(Sound.Channels[0]) * sizeof(TASWaveformSample))
    else
      for i := 0 to high(Sound.Channels[0]) do
        for n := 0 to high(Sound.Channels) do
          CopyMemory(buf + sizeof(TASWaveformSample) * (i * fmt.nChannels + n), @(Sound.Channels[n, i]), sizeof(TASWaveformSample));

    if waveOutOpen(@hWave, WAVE_MAPPER, @fmt, 0, 0, CALLBACK_NULL) <> MMSYSERR_NOERROR then
      raise Exception.Create('SoundPlayerThread.Execute: waveOutOpen failed: ' + SysErrorMessage(GetLastError));

    ZeroMemory(@hdr, sizeof(hdr));
    with hdr do
    begin
      lpData := buf;
      dwBufferLength := fmt.nChannels * length(Sound.Channels[0]) * sizeof(TASWaveformSample);
      dwFlags := 0;
    end;

    try

      SoundPlayerActive := true;

      waveOutPrepareHeader(hWave, @hdr, sizeof(hdr));
      waveOutWrite(hWave, @hdr, sizeof(hdr));
      sleep(500);

      while waveOutUnprepareHeader(hWave, @hdr, sizeof(hdr)) = WAVERR_STILLPLAYING do
        if PlaySoundStopper^ then
        begin
          waveOutPause(hWave);
          waveOutUnprepareHeader(hWave, @hdr, sizeof(hdr));
          break;
        end
        else
          sleep(100);

    finally
      SoundPlayerActive := false;
      waveOutClose(hWave);
      FreeMem(buf);
    end;

  except
    on E: Exception do MessageBox(0, PChar(E.ClassName + ': ' + E.Message), 'Sound Playback Error', MB_ICONERROR);
  end;
end;

where

type
  TASWaveformSample = integer; // signed 32-bit; -2147483648..2147483647
  TASWaveformSamples = packed array of TASWaveformSample; // one channel
  PASSound = ^TASSound;
  TASSound = record
    Channels: packed array of TASWaveformSamples;
    SampleRate: cardinal;
  end;

A perhaps better way, is to use a thread for the playing. Then I do

var
  OwnerForm: HWND; // = 0;
  SndSource: PASSound; // = nil;
  ThreadPlaying: boolean; // = false;

type
  TSoundPlayerThread = class(TThread)
  private
    { Private declarations }
  protected
    procedure Execute; override;
  end;

implemented as

procedure TSoundPlayerThread.Execute;
var
  hWave: HWAVEOUT;
  hdr: TWaveHdr;
  buf: PAnsiChar;
  fmt: TWaveFormatEx;
  i: Integer;
  n: Integer;
begin

  ThreadPlaying := true;
  try

   try

      if not Assigned(SndSource) then
        Exit;

      with fmt do
      begin
        wFormatTag := WAVE_FORMAT_PCM;
        nChannels := length(SndSource^.Channels);
        nSamplesPerSec := SndSource^.SampleRate;
        wBitsPerSample := 32;
        nAvgBytesPerSec := nChannels * nSamplesPerSec * wBitsPerSample div 8;
        nBlockAlign := nChannels * wBitsPerSample div 8;
        cbSize := 0;
      end;

      GetMem(buf, fmt.nChannels * length(SndSource^.Channels[0]) * sizeof(TASWaveformSample));
      if length(SndSource^.Channels) = 1 then
        CopyMemory(buf, @(SndSource^.Channels[0, 0]), length(SndSource^.Channels[0]) * sizeof(TASWaveformSample))
      else
        for i := 0 to high(SndSource^.Channels[0]) do
          for n := 0 to high(SndSource^.Channels) do
            CopyMemory(buf + sizeof(TASWaveformSample) * (i * fmt.nChannels + n), @(SndSource^.Channels[n, i]), sizeof(TASWaveformSample));

      if waveOutOpen(@hWave, WAVE_MAPPER, @fmt, 0, 0, CALLBACK_NULL) <> MMSYSERR_NOERROR then
        raise Exception.Create('SoundPlayerThread.Execute: waveOutOpen failed: ' + SysErrorMessage(GetLastError));

      ZeroMemory(@hdr, sizeof(hdr));
      with hdr do
      begin
        lpData := buf;
        dwBufferLength := fmt.nChannels * length(SndSource^.Channels[0]) * sizeof(TASWaveformSample);
        dwFlags := 0;
      end;

      waveOutPrepareHeader(hWave, @hdr, sizeof(hdr));
      waveOutWrite(hWave, @hdr, sizeof(hdr));
      sleep(500);

      while waveOutUnprepareHeader(hWave, @hdr, sizeof(hdr)) = WAVERR_STILLPLAYING do
      begin
        sleep(100);
        if Terminated then
          waveOutReset(hWave);
      end;

      waveOutClose(hWave);
      FreeMem(buf);

    except
      on E: Exception do MessageBox(0, PChar(E.ClassName + ': ' + E.Message), 'TSoundPlayerThread', MB_ICONERROR);
    end;

  finally
    ThreadPlaying := false;
  end;
end;