操作 Wave 文件(8): 使用 TMediaPlayer 录制 wav 文件

TMediaPlayer 录音是基于一个已存在的 wav 文件, 上次建立空白 wav 的函数可派上用场了.

TMediaPlayer 的功能是基于 MCI 的, 都是该淘汰的东西了, 只是简单了解下.

接下来还要学习用 waveIn...系列函数录音、用 DirectSound 录音.

---

unit Unit1;



interface



uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, MPlayer, StdCtrls;



type

  TForm1 = class(TForm)

    MediaPlayer1: TMediaPlayer;

    Button1: TButton;

    Button2: TButton;

    procedure FormCreate(Sender: TObject);

    procedure Button1Click(Sender: TObject);

    procedure Button2Click(Sender: TObject);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



uses MMSystem;



//建立一个空白 Wave 文件的函数

function CreateWav(chan, freq, bit: Word; const FilePath: string): Boolean;

var

  h: HMMIO;

  ckiRiff, ckiFmt, ckiData: TMMCKInfo;

  fmt: TPCMWaveFormat;

begin

  ZeroMemory(@ckiRiff, SizeOf(TMMCKInfo));

  ckiRiff.cksize := 36;

  ckiRiff.fccType := mmioStringToFOURCC('WAVE', 0);



  ZeroMemory(@ckiFmt, SizeOf(TMMCKInfo));

  ckiFmt.ckid := mmioStringToFOURCC('fmt', 0);



  ZeroMemory(@ckiData, SizeOf(TMMCKInfo));

  ckiData.ckid := mmioStringToFOURCC('data', 0);



  fmt.wf.wFormatTag := WAVE_FORMAT_PCM;

  fmt.wf.nChannels := chan;

  fmt.wf.nSamplesPerSec := freq;

  fmt.wf.nAvgBytesPerSec := freq * chan * bit div 8;

  fmt.wf.nBlockAlign := chan * bit div 8;

  fmt.wBitsPerSample := bit;



  h := mmioOpen(PChar(FilePath), nil, MMIO_CREATE or MMIO_WRITE);

  if h = 0 then Exit(False);



  if (mmioCreateChunk(h, @ckiRiff, MMIO_CREATERIFF) = MMSYSERR_NOERROR) and

    (mmioCreateChunk(h, @ckiFmt, 0) = MMSYSERR_NOERROR) and

    (mmioWrite(h, PAnsiChar(@fmt), SizeOf(TPCMWaveFormat)) = SizeOf(TPCMWaveFormat)) and

    (mmioAscend(h, @ckiFmt, 0) = MMSYSERR_NOERROR) and

    (mmioCreateChunk(h, @ckiData, 0) = MMSYSERR_NOERROR) then Result := True;



  mmioClose(h, 0);

end;



//文件路径

const path = 'C:\Temp\Test.wav';



//开始录音

procedure TForm1.Button1Click(Sender: TObject);

begin

  CreateWav(2, 22050, 16, path);



  MediaPlayer1.FileName := path;

  MediaPlayer1.Open;

  MediaPlayer1.StartRecording;



  Button2.Enabled := True;

end;



//停止录音并播放

procedure TForm1.Button2Click(Sender: TObject);

begin

  MediaPlayer1.Stop;

  MediaPlayer1.Play;

end;



procedure TForm1.FormCreate(Sender: TObject);

begin

  MediaPlayer1.Visible := False;

  Button2.Enabled := FileExists(path);

end;



end.