操作 Wave 文件(15): 合并与剪裁 wav 文件

unit Unit1;



interface



uses

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

  Dialogs, StdCtrls;



type

  TForm1 = class(TForm)

    Button1: TButton;

    Button2: TButton;

    procedure Button1Click(Sender: TObject);

    procedure Button2Click(Sender: TObject);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



uses MMSystem;



//从指定 wav 文件中获取格式信息和波形数据的函数

function GetWaveFmtData(const path: string; var fmt: TWaveFormatEx; var buf: TBytes): Boolean;

var

  hFile: HMMIO;

  ckiRIFF,ckiFmt,ckiData: TMMCKInfo;

begin

  Result := False;

  hFile := mmioOpen(PChar(path), nil, MMIO_READ);

  if hFile = 0 then Exit;

  ZeroMemory(@ckiRIFF, SizeOf(TMMCKInfo));

  ZeroMemory(@ckiFmt, SizeOf(TMMCKInfo));

  ZeroMemory(@ckiData, SizeOf(TMMCKInfo));

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

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

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

  ZeroMemory(@fmt, SizeOf(TWaveFormatEx));

  mmioDescend(hFile, @ckiRIFF, nil, MMIO_FINDRIFF);

  if (ckiRIFF.ckid = FOURCC_RIFF) and (ckiRIFF.fccType = mmioStringToFOURCC('WAVE',0)) and

     (mmioDescend(hFile, @ckiFmt, @ckiRIFF, MMIO_FINDCHUNK) = MMSYSERR_NOERROR) and

     (mmioRead(hFile, @fmt, ckiFmt.cksize) = ckiFmt.cksize) and

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

     (mmioDescend(hFile, @ckiData, @ckiRIFF, MMIO_FINDCHUNK) = MMSYSERR_NOERROR) then

  begin

    SetLength(buf, ckiData.cksize);

    Result := (mmioRead(hFile, PAnsiChar(buf), ckiData.cksize) = ckiData.cksize);

  end;

  mmioClose(hFile, 0);

end;



//根据格式信息和波形数据建立 wav 文件的函数

function CreateWave(const path: string; const fmt: TWaveFormatEx; const buf: TBytes): Boolean;

var

  h: HMMIO;

  ckiRiff, ckiFmt, ckiData: TMMCKInfo;

begin

  ZeroMemory(@ckiRiff, SizeOf(TMMCKInfo));

  ckiRiff.cksize := 44 - 8 + Length(buf);

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



  ZeroMemory(@ckiFmt, SizeOf(TMMCKInfo));

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



  ZeroMemory(@ckiData, SizeOf(TMMCKInfo));

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

  ckiData.cksize := Length(buf);



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

  if (h <> 0) and (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 := (mmioWrite(h, PAnsiChar(buf), Length(buf)) = Length(buf));

  mmioClose(h, 0);

end;





//截取 wav 文件, 本例截留了文件的 1/4

procedure TForm1.Button1Click(Sender: TObject);

const

  pathSource = 'C:\WINDOWS\Media\Windows XP 启动.wav';

  pathDest = 'C:\Temp\New1.wav';

var

  fmt: TWaveFormatEx;

  buf: TBytes;

begin

  GetWaveFmtData(pathSource, fmt, buf);

  SetLength(buf, Length(buf) div 4);

  CreateWave(pathDest, fmt, buf);

end;



//合并 wav 文件

procedure TForm1.Button2Click(Sender: TObject);

const

  path1 = 'C:\WINDOWS\Media\Windows XP 启动.wav';

  path2 = 'C:\WINDOWS\Media\Windows XP 关机.wav';

  pathDest = 'C:\Temp\New2.wav';

var

  fmt1,fmt2: TWaveFormatEx;

  buf1,buf2: TBytes;

  oldLen: Integer;

begin

  GetWaveFmtData(path1, fmt1, buf1);

  GetWaveFmtData(path2, fmt2, buf2);



  if CompareMem(@fmt1, @fmt2, SizeOf(TWaveFormatEx)) then

  begin

    oldLen := Length(buf1);

    SetLength(buf1, Length(buf1) + Length(buf2));

    CopyMemory(@buf1[oldLen], Pointer(buf2), Length(buf2));

    CreateWave(pathDest, fmt1, buf1);

  end else ShowMessage('文件格式不一致, 没有执行合并!');

end;



end.