合并两个 Wav 文件流的函数 - 回复 "刘文强" 的问题

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;

type
TForm1 = class(TForm)
Button1: TButton;
Button2: TButton;
procedure FormCreate(Sender: TObject);
procedure FormDestroy(Sender: TObject);
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

uses MMSystem;

{合并两个 Wav 文件流的函数}
function ConWavStream(AWavStream1, AWavStream2: TStream; var ANewStream: TStream): Boolean;
type
TWavFormat = packed record
ChunkID: array[0..3] of AnsiChar;     {'RIFF'}
ChunkSize: Longword;                  {size-8}
Format: array[0..3] of AnsiChar;      {'WAVE'}
SubChunk1ID: array[0..3] of AnsiChar; {'fmt '}
SubChunk1Size: Longword;              {hex10}
AudioFormat: Word;                    {hex 01}
NumOfChannels: Word;                  {1 mono, 2 stereo}
SampleRate: Longword;                 {number of samples/sec}
ByteRate: Longword;                   {samplerate* num of channels*bytes per (mono) sample}
BytesperSample: Word;                 {size of (mono) sample}
BitsPerSample: Word;                  {BytesperSample *8}
SubChunk2ID: array[0..3] of AnsiChar; {'data'}
SubChunk2Size: Longword;              {number of data bytes}
end;
var
vWavFormat1: TWavFormat;
vWavFormat2: TWavFormat;
vChunkSize1, vChunkSize2: Integer;
begin
Result := False;
if AWavStream1.Read(vWavFormat1, SizeOf(TWavFormat)) <> SizeOf(TWavFormat) then Exit;
if AWavStream2.Read(vWavFormat2, SizeOf(TWavFormat)) <> SizeOf(TWavFormat) then Exit;
if vWavFormat1.ChunkID <> 'RIFF' then Exit;
if vWavFormat1.SubChunk2ID <> 'data' then Exit;
vChunkSize1 := vWavFormat1.SubChunk2Size;
vChunkSize2 := vWavFormat2.SubChunk2Size;
vWavFormat1.ChunkSize := 0;
vWavFormat1.SubChunk2Size := 0;
vWavFormat2.ChunkSize := 0;
vWavFormat2.SubChunk2Size := 0;
if not CompareMem(@vWavFormat1, @vWavFormat2, SizeOf(TWavFormat)) then Exit; {格式不同}

vWavFormat1.ChunkSize := vChunkSize1 + vChunkSize2 + SizeOf(vWavFormat1) - 8;
vWavFormat1.SubChunk2Size := vChunkSize1 + vChunkSize2;
ANewStream.Write(vWavFormat1, SizeOf(TWavFormat));
ANewStream.CopyFrom(AWavStream1, vChunkSize1);
ANewStream.CopyFrom(AWavStream2, vChunkSize2);

Result := True;
end; { ConWavStream End}

var
WavStream: TStream;

{合并两个资源流; 之前要在资源中分别加载两个 WAV 文件, 并分别命名: wav1、wav2}
procedure TForm1.FormCreate(Sender: TObject);
var
rs1,rs2: TResourceStream;
begin
rs1 := TResourceStream.Create(HInstance, 'wav1', RT_RCDATA);
rs2 := TResourceStream.Create(HInstance, 'wav2', RT_RCDATA);
WavStream := TMemoryStream.Create;
ConWavStream(rs1, rs2, WavStream);
rs1.Free;
rs2.Free;
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
WavStream.Free;
end;

{循环播放}
procedure TForm1.Button1Click(Sender: TObject);
begin
sndPlaySound(TMemoryStream(WavStream).Memory, SND_ASYNC or SND_MEMORY or SND_LOOP);
end;

{暂停}
procedure TForm1.Button2Click(Sender: TObject);
begin
sndPlaySound(nil, 0);
end;

end.