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  • 操作 Wave 文件(10): 输入输出设备与格式支持


    unit Unit1;
    
    interface
    
    uses
      Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
      Dialogs, StdCtrls;
    
    type
      TForm1 = class(TForm)
        ListBox1: TListBox;
        ListBox2: TListBox;
        Button1: TButton;
        Button2: TButton;
        procedure Button1Click(Sender: TObject);
        procedure Button2Click(Sender: TObject);
      end;
    
    var
      Form1: TForm1;
    
    implementation
    
    {$R *.dfm}
    
    uses MMSystem;
    
    //设备列表; 指定设备时经常使用 WAVE_MAPPER 参数, 这样会自动选用合适的设备.
    procedure TForm1.Button1Click(Sender: TObject);
    var
      i: Integer;
      waveOutCaps: TWaveOutCaps;
      waveInCaps: TWaveInCaps;
    begin
      ListBox1.Items.Add('音频输出设备列表:');
      for i := 0 to waveOutGetNumDevs do
      begin
        ZeroMemory(@waveOutCaps, SizeOf(TWaveOutCaps));
        waveOutGetDevCaps(i, @waveOutCaps, SizeOf(TWaveOutCaps));
        ListBox1.Items.Add(waveOutCaps.szPname);
      end;
    
      ListBox2.Items.Add('音频输入设备列表:');
      for i := 0 to waveInGetNumDevs do
      begin
        ZeroMemory(@waveInCaps, SizeOf(TWaveInCaps));
        waveOutGetDevCaps(i, @waveInCaps, SizeOf(TWaveInCaps));
        ListBox2.Items.Add(waveInCaps.szPname);
      end;
    end;
    
    //判断是否支持指定的 Wave 格式
    procedure TForm1.Button2Click(Sender: TObject);
    var
      fmt: TPCMWaveFormat;
    begin
      fmt.wf.wFormatTag := WAVE_FORMAT_PCM;
      fmt.wf.nChannels := 2;
      fmt.wf.nSamplesPerSec := 22050;
      fmt.wf.nAvgBytesPerSec := 88200;
      fmt.wf.nBlockAlign := 4;
      fmt.wBitsPerSample := 16;
    
      if waveOutOpen(nil, 0, PWaveFormatEx(@fmt), 0, 0, WAVE_FORMAT_QUERY) = 0 then
        ShowMessage('第一个输出设备支持此格式');
    
      if waveInOpen(nil, 0, PWaveFormatEx(@fmt), 0, 0, WAVE_FORMAT_QUERY) = 0 then
        ShowMessage('第一个输入设备支持此格式');
    end;
    
    end.
    

    有把格式支持的判断写成函数的, 如:

    function IsFormatSupported(fmt: Pointer; DeviceId: DWORD): Boolean;
    begin
      Result := (waveOutOpen(nil, DeviceId, PWaveFormatEx(fmt), 0, 0, WAVE_FORMAT_QUERY) = 0);
    end;
    
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  • 原文地址:https://www.cnblogs.com/del/p/1600698.html
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