Delphi - 获取波幅

Question

我需要制作Delphi库/组件来获取当前播放的声音（它不播放我的应用程序，只是播放扬声器上的一般声音）返回数据（左声道和右声道的幅度）。目前我通过麦克风扫描来处理它。他正在寻找，我尝试了网上不同的VU表（Torry...），但它们与Win7及更高版本不兼容。有人知道解决方案吗？谢谢

Answer 1

不知道我是否理解正确，如果您的意思是如何获取默认播放设备的峰值表，您可以尝试以下操作：

unit Unit1;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Winapi.ActiveX, System.Win.ComObj, MMSystem,
  Vcl.ComCtrls, Vcl.ExtCtrls;

type
  EDATAFLOW = TOleEnum;
  EROLE = TOleEnum;

  IMMDevice = interface(IUnknown)
    ['{D666063F-1587-4E43-81F1-B948E807363F}']
    function Activate(const iid: TGUID; const dwClsCtx: UINT; const pActivationParams: PPropVariant; out ppInterface: IUnknown)
      : HRESULT; stdcall;
  end;

  IMMDeviceCollection = interface(IUnknown)
    ['{0BD7A1BE-7A1A-44DB-8397-CC5392387B5E}']
  end;

  IMMDeviceEnumerator = interface(IUnknown)
    ['{A95664D2-9614-4F35-A746-DE8DB63617E6}']
    function EnumAudioEndpoints(const dataFlow: EDATAFLOW; const dwStateMask: DWORD; out ppDevices: IMMDeviceCollection): HRESULT; stdcall;
    function GetDefaultAudioEndpoint(const dataFlow: EDATAFLOW; const role: EROLE; out ppEndpoint: IMMDevice): HRESULT; stdcall;
  end;

  IAudioMeterInformation = interface(IUnknown)
    ['{C02216F6-8C67-4B5B-9D00-D008E73E0064}']
    function GetPeakValue(out pfPeak: Single): HRESULT; stdcall;
    function GetMeteringChannelCount(out pnChannelCount: UINT): HRESULT; stdcall;
    function GetChannelsPeakValues(u32ChannelCount: UINT; out afPeakValues: pSingle): HRESULT; stdcall;
    function QueryHardwareSupport(out pdwHardwareSupportMask: UINT): HRESULT; stdcall;
  end;

  TForm1 = class(TForm)
    ProgressBar1: TProgressBar;
    Timer1: TTimer;
    procedure FormCreate(Sender: TObject);
    procedure Timer1Timer(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

const
  IID_IMMDeviceEnumerator: TGUID = '{A95664D2-9614-4F35-A746-DE8DB63617E6}';
  CLASS_IMMDeviceEnumerator: TGUID = '{BCDE0395-E52F-467C-8E3D-C4579291692E}';
  IID_IAudioMeterInformation: TGUID = '{C02216F6-8C67-4B5B-9D00-D008E73E0064}';
  eRender = $00000000;
  eConsole = $00000000;

var
  Form1: TForm1;
  peak: IAudioMeterInformation = nil;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);

var
  device: IMMDevice;
  deviceEnumerator: IMMDeviceEnumerator;
begin
  Timer1.Enabled := False;
  ProgressBar1.Max := 65535; 
  CoCreateInstance(CLASS_IMMDeviceEnumerator, nil, CLSCTX_ALL, IID_IMMDeviceEnumerator, deviceEnumerator);
  deviceEnumerator.GetDefaultAudioEndpoint(eRender, eConsole, device);
  device.Activate(IID_IAudioMeterInformation, CLSCTX_ALL, nil, IUnknown(peak));
  Timer1.Enabled := true;
end;

procedure TForm1.Timer1Timer(Sender: TObject);
var
  Temp: Single;
begin
  peak.GetPeakValue(Temp);
  ProgressBar1.position := Round(Temp * 65535);
end;

end.