Pemutar MP3 Sederhana: Volume

Artikel ini lanjutan dari artikel saya yang terdahulu: Pemutar MP3 Sederhana: Trackbar. Pada artikel kali ini, saya akan menambahkan kemampuan mengatur volume. Program saya membutuhkan unit MMDevApi.pas yang saya dapatkan dari delphiforfun.org. Silakan kopi unit tersebut dibawah ini dan simpan sebagai file text biasa dengan ekstensi .Pas

Unit MMDevApi.pas
unit MMDevAPI; interface uses Windows, ActiveX, ComObj; const CLASS_IMMDeviceEnumerator : TGUID = '{BCDE0395-E52F-467C-8E3D-C4579291692E}'; IID_IMMDeviceEnumerator : TGUID = '{A95664D2-9614-4F35-A746-DE8DB63617E6}'; IID_IMMDevice : TGUID = '{D666063F-1587-4E43-81F1-B948E807363F}'; IID_IMMDeviceCollection : TGUID = '{0BD7A1BE-7A1A-44DB-8397-CC5392387B5E}'; IID_IAudioEndpointVolume : TGUID = '{5CDF2C82-841E-4546-9722-0CF74078229A}'; IID_IAudioMeterInformation : TGUID = '{C02216F6-8C67-4B5B-9D00-D008E73E0064}'; IID_IAudioEndpointVolumeCallback : TGUID = '{657804FA-D6AD-4496-8A60-352752AF4F89}'; DEVICE_STATE_ACTIVE = $00000001; DEVICE_STATE_UNPLUGGED = $00000002; DEVICE_STATE_NOTPRESENT = $00000004; DEVICE_STATEMASK_ALL = $00000007; type EDataFlow = TOleEnum; const eRender = $00000000; eCapture = $00000001; eAll = $00000002; EDataFlow_enum_count = $00000003; type ERole = TOleEnum; const eConsole = $00000000; eMultimedia = $00000001; eCommunications = $00000002; ERole_enum_count = $00000003; type IAudioEndpointVolumeCallback = interface(IUnknown) ['{657804FA-D6AD-4496-8A60-352752AF4F89}'] end; IAudioEndpointVolume = interface(IUnknown) ['{5CDF2C82-841E-4546-9722-0CF74078229A}'] function RegisterControlChangeNotify(AudioEndPtVol: IAudioEndpointVolumeCallback): Integer; stdcall; function UnregisterControlChangeNotify(AudioEndPtVol: IAudioEndpointVolumeCallback): Integer; stdcall; function GetChannelCount(out PInteger): Integer; stdcall; function SetMasterVolumeLevel(fLevelDB: single; pguidEventContext: PGUID): Integer; stdcall; function SetMasterVolumeLevelScalar(fLevelDB: single; pguidEventContext: PGUID): Integer; stdcall; function GetMasterVolumeLevel(out fLevelDB: single): Integer; stdcall; function GetMasterVolumeLevelScaler(out fLevelDB: single): Integer; stdcall; function SetChannelVolumeLevel(nChannel: Integer; fLevelDB: double; pguidEventContext: PGUID): Integer; stdcall; function SetChannelVolumeLevelScalar(nChannel: Integer; fLevelDB: double; pguidEventContext: PGUID): Integer; stdcall; function GetChannelVolumeLevel(nChannel: Integer; out fLevelDB: double): Integer; stdcall; function GetChannelVolumeLevelScalar(nChannel: Integer; out fLevel: double): Integer; stdcall; function SetMute(bMute: Boolean; pguidEventContext: PGUID): Integer; stdcall; function GetMute(out bMute: Boolean): Integer; stdcall; function GetVolumeStepInfo(pnStep: Integer; out pnStepCount: Integer): Integer; stdcall; function VolumeStepUp(pguidEventContext: PGUID): Integer; stdcall; function VolumeStepDown(pguidEventContext: PGUID): Integer; stdcall; function QueryHardwareSupport(out pdwHardwareSupportMask): Integer; stdcall; function GetVolumeRange(out pflVolumeMindB: double; out pflVolumeMaxdB: double; out pflVolumeIncrementdB: double): Integer; stdcall; end; IAudioMeterInformation = interface(IUnknown) ['{C02216F6-8C67-4B5B-9D00-D008E73E0064}'] end; IPropertyStore = interface(IUnknown) end; IMMDevice = interface(IUnknown) ['{D666063F-1587-4E43-81F1-B948E807363F}'] function Activate(const refId: TGUID; dwClsCtx: DWORD; pActivationParams: PInteger; out pEndpointVolume: IAudioEndpointVolume): Hresult; stdCall; function OpenPropertyStore(stgmAccess: DWORD; out ppProperties: IPropertyStore): Hresult; stdcall; function GetId(out ppstrId: PLPWSTR): Hresult; stdcall; function GetState(out State: Integer): Hresult; stdcall; end; IMMDeviceCollection = interface(IUnknown) ['{0BD7A1BE-7A1A-44DB-8397-CC5392387B5E}'] end; IMMNotificationClient = interface(IUnknown) ['{7991EEC9-7E89-4D85-8390-6C703CEC60C0}'] end; IMMDeviceEnumerator = interface(IUnknown) ['{A95664D2-9614-4F35-A746-DE8DB63617E6}'] function EnumAudioEndpoints(dataFlow: EDataFlow; deviceState: SYSUINT; DevCollection: IMMDeviceCollection): Hresult; stdcall; function GetDefaultAudioEndpoint(EDF: SYSUINT; ER: SYSUINT; out Dev :IMMDevice ): Hresult; stdcall; function GetDevice(pwstrId: pointer; out Dev: IMMDevice): HResult; stdcall; function RegisterEndpointNotificationCallback(pClient: IMMNotificationClient): Hresult; stdcall; end; implementation end.

Sekarang mari kita buat layout seperti dibawah ini:

Dibandingkan layout program pada artikel terdahulu. Saya menambahkan satu Trackbar lagi untuk mengatur volume. Kita juga harus menambahkan di bagian unit MMDevPas dan ActiveX di bagian uses

Uses
MMDevApi, ActiveX,......

Saya mempersiapkan pemakaian pengaturan suara di Procedure PreparingSound yang dipanggil di FormCreate milik form.

procedure TMainForm.PreparingSound;
var
    deviceEnumerator: IMMDeviceEnumerator;
    defaultDevice: IMMDevice;
begin
    EndpointVolume:= nil;
    CoCreateInstance(

        CLASS_IMMDeviceEnumerator, 

       nil, 

      CLSCTX_INPROC_SERVER,      

      IID_IMMDeviceEnumerator, deviceEnumerator);

     deviceEnumerator.GetDefaultAudioEndpoint(

     eRender, eConsole, 

     defaultDevice);

     defaultDevice.Activate(

     IID_IAudioEndpointVolume, 

     CLSCTX_INPROC_SERVER, 

     nil, endpointVolume);
end;

Pengaturan Volume terlaksana, saat pengguna mengubah-ubah trackbar volume. Tambahkan kode berikut pada OnChange milik TrackBar2.

procedure TMainForm.TrackBar2Change(Sender: TObject);
var
    VolumeLevel: Single;
begin
    if endpointVolume = nil then Exit;
    with Trackbar2 do volumeLevel:= Position/max;
    endpointVolume.SetMasterVolumeLevelScalar(VolumeLevel, nil);
end;

Program Selengkapnya

unit Main; interface uses Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs, MPlayer, StdCtrls, ComCtrls, ExtCtrls, MMDevAPI, Activex; type TMainForm = class(TForm) BtnOpen: TButton; MediaPlayer1: TMediaPlayer; OpenDialog1: TOpenDialog; TrackBar1: TTrackBar; Timer1: TTimer; TrackBar2: TTrackBar; Label1: TLabel; procedure BtnOpenClick(Sender: TObject); procedure FormCreate(Sender: TObject); procedure MediaPlayer1Click(Sender: TObject; Button: TMPBtnType; var DoDefault: Boolean); procedure Timer1Timer(Sender: TObject); procedure TrackBar2Change(Sender: TObject); private procedure PreparingSound; public end; var MainForm: TMainForm; endpointVolume: IAudioEndpointVolume; implementation {$R *.DFM} procedure TMainForm.BtnOpenClick(Sender: TObject); begin if OpenDialog1.Execute then begin MediaPlayer1.Filename := OpenDialog1.Filename; MediaPlayer1.Open; end; end; procedure TMainForm.PreparingSound; var deviceEnumerator: IMMDeviceEnumerator; defaultDevice: IMMDevice; begin EndpointVolume:= nil; CoCreateInstance(CLASS_IMMDeviceEnumerator, nil, CLSCTX_INPROC_SERVER, IID_IMMDeviceEnumerator, deviceEnumerator); deviceEnumerator.GetDefaultAudioEndpoint(eRender, eConsole, defaultDevice); defaultDevice.Activate(IID_IAudioEndpointVolume, CLSCTX_INPROC_SERVER, nil, endpointVolume); end; procedure TMainForm.FormCreate(Sender: TObject); begin Trackbar2.Position := 5; PreparingSound; OpenDialog1.Filter := 'WAV files|*.WAV|AVI files|*.AVI|MIDI files|*.MID|MP3 files|*.MP3|'; OpenDialog1.DefaultExt := '*.mp3'; OpenDialog1.FilterIndex := 4; end; procedure TMainForm.MediaPlayer1Click(Sender: TObject; Button: TMPBtnType; var DoDefault: Boolean); begin if button = btPlay then begin trackbar1.Min := 0; trackbar1.Max := Mediaplayer1.Length; timer1.Enabled := TRUE; end; end; procedure TMainForm.Timer1Timer(Sender: TObject); begin trackbar1.Position := MediaPlayer1.Position; end; procedure TMainForm.TrackBar2Change(Sender: TObject); var VolumeLevel: Single; begin if endpointVolume = nil then Exit; with Trackbar2 do volumeLevel:= Position/max; endpointVolume.SetMasterVolumeLevelScalar(VolumeLevel, nil); end; end.

Pemutar MP3 Sederhana: Volume 2018-06-04T14:18:00+07:00 Rating: 4.5 Diposkan Oleh: Good Dreamer