怎样控制程序播放声音的大小

Question

在程序中怎样用TrackBar来控制音量大小

Answer 1

auxoutsetvolume 是控制CD音量的  
waveOutSetVolume 是控制波形的  
midiOutSetVolume 是控制FM或者是synthesizer
unit Volume; interface uses windows,mmsystem; type  
    Tvolume=record 
       left,right:word; // 取值范围 0--65535 
    end; procedure fillstruct(control:PMixerControl;var Cdetails:tMIXERCONTROLDETAILS); 
function getpeak(control:PMixerControl;var peak:integer):boolean; 
function setvolume(control:Pmixercontrol; volume:Tvolume):boolean; 
function getvolume(control:Pmixercontrol; volume:Tvolume):boolean; var 
    mcontrols:array of array of array of PMixerControl; //mixer的数组,单声卡可以不用 
    fmixerhandle:HMIXER;   //mixer的句柄 implementation procedure fillstruct(control:PMixerControl;var Cdetails:tMIXERCONTROLDETAILS); 
begin 
    Cdetails.cbStruct:=sizeof(cdetails); 
    cdetails.dwControlID:=Control.dwControlID; 
    cdetails.cbDetails:=sizeof(integer); 
    cdetails.hwndOwner:=0; 
end; function getpeak(control:PMixerControl;var peak:integer):boolean; 
var 
   details:TMixerControlDetailsSigned; 
   cdetails:tMIXERCONTROLDETAILS; 
begin 
    Result:=false; 
    if control.dwControlType<> mixercontrol_controltype_peakmeter then exit; 
    cdetails.cChannels:=1; 
    cdetails.paDetails:=@details; 
    fillstruct(control,cdetails); 
    result:=mixerGetControlDetails(fmixerhandle,@cdetails,MIXER_GETCONTROLDETAILSF_VALUE)=0; 
end; function setvolume(control:Pmixercontrol; volume:Tvolume):boolean; 
var 
    details:array[0..30] of integer; 
    cdetails:tMIXERCONTROLDETAILS; 
begin 
    fillstruct(control,cdetails); 
    cdetails.cChannels:=2; 
    cdetails.paDetails:=@details; 
    details[0]:=volume.left; 
    details[1]:=volume.right; 
    result:=mixerSetControlDetails(fmixerhandle,@cdetails,MIXER_GETCONTROLDETAILSF_VALUE)=0; 
    volume.left:=details[0]; 
    volume.right:=details[1]; 
end; function getvolume(control:Pmixercontrol; volume:Tvolume):boolean; 
var 
    details:array[0..30] of integer; 
    cdetails:tMIXERCONTROLDETAILS; 
begin 
    fillstruct(control,cdetails); 
    cdetails.cChannels:=2; 
    cdetails.paDetails:=@details; 
    result:=mixerGetControlDetails(fmixerhandle,@cdetails,MIXER_GETCONTROLDETAILSF_VALUE)=0; 
    volume.left:=details[0]; 
    volume.right:=details[1]; 
end; end. // 调用方法: 
procedure TForm1.Button1Click(Sender: TObject); 
var  s : Tvolume; 
     kz : Pmixercontrol; 
begin 
    new(kz); //<------------ 此处一定要分配内存 
kz.dwControlID := 0; 
s.left := 0; 
s.right := 0; 
try 
setvolume(kz,s); 
except 
end; 
freemem(kz); 
end; 

Answer 2

有没有简单的，我用了meaidplay空件