Hej udviklere
Denne kode virker kun under win 98, ikke under win 2000. Kan man få den til at virke under win 2000? Koden giver udslag i forhold til lyden. Her er koden:
Fejlen under win 2000 er en exception class:
"The control reference is invalid. (1025)"
<pre>
{
Every line going into and out of the mixer has a number of "controls"
associated with it. Some of those controls are "meters," which give
you a real-time value of the sound level on the corresponding line.
Not all lines have meter controls, and not all sound cards provide
support for meters.
Here's some code that will retrieve a handle to the meter attached to
the WaveOut source of the speaker line, if there is one:
}
uses
MMSystem;
procedure TForm1.Button1Click(Sender: TObject);
var
MixerControl: TMixerControl;
MixerControlDetails: TMixerControlDetails;
MixerControlDetailsSigned: TMixerControlDetailsSigned;
Mixer: THandle;
MixerLine: TMixerLine;
MixerLineControls: TMixerLineControls;
PeakMeter: DWORD;
Rslt: DWORD;
SourceCount: Cardinal;
WaveOut: DWORD;
I: Integer;
X: Integer;
Y: Integer;
begin
Rslt := mixerOpen(@Mixer, 0, 0, 0, 0);
if Rslt <> 0 then
raise Exception.CreateFmt('Can''t open mixer (%d)', [Rslt]);
FillChar(MixerLine, SizeOf(MixerLine), 0);
MixerLine.cbStruct := SizeOf(MixerLine);
MixerLine.dwComponentType := MIXERLINE_COMPONENTTYPE_DST_SPEAKERS;
Rslt := mixerGetLineInfo(Mixer, @MixerLine,
MIXER_GETLINEINFOF_COMPONENTTYPE);
if Rslt <> 0 then
raise Exception.CreateFmt('Can''t find speaker line (%d)', [Rslt]);
SourceCount := MixerLine.cConnections;
WaveOut := $FFFFFFFF;
for I := 0 to SourceCount - 1 do
begin
MixerLine.dwSource := I;
Rslt := mixerGetLineInfo(Mixer, @MixerLine,
MIXER_GETLINEINFOF_SOURCE);
if Rslt <> 0 then
raise Exception.CreateFmt('Can''t get source line (%d)', [Rslt]);
if MixerLine.dwComponentType = MIXERLINE_COMPONENTTYPE_SRC_WAVEOUT then
begin
WaveOut := MixerLine.dwLineId;
Break;
end;
end;
if WaveOut = $FFFFFFFF then
raise Exception.Create('Can''t find wave out device');
FillChar(MixerLineControls, SizeOf(MixerLineControls), 0);
with MixerLineControls do
begin
cbStruct := SizeOf(MixerLineControls);
dwLineId := WaveOut;
dwControlType := MIXERCONTROL_CONTROLTYPE_PEAKMETER;
cControls := 1;
cbmxctrl := SizeOf(TMixerControl);
pamxctrl := @MixerControl;
end;
Rslt := mixerGetLineControls(Mixer, @MixerLineControls,MIXER_GETLINECONTROLSF_ONEBYTYPE);
case Rslt of
MIXERR_INVALCONTROL : raise Exception.CreateFmt('The control reference is invalid. (%d)',[Rslt]);
MIXERR_INVALLINE : raise Exception.CreateFmt('The audio line reference is invalid. (%d)',[Rslt]);
MMSYSERR_BADDEVICEID : raise Exception.CreateFmt('The hmxobj parameter specifies an invalid device identifier. (%d)',[Rslt]);
MMSYSERR_INVALFLAG : raise Exception.CreateFmt('One or more flags are invalid. (%d)',[Rslt]);
MMSYSERR_INVALHANDLE : raise Exception.CreateFmt('The hmxobj parameter specifies an invalid handle. (%d)',[Rslt]);
MMSYSERR_INVALPARAM : raise Exception.CreateFmt('One or more parameters are invalid. (%d)',[Rslt]);
MMSYSERR_NODRIVER : raise Exception.CreateFmt('No mixer device is available for the object specified by hmxobj. (%d)',[Rslt]);
end;
// if Rslt <> 0 then
// raise Exception.CreateFmt('Can''t find peak meter control (%d)',[Rslt]);
PeakMeter := MixerControl.dwControlID;
// at this point, I have the meter control ID, so I can
// repeatedly query its value and plot the resulting data
// on a canvas
X := 0;
FillChar(MixerControlDetails, SizeOf(MixerControlDetails), 0);
with MixerControlDetails do
begin
cbStruct := SizeOf(MixerControlDetails);
dwControlId := PeakMeter;
cChannels := 1;
cbDetails := SizeOf(MixerControlDetailsSigned);
paDetails := @MixerControlDetailsSigned;
end;
repeat
Sleep(10);
Rslt := mixerGetControlDetails(Mixer, @MixerControlDetails,
MIXER_GETCONTROLDETAILSF_VALUE);
if Rslt <> 0 then
raise Exception.CreateFmt('Can''t get control details (%d)',
[Rslt]);
Application.ProcessMessages;
Inc(X);
Y := 300 - Round(300 * Abs(MixerControlDetailsSigned.lValue) / 32768);
with Canvas do
begin
MoveTo(X, 0);
Pen.Color := clBtnFace;
LineTo(X, 300);
Pen.Color := clWindowText;
LineTo(X, Y);
end;
until X > 500;
// don't forget to close the mixer handle when you're done
Rslt := mixerClose(Mixer);
if Rslt <> 0 then
raise Exception.CreateFmt('Can''t close mixer (%d)', [Rslt]);
end;
</pre>
Med venlig hilsen
Mikkel Bøg Clemmensen
mt.clemmensen@vip.cybercity.dk
[Redigeret d. 09/04-02 18:39:00 af Mikkel B. Clemmensen]