Mega Code Archive
Determine the length of a wave file
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type
EMyMCIException = class(Exception);
var
FDeviceID: Word;
MyError, dwFlags: Longint;
procedure TForm1.GetWaveLength;
var
WaveLen: DWORD;
begin
OpenMedia('C:\Hickory.wav');
SetMediaTimeFormat;
WaveLen := GetMediaStatus(MCI_STATUS_LENGTH);
CloseMedia;
Form1.label1.Caption := IntToStr(WaveLen) + 'mS';
end;
procedure TForm1.OpenMedia(FileName: string);
var
MyOpenParms: TMCI_Open_Parms;
begin
with MyOpenParms do
begin
dwCallback := Handle; // TForm1.Handle
lpstrDeviceType := PChar('WaveAudio');
lpstrElementName := PChar(FileName);
end; {with MyOpenParms}
dwFlags := MCI_WAIT or MCI_OPEN_ELEMENT or MCI_OPEN_TYPE;
MyError := mciSendCommand(0, MCI_OPEN, dwFlags, Longint(@MyOpenParms));
// one could use mciSendCommand(DevId, etc here to specify a particular
device
if MyError = 0 then
FDeviceID := MyOpenParms.wDeviceID
else
raise EMyMCIException.Create('Open Failed');
end;
procedure TForm1.SetMediaTimeFormat;
var
MySetParms: TMCI_Set_Parms;
begin
if FDeviceID <> 0 then
begin
dwFlags := MCI_WAIT or MCI_SET_TIME_FORMAT;
MySetParms.dwCallback := Handle; // TForm1.Handle
MySetParms.dwTimeFormat := MCI_FORMAT_MILLISECONDS;
MyError := mciSendCommand(FDeviceID, MCI_SET, dwFlags,
Longint(@MySetParms));
if MyError <> 0 then
raise EMyMCIException.Create('Status Failed');
end;
end;
function TForm1.GetMediaStatus(StatusItem: DWORD): DWORD;
var
MyStatusParms: TMCI_Status_Parms;
begin
if FDeviceID <> 0 then
begin
dwFlags := MCI_WAIT or MCI_STATUS_ITEM;
MyStatusParms.dwCallback := Handle; // TForm1.Handle
MyStatusParms.dwItem := StatusItem;
MyError := mciSendCommand(FDeviceID, MCI_STATUS, dwFlags,
Longint(@MyStatusParms));
if MyError = 0 then
Result := MyStatusParms.dwReturn
else
begin
raise EMyMCIException.Create('Status Failed');
end;
end;
end;
procedure TForm1.CloseMedia;
var
MyGenParms: TMCI_Generic_Parms;
begin
if FDeviceID <> 0 then
begin
dwFlags := 0;
MyGenParms.dwCallback := Handle; // TForm1.Handle
MyError := mciSendCommand(FDeviceID, MCI_CLOSE, dwFlags,
Longint(@MyGenParms));
if MyError = 0 then
FDeviceID := 0
else
begin
raise EMyMCIException.Create('Close Failed');
end;
end;
end;
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