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POWhy does the webcam image appear darker than when it's started from another application?
 

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  1. POWhy does the webcam image appear darker than when it's started from another application?
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    <p>I am using the Windows API to take a picture with the attached webcam.</p> <p>All works fine except the picture captured is very dark. If I start the webcam in another application and then I capture with my application, all works fine. What am I doing wrong?</p> <p>Here is the code I use:</p> <pre><code>procedure TWebCam.Execute; //different thread var hand: THandle; fname: AnsiString; const WM_CAP_START = $0400; WM_CAP_DRIVER_CONNECT = $0400 + 10; WM_CAP_DRIVER_DISCONNECT = $0400 + 11; WM_CAP_SAVEDIB = $0400 + 25; WM_CAP_GRAB_FRAME = $0400 + 60; WM_CAP_STOP = $0400 + 68; WM_CAP_SET_PREVIEW = WM_CAP_START + 50; WM_CAP_SET_PREVIEWRATE = WM_CAP_START + 52; WM_CAP_SET_SCALE = WM_CAP_START + 53; begin FreeOnTerminate := True; fname := AnsiString(IncludeTrailingPathDelimiter(ExtractFilePath(ParamStr(0))) + 'capture.bmp'); if FileExists(String(fname)) then DeleteFile(string(fname)); hand := capCreateCaptureWindowA('CapWindow32', WS_CHILD and WS_VISIBLE, 0, 0, 0, 0, frmMain.Handle, 0); if hand &lt;&gt; 0 then begin if SendMessage(hand, WM_CAP_DRIVER_CONNECT, 0, 0) &lt;&gt; 0 then begin SendMessage(hand,WM_CAP_SET_PREVIEWRATE,66,0); //tried some stuff that are not required but without any success SendMessage(hand, WM_CAP_SET_PREVIEW, 1, 0); Sleep(5000); SendMessage(hand, WM_CAP_GRAB_FRAME, 0, 0); SendMessage(hand, WM_CAP_SAVEDIB, 0, NativeInt(PAnsichar(fname))); SendMessage(hand, WM_CAP_DRIVER_DISCONNECT, 0, 0); SendMessage(hand, $0010, 0, 0); SendMessage(frmMain.Handle,WM_USER + 24,0,0); //notify main thread end else begin SendMessage(hand, $0010, 0, 0); Synchronize(NoWebcam); end; end else Synchronize(NoWebcam); end; </code></pre>
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    2. VO
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    3. VO
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    1. COI think that after "WM_CAP_DRIVER_CONNECT" you need to send another message which will make the webcam's LED to shine (:
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      1. USComputerSaysNo
    2. CO@DorinDuminica eventual sa dea drumu la bec :))
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    3. CO@AndreasRejbrand det var ett skämt ... du är alltid kränkande och sarkastiska ... har du vänner?
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      1. POWhy does the webcam image appear darker than when it's started from another application?
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