C / C++ / MFC

Moak26-Feb-08 0:08

26-Feb-08 0:08

Maybe your are running out of socket objects. Again I am only guessing... it would be helpful to see source code and detailed error codes (WSAGetLastError).

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Johpoke29-Feb-08 21:55

Johpoke

29-Feb-08 21:55

If i call WSAGetLastError() after the connect function fails it returns a 0. I dont know what that suggests though... What other detailed error codes can i find in my program?

How would I convert the code i linked to above into a open connection type?

Or maybe there is some example code of open TCP connection on codeproject?

//Johannes

Moak29-Feb-08 22:52

29-Feb-08 22:52

Johpoke wrote:
If i call WSAGetLastError() after the connect function fails it returns a 0. I dont know what that suggests though... What other detailed error codes can i find in my program?

Morning Johannes, maybe the error occurs earlier in your source code, check function return codes.

Johpoke wrote:
How would I convert the code i linked to above into a open connection type?

Which code, sorry I don't understand what you mean.

/M

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Moak23-Feb-08 3:01

23-Feb-08 3:01

Hey, just a quick question about your requirements: Do you want to send 64 bytes from client to server without a response in regular intervalls... or the other way around where the server sends data to every incoming client?

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Johpoke23-Feb-08 3:06

Johpoke

23-Feb-08 3:06

The server (which binds to port 23) is listening to incoming clients, and as soon as one connects, it sends the 64 characters, and then disconects the client, waiting for a new one.

So the second way in you message.

But yea, the server doesnt need to know anything really, just send the string upon new client. (the server doesnt have any idea when i cleint is coming either (ie in what interval)

When i was testing it a few mins ago, the interval was Sleep(50);

Thanks!

//Johannes

Moak26-Feb-08 0:34

problems with cap and vfw

26-Feb-08 0:34

Hej, with this requirements I would use a design like this:

- server delivers data when a client connects or sends a (zero) byte
- server closes connection only if there's no activity for 3 seconds or network/send error
- server closes connection after a persistent connection stayed 60 seconds
- server has an upper limit of x incoming sockets (more will be ignored)

- clients stay connected and may request data repeatedly
- clients close connection in case of network/receive/send error
- clients close connection if the received data was not according to protocol
- clients automatically reconnect only if they have been sucessfully connected and identified a server in last attempt
- clients could do multiple reconnect attempts, but with a delay (e.g. 60 seconds) and an upper limit of x reconnect attempts

This should give you a fairly efficient use of TCP and clients do not flood the LAN by error. Since you are using the telnet port on your server you could also use newline as a delimiter, which allows you do test with a telnet client.

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cmos17-Feb-08 4:09

17-Feb-08 4:09

Hello,
i have problems connection my webcam. I usw the video for windows (vfw.h).
Sometimesit works, i can see the live view and sometimes it doesnt work.

I have a main dialog and a setup dialog. when i push "setup" my setup dialog appears.
There, the use can choose the driver. I get the drivers by

<br />
for(int i = 0; i < 9; i++)<br />
{<br />
    if(capGetDriverDescription(i,sName.GetBuffer(),sName.GetAllocLength(),<br />
                               sVersion.GetBuffe(),sVersion.GetAllocLength()))<br />
    {			<br />
        m_Drivers.Add(sName);				 <br />
    }<br />
}<br />

in my main dialog there is a picture control element.
with GetClientRect i get the rect of this control and
fix it with ScreenToClient(&rect);
After that the InitCamera function is called.

<br />
void CUSBCamera::InitCamera(HWND HParent, int iDriverID, DWORD dwWidth, DWORD dwHeight, CRect rect)<br />
{<br />
   m_hwndCap = capCreateCaptureWindow("USB-Camera",WS_CHILD | WS_VISIBLE,rect.TopLeft   <br />
   ().x,rect.TopLeft().y,rect.Width(),rect.Height(),m_ParentWindowHandle,999);<br />
<br />
   m_ParentWindowHandle  = HParent;	<br />
   m_iDriverID		= iDriverID;<br />
   m_dwWidth		= dwWidth;<br />
   m_dwHeight		= dwHeight;<br />
   m_Rect			= rect;<br />
  <br />
   capSetCallbackOnError(m_hwndCap, NULL);<br />
   capSetCallbackOnCapControl(m_hwndCap,NULL);<br />
   capSetCallbackOnStatus(m_hwndCap, NULL);   <br />
   capSetCallbackOnFrame(m_hwndCap, NULL); <br />
   capSetCallbackOnVideoStream(m_hwndCap, NULL);<br />
   capSetCallbackOnCapControl(m_hwndCap, NULL);		<br />
   capSetCallbackOnWaveStream(m_hwndCap, NULL);<br />
   capSetCallbackOnYield(m_hwndCap, NULL);<br />
}<br />

Finished that, the connect function is called

<br />
BOOL CUSBCamera::Connect(LPFRAME_CALLBACK_PROC lpFrameCallback, LPVOID userData)<br />
{		<br />
	// connect to driver<br />
	if(capDriverConnect(m_hwndCap,m_iDriverID) && m_iDriverID >= 0)<br />
	{<br />
		// set callbakc function<br />
		capSetCallbackOnFrame(m_hwndCap,lpFrameCallback);		<br />
		// set userdate to corresponding hwnd<br />
		capSetUserData(m_hwndCap,userData);<br />
	 <br />
		//// set video format<br />
		DWORD dwSize;					<br />
		dwSize = capGetVideoFormatSize(m_hwndCap);<br />
		// allocate memory for bitmapinfo structure<br />
		m_lpbi = (LPBITMAPINFO)malloc(sizeof(BITMAPINFO));		<br />
		<br />
	<br />
		capGetVideoFormat(m_hwndCap, m_lpbi, dwSize); <br />
		m_lpbi->bmiHeader.biWidth  = m_dwWidth;<br />
		m_lpbi->bmiHeader.biHeight = m_dwHeight;<br />
		<br />
		capSetVideoFormat(m_hwndCap,m_lpbi,dwSize);					<br />
<br />
		capDriverDisconnect(m_hwndCap);                   //?<br />
		capDriverConnect(m_hwndCap,m_iDriverID);          //?<br />
		<br />
		capPreviewRate(m_hwndCap,100);<br />
		capPreview(m_hwndCap,TRUE);<br />
<br />
<br />
	// free memory<br />
	free(m_lpbi);<br />
	}<br />
	else <br />
	{<br />
		::MessageBox(NULL,_T("Es ist ein Fehler aufgetreten"),_T("Fehler"),MB_OK);<br />
		::DestroyWindow(m_hwndCap);<br />
		return FALSE;<br />
	}<br />
	return TRUE;<br />
}<br />

My problem is, when i press update in my setup dialog i can choose just one driver.
Its the Windows WDM Capture (Win32).
Then i choose this driver press the apply button and i return back to the main dialog.
Well sometimes i see a picture from my webcam and sometimes its just black. i dont see anything.

Is there a certain order to initialize the camera ? And why do I have only just one driver in my list ? My graphicscard has a video in/out interface.

This makro capDlgVideoSource doestn work. With other applications i can connect to my webcam.
But with my try it's just a matter of luck getting access to it or not.
Well, one or two times it worked and i got this dialog. But choosing my webcam from the list
didnt change anything. Still had this black window i've created with capCreateCaptureWindow

If possible i want to avoid using the capDlgVideoSource dialog.

Please help me.

cmos17-Feb-08 5:02

17-Feb-08 5:02

Hello again
i found out something interesting (well, for me it is).
I started a new simple project using th vfw interface.
But this time i also used capDlgVideoSource.
This time i could choose between my webcam and my video in from graphicscard.
And it worked. I got the view from my webcam. The interesting thing is, if i
choose my ATI video in from the capDlgVideoSource Dialog, close this program
and choose a driver in the actually program i dont see anything. Everthing is black.
When i start the programm where i use capDlgVideoSource and choose my webcam, close the program
and then choose the driver from my actually program it works.

Is there anyway to choose the source without using this capDlgVideoSource ?
It seems just selecting the driver (Windows WDM Capture) isnt enough.

greetings

Mark Salsbery17-Feb-08 9:46

17-Feb-08 9:46

I'm not sure how this is going to work...

for(int i = 0; i < 9; i++)<br />
{<br />
if(capGetDriverDescription(i,sName.GetBuffer(),sName.GetAllocLength(),<br />
sVersion.GetBuffe(),sVersion.GetAllocLength()))<br />
    {			<br />
        m_Drivers.Add(sName);				 <br />
    }<br />
}

How large are your string buffers? Which gets called first - GetAllocLength() or GetBuffer()?
If you must use CString like this, I would recommend calling GetBuffer() first with an appropriate length.
You also must release the buffer before using it...

for(int i = 0; i < 9; i++)<br />
{<br />
   LPTSTR pNameStrBuff =

sName.GetBuffer(256);<br />

LPTSTR pVersionStrBuff =

sVersion.GetBuffer(256);<br />
<br />

BOOL fRet = capGetDriverDescription(i, pNameStrBuff, 256, pVersionStrBuff

,256);<br />
<br />

   sName.ReleaseBuffer();<br />

sVersion.ReleaseBuffer();

   if (fRet)<br />
   {			<br />
             m_Drivers.Add(sName);				 <br />
   }<br />

}

As far as getting the video to work - debug it. Check the return values from those calls.
Where is it failing?

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

cmos17-Feb-08 10:07

17-Feb-08 10:07

Hello thanks for your answer.
I dotn have problems getting the drivers. This always works.
And yes, i also use sName.GetBufferSetLength( ).

I found the problem but dont know how to solve it.
As i told in my first reply i said that i wrote another small dialog for testing.

<br />
m_sLiveview.GetWindowRect(&m_Rect);<br />
	ScreenToClient(&m_Rect);<br />
	m_hwndCap = capCreateCaptureWindow(_T("USB"),WS_CHILD|WS_VISIBLE,m_Rect.TopLeft().x,m_Rect.TopLeft().y,m_Rect.Width(),m_Rect.Height(),this->GetSafeHwnd(),999);<br />
<br />
//	char szDeviceName[80];<br />
//	char szDeviceVersion[80];<br />
	CString szDeviceName; szDeviceName.GetBufferSetLength(100);<br />
	CString szDeviceVersion; szDeviceVersion.GetBufferSetLength(100);<br />
	CAtlArray<cstring> List;<br />
<br />
	for (int wIndex = 0; wIndex < 10; wIndex++) <br />
	{<br />
		if (capGetDriverDescription (wIndex, szDeviceName.GetBuffer(), szDeviceName.GetAllocLength(), szDeviceVersion.GetBuffer(),szDeviceVersion.GetAllocLength()))<br />
	    {<br />
		    List.Add(szDeviceName);<br />
		}<br />
	} <br />
	<br />
	capDriverConnect(m_hwndCap,List.GetCount()-1);<br />
	CAPDRIVERCAPS caps;<br />
	capDriverGetCaps(m_hwndCap,&caps,sizeof(CAPDRIVERCAPS));<br />
	<br />
	CString sMCIName;<br />
	if (caps.fHasDlgVideoSource)<br />
	{<br />
		capDlgVideoSource(m_hwndCap); 				<br />
	}<br />
<br />
	capCaptureAbort(m_hwndCap);<br />
	capSetCallbackOnError(m_hwndCap,NULL);<br />
	capSetCallbackOnCapControl(m_hwndCap,NULL);<br />
	capSetCallbackOnStatus(m_hwndCap,NULL);<br />
	capSetCallbackOnFrame(m_hwndCap,FrameCallbackProc);<br />
	capSetCallbackOnVideoStream(m_hwndCap, NULL);<br />
	capSetUserData(m_hwndCap,NULL);	<br />
<br />
	capPreviewRate(m_hwndCap,150);<br />
	capPreview(m_hwndCap,TRUE);<br />
</cstring>

;

with this settings it works because i call the capDlgVideoSource makro. There I can choose between
my graphicscard input and my webcam. So i think i need a way to get the device names instead
of the driver name. Althouh i have to input device installed (graphicscard video input and webcam) i can only choose one Windows WDM Capture Driver.

I also checked out the capGetMCIDeviceName but this only gets the previously set MCI device name.

Do you understand my problem ?

greetings

Mark Salsbery17-Feb-08 10:21

17-Feb-08 10:21

Member 3509166 wrote:
So i think i need a way to get the device names instead
of the driver name

AFAIK there's no way from VFW. From VFW's point of view, there's just one driver - the
WDM driver wrapping (for VFW) the devices that don't have VFW-specific drivers (very few devices provide
VFW drivers anymore - they're pretty much obsolete).

I stopped using VFW long ago, so I never looked into it, but there may be a way to manipulate
the driver but it would be through WDM, not VFW.

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

cmos17-Feb-08 10:59

17-Feb-08 10:59

Hello Mark, thanks for your reply.
I've just read this at another forum. someone had the same problem as me.

this is a part from public paper from 1997
"An example of incomplete API functionality can be found in the video capture API. Although it is possible to set the video source using a dialog box displayed to the user by calling the capDlgVideoSource function, doing the same from within an application without user mediation is, as far as we know, impossible. "

if this is true, it has never been fixed.
My webcam works when i use the capDlgVideoSource dialog.
But i want it without this.
At this forum someone wrote that the wdm handles more devices. so for me that means i can connect to the driver but if i have more than one device theres no other way getting acces to my webcam using this cap dialog.

the cap functions seems really easy to handle for me

greetings,
Robert

Mark Salsbery17-Feb-08 13:06

Changing the height of a CstatusBar

17-Feb-08 13:06

I don't know what to tell you.

Support for VFW was dropped many years ago. It's still there to support
legacy applications and that's it.

Probably your only choices are:

1) let the user select the device from the diaolg. I've never seen a driver that didn't persist these
settings.

2) Use a more modern video acquisition method.

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Stan the man17-Feb-08 4:05

Stan the man

17-Feb-08 4:05

Hi.

Just curious if anyone knows an easy way to change the height of a CStatusBar?

Thanks in advance.

Stan the Man

Re: Changing the height of a CstatusBar

Iain Clarke, Warrior Programmer18-Feb-08 3:07

Iain Clarke, Warrior Programmer

18-Feb-08 3:07

Stan the man wrote:
an easy way

Move your chair closer?

I haven't tried the following, but if you use CStatusBar::GetStatusCtrl, you can then use CStatusCtrl::SetMinHeight, which sounds like it should help.

The msdn example for it has it being used in the OnCreate method of it's parent, which is before everything gets finally positioned, so probably a good time.

Iain.

Iain Clarke appearing in spite of being begged not to by ^CPallini.

Re: Changing the height of a CstatusBar

Stan the man18-Feb-08 3:19

Stan the man

18-Feb-08 3:19

Hi Iain.

That did it.

Thanks.

Stan the man

How can i use CFtpConnection object in asynchronous way ?

Yanshof17-Feb-08 3:22

Yanshof

17-Feb-08 3:22

Hi All,

I want to use CFtpConnection to download and upload some files to some server.
But i want to do it in asynchronous way.

What i mean is to give some function address and in the end of upload/download this function will be call.

How can i do it ?

Thanks.

Re: How can i use CFtpConnection object in asynchronous way ?

Mark Salsbery17-Feb-08 8:40