C / C++ / MFC

1-Jun-06 20:29

I am able to load(AfxLoadLibrary) the libavcodec dll in a VC7 Dialog based application. However I dont know how to call the functions within this DLL to encode/decode video. Has anybody done anything of this sort?

Hamid_RT1-Jun-06 20:37

1-Jun-06 20:37

GetProcAddress for get the address of a function

whitesky

RahulOP1-Jun-06 21:08

1-Jun-06 21:08

Ok, the def file says "avcodec_register_all @ 97 ; " so how would I use this with GetProcAddress?

"GetProcAddress(hModule, avcodec_register_all);" ??

Some kinda code snippets would be really helpful

Thanks anyway for replying

Hamid_RT1-Jun-06 21:31

Re: FFMPEG(Libavcodec DLL)+VC++ [modified]

1-Jun-06 21:31

I can explain for you how to use but i think better that you see this link Step by Step: Calling C++ DLLs from VC++ and[^]

whitesky

RahulOP1-Jun-06 22:43

Re: FFMPEG(Libavcodec DLL)+VC++ [modified]

1-Jun-06 22:43

I have already had a look at that. But am unsure about the typedef thingy. Plus i am using the AfxLoadLibrary option.
This is what I am trying and it builds and executes fine

HMODULE hmodule;<br />
hmodule = AfxLoadLibrary("libavcodec.dll");<br />
    if (!AfxLoadLibrary(_T("libavcodec.dll")))<br />
       // return 1;<br />
	   AfxMessageBox("failed to load");<br />
	typedef void * (__stdcall *avcodec_register_all)();<br />
GetProcAddress(hmodule,"avcodec_register_all");<br />
void * objptr= avcodec_register_all();

I know this will sound dumb but if I wanted to encode video, I will have to typedef every function that I call fm the DLL?
-- modified at 4:45 Friday 2nd June, 2006

Hamid_RT2-Jun-06 1:10

Re: FFMPEG(Libavcodec DLL)+VC++ [modified]

2-Jun-06 1:10

i write a sample i hope that helpful to you

<br />
/*   in dll file<br />
extern "C" BSTR FAR PASCAL EXPORT TestFunction(HWND hWnd,TCHAR lpt[50])<br />
{<br />
AFX_MANAGE_STATE(AfxGetStaticModuleState());<br />
BSTR		 Returnbstr;<br />
...<br />
...<br />
return Returnbstr;<br />
}<br />
*/<br />
<br />
//////////////Include file//////////////////<br />
typedef BSTR FAR  (WINAPI *TESTFUNCTION)(HWND hWnd,TCHAR lpt[50]);<br />
	TESTFUNCTION		    m_TestFunction;<br />
<br />
/////////////Cpp file///////////////////////////////<br />
	LibraryDll=LoadLibrary("Testdll.dll");<br />
<br />
	m_TestFunction=(TESTFUNCTION)GetProcAddress(LibraryDll,"TestFunction");//function in dll file<br />
<br />
	m_TestFunction(pWnd->m_hWnd,NULL);

whitesky

RahulOP4-Jun-06 18:36

4-Jun-06 18:36

Thank you for the code Smile | :)

But i am looking for code specific to FFMPEG and the libavcodec dll. Sigh | :sigh:

Any takers??

Hamid_RT4-Jun-06 22:24

4-Jun-06 22:24

I write one example for you but i dont know whats your dll(exactly) Smile | :)

whitesky

RahulOP4-Jun-06 22:38

4-Jun-06 22:38

You can learn more about FFMPEG from http://ffmpeg.mplayerhq.hu/[^]

Basically its an Audio/Video encoding/decoding thingy (OpenSource).You get dlls when you build ffmpeg and I am trying to use these DLLs in my VC++ application.Unfortunately, since its OpenSource, there isnt much documentation available online. Thanks for all your help though Big Grin | :-D

Hamid_RT4-Jun-06 22:54

4-Jun-06 22:54

Thanks for link Smile | :)

but where your dll that has problem(exactly address)
and if you need to decode and encode you can see codeproject examples

whitesky

RahulOP4-Jun-06 22:57

4-Jun-06 22:57

My dll has no problem. its in trying to use the functions of the dll that I get stuck . I dont know how to do it Frown | :-(

Sorry for not having made that clear sooner.

Hamid_RT4-Jun-06 23:02

4-Jun-06 23:02

ohh yes.ok wheres this dll file and also documets it

whitesky

RahulOP4-Jun-06 23:12

4-Jun-06 23:12

You can download FFMPEG from http://ffmpeg.mplayerhq.hu/download.html[^]. It can be built using MINGW and MinSys
Instructions here
http://soenkerohde.com/tutorials/ffmpeg/

Or you can directly download a pre-built version of FFMPEG that has the dlls and the exe ready. The dll also has a def file but that's hardly helped since it mentions what functions are there but not the paramters Frown | :-(

Device context trouble

shivditya1-Jun-06 20:29

shivditya

1-Jun-06 20:29

I am stuck in device context trouble.
Right now I am conclusion it will be worth to get directly
desktop dc for generic class.
If any body can suggest me way for passing device context to generic class
through thread function or getting desktop dc directly for drawing in generic class.

Here simulate is generic class and the nextpos function is doing lot of drawing stuff.and it needs device context,I have developed SDI application.
and used CView as base.

UINT CMy5CYLINDERView::ThreadFunc(LPVOID pParam)
{
CWnd *cwnd,*cwnd1;
cwnd1 = cwnd->GetWindow(1);
CDC* pDC = cwnd1->GetDC();
simulate* eng = (simulate*)pParam;
eng->nextpos(pDC);
// eng->nextpos(pszWindow);
return 0;

}

void CMy5CYLINDERView::support()
{
for(int ii = 0;ii <= 3;ii++)
{
x[ii] = AfxBeginThread(ThreadFunc,(LPVOID)&engine[ii]);

}
}.

|| ART OF LIVING ||

Hamid_RT1-Jun-06 20:43

1-Jun-06 20:43

whats value cwnd(initialize)
i guess your problem is cwnd1 = cwnd->GetWindow(1);

whitesky

shivditya1-Jun-06 21:10

shivditya

1-Jun-06 21:10

I tried solutions you given that day but it didnot worked.
How to get the window

CDC* pDC;// = this->GetDC();
HWND hwnd = ::GetActiveWindow();
HDC hdc = ::GetDC(hwnd);
pDC->SetOutputDC(hdc);
nextpos(pDC);

just now I tried longest path it also didnot worked.
I removed thread still I am able to get and pass the dc.
moment I assign anything to pDC it gives error

|| ART OF LIVING ||

Hamid_RT1-Jun-06 21:35

1-Jun-06 21:35

CDC* pDC without value so you get one error pDC=GetDC();
this line has error pDC->SetOutputDC(hdc);

whitesky

Re: program executing error

shivditya1-Jun-06 21:44

shivditya

1-Jun-06 21:44

Thanks friend i got my error.
I was calling this support fuction from the constructor before creation of window.
so it was unable to get the device context.now at least I got the dc.
now i am calling it though onlbuttondoubleclick.

As code for support I written much below the file inwhich I was saying this->getdc(),but the this pointer was not of the window.

|| ART OF LIVING ||

program executing error

Y_Kaushik1-Jun-06 19:53

Y_Kaushik

1-Jun-06 19:53

Hai all's
i have done the setting as givin below yet, i found again same problem
whenever executing the program
Could not execute the program Invalid (win32 error 267)
Check the directory settings from the Menu Tools>Options [Directories tab]
If it is incorrect put the correct value

Plz tell me where i am wrong

mailing me
Yogi

Hamid_RT1-Jun-06 20:12