Solved

RenderFile() , wide char paramater

Posted on 2004-08-25
15
348 Views
Last Modified: 2012-06-27
MSDN shows the following example for rendering a file in a filter graph:

hr = pGraph->RenderFile(L"C:\\Media\\Example.avi", 0);

my existing code manages movie filenames as LPCTSTR values. I have in place a placeholder method:

DWORD CImageView::LoadMovie(LPCTSTR a_lpszMovieName)

how can I cast my LPCTSTR movie name into something that RenderFile can use? Is that 'L' a macro of some type like _T ?

thanks
-Paul
0
Comment
Question by:PMH4514
  • 8
  • 7
15 Comments
 
LVL 86

Accepted Solution

by:
jkr earned 50 total points
ID: 11896384
You'll need to convert it to UNICODE, either by using

DWORD CImageView::LoadMovie(LPCTSTR a_lpszMovieName) {

    USES_CONVERSION:

    wchar_t* pwszMovieName = A2C ( a_lpszMovieName);
}

or using 'mbstowcs()' directly, e.g.


int nLen = strlen ( a_lpszMovieName);
wchar_t* pwsz = new wchar_t [ nLen];

mbstowcs ( pwsz, (LPTSTR) str, nLen);

hr = pGraph->RenderFile(pwsz, 0);

delete [] pwsz;

0
 

Author Comment

by:PMH4514
ID: 11896505
I'm wondering if there is anything about C++ that you *don't* know jkr????

thank you! You have been an invaluable resource to me :)

-Paul
0
 
LVL 86

Expert Comment

by:jkr
ID: 11896536
>> I'm wondering if there is anything about C++ that you *don't* know

Yes, actually a couple of things :o)
0
VMware Disaster Recovery and Data Protection

In this expert guide, you’ll learn about the components of a Modern Data Center. You will use cases for the value-added capabilities of Veeam®, including combining backup and replication for VMware disaster recovery and using replication for data center migration.

 

Author Comment

by:PMH4514
ID: 11896563
>>Yes, actually a couple of things :o)
I'll do my best to stump ya :)

hmm.. ok, that works now! but.. damn, I'm missing something or this is too good to be true.. (and this should probably be a new thread) - but Render(..) and then IMediaControl -> Run() pops my AVI open in a window..

I need it to render in a designated space within my prop-sheet.
0
 

Author Comment

by:PMH4514
ID: 11896574
oh and your code should be:
    mbstowcs ( pwsz, (LPTSTR) a_lpszMovieName, nLen);
not       
    mbstowcs ( pwsz, (LPTSTR) str, nLen);

0
 
LVL 86

Expert Comment

by:jkr
ID: 11896624
Yup, you are right :o)
0
 

Author Comment

by:PMH4514
ID: 11896646
hmm.. actually I'm still having a problem with that.
a_lpszMovieName = "e:\images\p1\data\20040825\movies\Cap1_Movie001.AVI"

when I run your code:
      int nLen = strlen ( a_lpszMovieName);
      wchar_t* pwsz = new wchar_t [ nLen];
      mbstowcs ( pwsz, (LPTSTR) a_lpszMovieName, nLen);

and put pwsz in the variable watcher, I see a base address and it expands to "101"

when I then do: g_pGraph->RenderFile(pwsz, 0);  I get an error that it can't find the file.

I first tried your :

   USES_CONVERSION:
    wchar_t* pwszMovieName = A2C ( a_lpszMovieName);

but the compiler didn't know what A2C was..




0
 
LVL 86

Expert Comment

by:jkr
ID: 11896757
Are you using the above *literally*, i.e. *without* double backslashes?
0
 

Author Comment

by:PMH4514
ID: 11896809
yeah, the a_lpszMovieName  is passed in with single backslashes..
0
 
LVL 86

Expert Comment

by:jkr
ID: 11896880
OK, if it is passed in, that should be OK. I think I spotted the problem, it should be

int nLen = strlen ( a_lpszMovieName) + 1;
0
 

Author Comment

by:PMH4514
ID: 11896972
cool.. that did it.

what is A2C and why didn't my compiler know what it is?
0
 
LVL 86

Expert Comment

by:jkr
ID: 11897126
A2C is a macro used by ATL and lives in "atlconv.h".
0
 

Author Comment

by:PMH4514
ID: 11897223
thanks-
0
 
LVL 86

Expert Comment

by:jkr
ID: 11897325
Ooops, that thing should have been A2W in the first place :-(
0
 

Author Comment

by:PMH4514
ID: 11898107
I forgive you :)
0

Featured Post

Master Your Team's Linux and Cloud Stack

Come see why top tech companies like Mailchimp and Media Temple use Linux Academy to build their employee training programs.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

When writing generic code, using template meta-programming techniques, it is sometimes useful to know if a type is convertible to another type. A good example of when this might be is if you are writing diagnostic instrumentation for code to generat…
Often, when implementing a feature, you won't know how certain events should be handled at the point where they occur and you'd rather defer to the user of your function or class. For example, a XML parser will extract a tag from the source code, wh…
The viewer will learn how to pass data into a function in C++. This is one step further in using functions. Instead of only printing text onto the console, the function will be able to perform calculations with argumentents given by the user.
The viewer will learn additional member functions of the vector class. Specifically, the capacity and swap member functions will be introduced.

803 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question