DirectShow video playback on Windows Mobile 5.0 using Visual Studio 2005

why dont you use windows media player?

mahesh1402:  thank you for your comment.  However the compile error is coming from this line:

pEvent->SetNotifyWindow((OAHWND)g_hwnd, WM_GRAPHNOTIFY, 0);

the specific compile error is:

syntax error:  missing ')' before ';'

if you look at the line that is causing the compile error, you will notice that syntactically it looks perfectly correct.  The parentheses are matched up.  This implies to me that whatever the compiler is replacing WM_GRAPHNOTIFY with (due to the #define line), is causing the syntax error.  The define line is:

#define WM_GRAPHNOTIFY  WM_APP + 1

I have no idea what the previous definition for "WM_APP" might be, but I'm assuming that it most include some kind of special character like a semicolon.  That's the only thing I can think of that would cause the syntax error at compile time--because the line looks perfectly syntactically correct to me.

Mikal613:  Thank you for your comment, however, as I stated in my original post:

"The Windows CE 5.0 OS Image that we will be using does NOT include the Windows Media Player or associated OCX, so that is not a possibility.  Right now I am leaning towards using the DirectShow library, which definitely WILL be available on my target device.  But I am not locked into DirectShow if I can find a better solution.  I am also considering licensing the third-party TCPMP player from CoreCodec, but our requirements seem so simple, theoretically, that I would prefer to avoid incurring additional third-party licensing and support costs if at all possible.  Especially in light of the fact that DirectShow is available for no extra cost as part of our OS platform."

I understand that WMP is included in the WinMobile 5.0 platform that I am using for testing, but that does me no good because it won't be available on my final target platform.

on another Note, TCPMP is a open source project isnt it?

also, try doing this:


pEvent->SetNotifyWindow((OAHWND)g_hwnd, (0x8000 + 1), 0);

TCPMP *used* to be an open source project, and technically I think they are still willing to provide source under certain circumstances, but they no longer make the source available in their download package.  I am under the impression that they are in the process of changing their licensing model.  I have sent them e-mail to try to get an idea of what their plans are for the licensing model, and what requirements they now have for acquiring the source, but I haven't heard back from them yet.  I expect that those folks are pretty darn busy and am not expecting them to be very responsive in getting back to me, which is one of the reasons I'm leaning towards rolling my own player instead of trying to integrate theirs.  It's a shame because I am confident that my company would be willing to pay them for some commercial support but it just doesn't seem likely that they are going to have the time or interest in that.

Thank you for the code suggestions, and especially for the info about the definition of WM_APP.  Your suggestions make a lot of sense, and those are some good clues as to how I can try to figure out what's wrong.  I will try them out and post any further info that I can glean.

sakuya_su, you are my hero :)

thanks to your help I solved a big part of my problem.  i am giving you at least 250 points of the 500 for this question.

unfortunately i am still having a problem, so i would like to ask a further question or two and see if you or anyone else can help before i "accept" a final answer.

The problem is, WM_APP was never being defined.  I thought that was supposed to happen from including <windows.h>, but apparently either I am wrong about that or it is different for WinCE/WinMobile than it is for other Win32 OS's.

so, for the time being, I changed:

#define WM_GRAPHNOTIFY  WM_APP + 1

to

#define WM_GRAPHNOTIFY  (0x8000 + 1)

and now my app compiles and deploys to the WinMobile5.0 emulator successfully.  Unfortunately, the program crashes on this line:

pGraph->RenderFile(L"\\mymovie.avi", NULL);

I get an exception window that reads:

Unhandled exception at 0x00011198 in DirectShowWM5_cpp_Win32.exe:
0xC0000005: Access violation reading location 0x00000000.

Forgive me if this is a stupid question but it's been a while since I've written C++ code, and I've *NEVER* written DirectShow code.  To me, the 0x00000000 instantly implies that I'm somehow trying to do something to a pointer that is set to NULL.  But I copied and pasted this code straight from Microsoft's sample code so I don't know how I could have screwed anything up.  I will be happy to paste my full source if it would be useful but it is pretty much EXACTLY the same as the sample code at the Microsoft URL in my first post in this thread.

The only thing that I could think of was that maybe the filepath that I was specifying was invalid, or that the DirectShow libraries installed on the emulator don't support the video format of my file.  So I've tried moving the file to different folders and adjusting my string accordingly, and I've tried several different file formats:  AVI, MPG, WMV.  I can successfully play the WMV file in the Windows Media Player that is installed in the emulator--but none of the other formats will play in WMP.

The fact that the WMV file will play in WMP implies in my mind that the required codecs for WMV are alive and well on the emulator... so I would think that the DirectShow code should be able to AT LEAST play a WMV file.  But I get the same exception with the "Access Violation 0x00000000" even with the WMV file.  I have the WMV file stored in the root directory of the emulator's filesystem so I don't see how I could possibly have the path string wrong in my code.

So here are my two questions for now:
1) Anybody know what file(s) i need to #include to get WM_APP defined?  I will poke through the .h files in the SDK and see if I can answer that question myself but any suggestions would be great.
2) Anyone familiar enough with DirectShow to have any idea why I am getting this "Accesss Violation 0x00000000" exception?  Where am I screwing up and leaving a pointer NULL?

sakuya_su, again, thanks so much for your help, i'm a lot closer now than i was before!!

apparently, if you use an Pocket PC you'll notice that there are only 3 format WMP can play on a PPC:
 - WMV... duh, its MS
 - Avi with either:
   1. Microsoft MPEG-4 V1 Encoder
   2. or the MS MPEG-4 V2 Encoder

if the code you called upon can actually play WMV< then the code is working? try converting ur Avi to a MPEG-4 Version2 avi file(its actually a WMV file but you can rename it to avi XD).

to do that, you can use the Windows Media Encoder (free)

as for the WM_APP...
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winui/winui/windowsuserinterface/windowing/messagesandmessagequeues/messagesandmessagequeuesreference/messagesandmessagequeuesmessages/wm_app.asp

it says its declared in winuser.h and includede in windows.h... but what the heck, if it dont work you can just define your own.

good luck

both the MS MPEG-4 V1 and V2 encoder actualy encodes to WMV by defualt, but it is possible to call those encoders with graphedit and attach them to a AVI Muxer, so you can get Avi files with those 2 codecs to play on WMP

Thanks for the info about WM_APP.  I'm not too concerned about that issue because I will either find the right header file, or just define it myself like you suggested.

My program still doesn't work though.  I tried a WMV file--that was the first format I tried since I assumed it was the most likely to work with Microsoft libraries.  It plays fine in the actual Windows Media Player application that was pre-installed on the PocketPC emulator.  But when I try to play it from my DirectShow program, my program still crashes on this line:

pGraph->RenderFile(L"\\mymovie.wmv", NULL);

It still gives me the same exception:

Unhandled exception at 0x00011198 in DirectShowWM5_cpp_Win32.exe:
0xC0000005: Access violation reading location 0x00000000.

The null pointer thing makes me think that there's something else wrong besides the file format--but I'm not sure...

yeah

RenderFile is:

pGraph->RenderFile(Path, NULL);

now, the problem with yours is... "\\myhomemovie.wmv" is not a valid path name.. as \\means a network path

try..

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


look at this:
http://msdn.microsoft.com/archive/default.asp?url=/archive/en-us/directx9_c/directx/htm/igraphbuilderrenderfile.asp

Thanks for spending so much of your time with me on this.

Two points in response to your last comment.

Point #1:  On a WinCE device, there is no "C:".  All file paths just start with "\\".  See the following URL's, which are basically just WinCE specific versions of the same docs you were looking at.

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wcemultimedia5/html/wce50conplayingthefile.asp

Note the comment:  "// Filenames on Windows CE start with a \\ instead of a drive letter."

and you can see it in their full code sample here.
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wcemultimedia5/html/wce50condirectshowsamplecode.asp

Point #2:  In the link that you just sent me, there are a ton of error codes that imply that if my file path or video file format was invalid, I would get an HRESULT return value with the appropriate error code for me to check against.  But I am never getting a return value at all--it is crashing with an exception before it ever has a chance to return anything.

and a network path on a WinCE device would look like this:

L"\\\\OtherComputerName\\FolderName\\FolderName"

just try a local file 1st, might be because network path dont work

I am trying a local file.  I don't even need the ability to support network files in my application.  The WMV file is stored in the root directory of the WinCE device.

L"\\MyMovie.wmv"  IS the windows CE equivalent of

L"C:\\MyMovie.wmv" on XP or other Win32.

Look at the comments in the code snippet at this URL:

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wcemultimedia5/html/wce50conplayingthefile.asp

IGraphBuilder *pGraph;
IMediaControl *pMediaControl;
CoCreateInstance(CLSID_FilterGraph, NULL, CLSCTX_INPROC,
                    IID_IGraphBuilder, (void **)&pGraph);
// Query for IMediaControl (not shown)
// Filenames on Windows CE start with a \\ instead of a drive letter.
pGraph->RenderFile(L"\\Hello_World.avi", NULL);
pMediaControl->Run();


The part I'm trying to draw your attention to is "Filenames on Windows CE start with a \\ instead of a drive letter."

put the file on a SD card etc, then try \SD Card\FILENAME?

i cannot see why this code does not work apart from that, soryy cant help you there :(

but i'll keep researching on it

please don't apologize, i greatly appreciate you spending so much of your time looking into it.

I have tried putting the file on the SD card, I've tried putting it in the "My Documents" folder, I've tried putting it in the "Temp" folder, and about 5 other places (always changing the PATH string in my RenderFile line accordingly, of course), and none of it has worked.

From the last url that you posted for me:

http://msdn.microsoft.com/archive/default.asp?url=/archive/en-us/directx9_c/directx/htm/igraphbuilderrenderfile.asp

look at the list of return values (HRESULT codes).  Notice that there are error codes listed for "NOT_FOUND", "UNKNOWN_FILE_TYPE", "INVALID_FILE_FORMAT", "INVALIDARG", "ABORT", "FAIL", etc.

so if the problem was that I got the path wrong, then I should just get back one of those error codes as a return value, instead of the program crashing with an unhandled exception.  So I don't think the file path is the problem.

If you want to see the exception yourself I will be happy to give you my source file, or you can copy and paste the code straight off of the Microsoft page.  The Windows Mobile 5.0 emulator is free, it comes with the Windows Mobile 5.0 SDK... but only works with Visual Studio 2005...

thank you..

maybe i should open up a new question so i can give you 500 more points :)  because you did answer my first one about WM_GRAPHNOTIFY...

Hello cprice404

What Mahesh1402 is saying is correct. Becaus as you say
*****************************
so, for the time being, I changed:
#define WM_GRAPHNOTIFY  WM_APP + 1
to
#define WM_GRAPHNOTIFY  (0x8000 + 1)

and now my app compiles and deploys to the WinMobile5.0 emulator successfully.  Unfortunately, the program crashes on this line:
******************************

Then the chances are that you havent defined the WM_APP is not defined at the time when the preprocessing is happening. so whats happening is WM_APP is not getting replaced with any value.

So go back and check the includes of WM_APP. Those shold be before the Microsoft Includes.
I guess you have used the code from

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wcedshow/html/_dxce_dshow_learning_when_an_event_occurs.asp

Then you need to check the above.

Good Luck

umahesh

About the include file for WM_APP
It is declared in Winuser.h, include Windows.h

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winui/winui/windowsuserinterface/windowing/messagesandmessagequeues/messagesandmessagequeuesreference/messagesandmessagequeuesmessages/wm_app.asp

Good Luck,
umahesh

i cant really test that code because i'm on linux XD.

But... if WM_APP wasnt defined.. then maybe you missed something else too..

try the code for Win32, see if u get that error, i'll be back tomorrow to test out some stuff

Thanks everyone, I think this is the right track here.  I think there is some stuff that is supposed to get defined when WM_APP is supposed to get defined that isn't, and that's probably why I'm crashing.

As for mahesh1402 and umahesh's comments about making sure the directx paths are before the microsoft include paths--I am not using anything from DirectX except for DirectShow, and with Visual Studio 2005 and WinMobile5.0 SDK, the DirectShow stuff is included in the WinMobile 5.0 SDK, so I never even had to install the DirectX SDK.  So all of my includes/libs for both Windows and DirectShow are coming from the same paths, which on my install happen to be:

includes: C:\Program Files\Windows CE Tools\wce500\Windows Mobile 5.0 Pocket PC SDK\Include\Armv4i
libs: C:\Program Filews\Windows CE Tools\wce500\Windows Mobile 5.0 Pocket PC SDK\lib\ARMV4I

Furthermore, I have checked and double checked my include paths, and I am positive that the first <windows.h> that it is finding is from the directory I mentioned above.  Looking through the windows.h file, I do see a line that says #include <winuser.h>.   Double checking the paths again, I am certain that the first "winuser.h" it would find is also in that same includes directory.

Inside <winuser.h> I see the line that is supposed to define WM_APP, but it is obviously never being reached, because my program won't compile if I try to make any reference to WM_APP.  Obviously there is an "ifdef" or "ifndef" somewhere that is preventing the compiler from reaching the "<winuser.h>" file, or inside of that file it's not reaching the "#define WM_APP" line.  I have looked at all of the "ifdef" and "ifndef" lines that encompass those, and I don't see any obvious reason why any of them would fail.

the includes in my .cpp file are in this order:

#include "stdafx.h"  // autogenerated by VS2005
#include "MyApp.h"  // autogenerated by VS2005
#include <windows.h>  // added by me because it is in the Microsoft WinCE DirectShow sample code
#include <streams.h>  // added my be because this is where the DirectShow definitions are

if anyone can give me any clues on how to figure out why winuser.h or WM_APP is not getting processed at compile time that would be very helpful...

I will try to do a Win32 version and see if anything different happens... unfortunately I have to install the Windows Platform SDK to get the DirectShow stuff for Win32, and I have found some posts on newsgroups and such that suggest that the latest Platform SDK DirectShow stuff doesn't work very well with VS2005.

thanks all for your help

ok i have some new info.  I started trying to do a Win32 version of this to see if that would give me any clues.

First of all, WM_APP gets set properly in the Win32 version, even though my include lines are exactly the same.  But the Win32 App still crashes on the same line.  So I'm almost positive that the WM_APP definition is not the problem--though I still don't know why WM_APP isn't getting defined in the WinCE version.

Playing around with the debugger on the Win32 version, I found a major clue.  The line that is crashing is this one:

pGraph->RenderFile(L"C:\\MyMovie.wmv", NULL);

The exception is a NULL pointer exception.  It finally occurred to me to check and see if "pGraph" was set to NULL for some reason... and bingo, it sure is.

So the next question is, why is pGraph set to NULL?  It is supposed to get initialized on the line directly preceding that, which is:

CoCreateInstance(CLSID_FilterGraph, NULL, CLSCTX_INPROC,
                IID_IGraphBuilder, (void **)&pGraph);

For some reason that line is leaving pGraph set to NULL.  I will read up on the docs of CoCreateInstance and see if I can get a return value with an error code or something, but I thought I'd go ahead and post this info in case it means something meaningful to any of you.

Changed the CoCreateInstance line to:

HRESULT result = CoCreateInstance(CLSID_FilterGraph, NULL, CLSCTX_INPROC,
                IID_IGraphBuilder, (void **)&pGraph);

the value of "result" gets set to:

0x800401f0 CoInitialize has not been called.

This sounds like Microsoft just left a few COM-related setup lines out of their sample code, and I have too little experience with COM to have known that they needed to be there.  I will keep poking through the docs, I think I should be able to figure it out now, but if anyone already knows what I'm missing, let me know.

Adding one line:

CoInitialize(NULL);

above the CoCreateInstance line fixes everything on the Win32 version.  The video plays successfully.

I went back into the WinCE version and made the same fix.  The program no longer crashes, it runs now... but it doesn't actually play the video.  Still looking through docs... any thoughts appreciated...

I have narrowed down the problem a little bit more.  I am now saving the HRESULT return value from the RenderFile command.  The value that it is set to after it fails to play the video is VFW_E_CANNOT_RENDER, which as I understand means that it can't find an appropriate filter/codec for this file format.  But the file in question is a WMV file.  If DirectShow can play ANYTHING it should be able to play WMV, shouldn't it?  I can play this same WMV file just fine in the Windows Media Player application on the emulator.  And Windows Media Player is built on DirectShow so why would I get this "CANNOT_RENDER" error?

I also tried changing the file path argument to RenderFile to an invalid path, intentionally, to see if I got the same error.  When I use an invalid file path, I get VFW_E_NOT_FOUND as my error code.  So I know that I have my file path correct when I am getting the CANNOT_RENDER error code--I just don't know why I am getting that error code.

Any clues?

hmm, can you check what codecs are used by that WMV?

Here is details about the video codec and renders supported in Windows CE5.0

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wcemultimedia5/html/wce50conaudiocodecsrenderers.asp

Good luck