DirectShow and VB

[Dean Earley]

Has anyone made any progress with using DirectShow (for video capture) with VB easily yet?

Ray Mercers DX page looks like it was last updated in 99!

Thanks

--
Dean Earley (dean.earley@icode.co.uk)
i-Catcher Development Team

iCode Systems

[Sujit Liddle]

Hi Dean,
I'm struggling too. I came across an interesting approach. The application
has a helper application which runs on startup which hogs all the filters it
needs so that no other application can access them. This makes sure that the
required filters are available when the actual application is run.
Sujit

"Dean Earley" <dean.earley@icode.co.uk> wrote in message
news:3e034fc4@tnews.web.devx.com...
> Has anyone made any progress with using DirectShow (for video capture)
with VB easily yet?
>
> Ray Mercers DX page looks like it was last updated in 99!
>
> Thanks
>
> --
> Dean Earley (dean.earley@icode.co.uk)
> i-Catcher Development Team
>
> iCode Systems
>
>

[Ray Mercer]

"Dean Earley" <dean.earley@icode.co.uk> wrote in message
news:3e034fc4@tnews.web.devx.com...
> Has anyone made any progress with using DirectShow (for video capture)
with VB easily yet?
>
> Ray Mercers DX page looks like it was last updated in 99!

Well, now that DirectX 9 is released (
http://www.microsoft.com/windows/directx/default.asp ) I guess I can
publicly state that MS has decided to add NO support for vidcap from VB (or
C#) to DX9. MS has *never* supported capture with DirectShow for VB -
despite what developers (including myself) have asked for. This is the main
reason why I haven't updated the DX info on my site since 1999. I don't
believe they have any intention of supporting video (or audio) capture from
VB in the future either. VB helped make Win32 the success it is today - but
MS has decided that VB developers aren't interested in multimedia and
video/audio capture going forward. If you think this is a bad decision,
then tell them so - but it is quite doubtful whether they will listen.
mswish@microsoft.com subject: DirectShow

-Ray Mercer
www.shrinkwrapvb.com

[Mike D Sutton]

> hi group

Please post test messages to the "Test" group on this server, thank you..

Mike


-- EDais --

- Microsoft Visual Basic MVP -
WWW: Http://EDais.earlsoft.co.uk/
Work E-Mail: EDais@btclick.com
Other E-Mail: Mike.Sutton@btclick.com

[Sujit Liddle]

OK here's what I've got so far:

*Note: I'm trying with vfw drivers first because wdm drivers are far more
complex.
1. Not all vfw drivers work with direct show. Try different drivers and find
one which works. As a rule of thumb, if you can get GraphEdit to work with
the driver, it's probably OK. No sentimental attachments here: the 'Old
Faithful' driver you have used for years may well have to be discarded.
2. You have to build the graph 'blind'. GraphEdit is a big help: build the
graph in GraphEdit and test it out. Note down the names of the filters, the
pins they have, the order in which they are connected, etc. Now build the
exact same graph in your application, adding the required filters to the
filter graph and connecting the pins one by one. The VB IDE is not much use
here; there is very little by way of aids to help you complete the commands
like there is for other VB stuff.
3. I can't seem to figure out how to get the VFW dialogs like 'format' and
'source'. If anyone can, please post how to get at the interface from VB; I
would really like to be able to do this. The workaround is to initialise
the vfw driver to the desired state using another application (like the
utility that came with the capture card, or VirtualDub), or using the
standard vfw or avicap methods as perfected by Ray Mercer et. al.
Fortunately, most vfw drivers 'remember' their last settings, so you don't
need to re-initialise them when you access them through direct show.
4. A clean system is very important. Make sure no other capture cards and
drivers are present. Uninstalling the driver doesn't necessarily get rid of
the files that have been copied to the system folder, nor is the registry as
it was before you messed it up with a driver that you wanted to check out.
Some drivers will only work if the exact hardware( the capture card for
which the driver was written) is on your system. Others work only if the
software utility that came with the capture card is installed. I have
dedicated a hard disk to this development work and have had to format and
reinstall everything several times in the past few weeks.
5. On the plus side, specifying a particular compression codec is as simple
as connecting it to the graph when the graph is constructed. Again, you may
need to initialise the codec once after it is installed ( I use VirtualDub )
and every time you want to change its settings. I haven't tried to configure
it from VB directshow yet.
6. Clean up. It is very important to release all the interfaces and
resources you have allocated in your code. Failure to do this causes memory
hogging, 'access denied' errors, crashes and hang-ups. Restarts are often
needed to reset the hardware and vfw driver. Check often to see that the
driver is not locked in a non- functioning state ( use the utility that came
with the capture card, or VirtualDub), and restart your computer if so.

I have a feeling that time is running out for VFW. ref. my post: vfw driver
for SAA7130 dated 17-Jun-2002. We need to get serious about direct show and
find a way to use it in VB, or move on to another language.

Sujit Liddle

"Sujit Liddle" <sujit_liddle@hotmail.com> wrote in message
news:3e038abc@tnews.web.devx.com...
> Hi Dean,
> I'm struggling too. I came across an interesting approach. The application
> has a helper application which runs on startup which hogs all the filters
it
> needs so that no other application can access them. This makes sure that
the
> required filters are available when the actual application is run.
> Sujit
>
> "Dean Earley" <dean.earley@icode.co.uk> wrote in message
> news:3e034fc4@tnews.web.devx.com...
> > Has anyone made any progress with using DirectShow (for video capture)
> with VB easily yet?
> >
> > Ray Mercers DX page looks like it was last updated in 99!
> >
> > Thanks
> >
> > --
> > Dean Earley (dean.earley@icode.co.uk)
> > i-Catcher Development Team
> >
> > iCode Systems
> >
> >
>
>