video4linux - wine

[Jasper van Veghel]

Rob Shearman wrote:
> Mike McCormack wrote:
> 
> >
> >There's currently no support, but you could add it via the Still Image 
> >(STI) API.  It's meant for scanners and webcams.  There's probably a 
> >way to add VFW (Video For Windows drivers) too.
> >
> >I have written an IDL file for IStillImage, which I haven't gotten 
> >round to submitting as yet.  I've attached it incase you're 
> >interested... I think it still needs some fixing up.
> >
> >Mike
> >
> >
> >MediaHost (TM) wrote:
> >
> >>Question: Is there support for video4linux devices with wine? Is 
> >>there some support for webcams? What are the settings (config)? I 
> >>couldn't find anything useful on google concerning this issue....
> >
> 
> You're probably much better off implementing a DirectShow -> V4L filter, 
> especially if you want to capture movies or sound.
> 
> Rob
>

I've recently been looking into VFW with Wine, and though I certainly am no
expert at the Windows API concerning this (first time I really looked into DX),
nor Wine for that matter, I was able to get a bit further from where I started,
so allow me to share my experiences with you.

As an application to test this stuff with I went for MSN 6.2, though certainly
not the best application for this, it seemed neat to finally have Webcam support
on MSN - I eventually got some of it working with a load of native DLLs, some
hacking on the SSL stuff (I ended up simply setting useSSL = false, the applica-
tion was sending plain-text over an SSL socket, which wasn't working; this fixed
things, or at least for this application ;-)) and adding some undocumented flag
to InternetSetOption (optionId = 87) - anyway, it seems that MSN is using some-
thing along the lines of the following webcam class I found using Google -
indeed, using a DirectShow filter:

http://www.jolash.com/projects/other_projects/webcam/WebCam.h

For things to start working under Wine I used the following native DLLs, which
I also registered with regsvr32 (for CLSIDs etc.)

COMCTL32.DLL
urlmon.dll
CRYPT32.DLL MSOSS.DLL
oleaut32.dll ole32.dll rpcrt4.dll
MSVCRT.DLL
shlwapi.dll shdocvw.dll
MLANG.DLL
qcap.dll amstream.dll

Though I'm not sure if amstream is needed. Don't know what qcap does as I only
managed to get to a point where something in qcap was called which was then
being forwarded to Quartz (IAMStreamConfig, for which I added a bunch of stubs
and semi-stubs (filled in some bogus information for VIDEO_STREAM_CONFIG_CAPS,
VIDEOINFOHEADER and AM_MEDIA_TYPE)

It turned out that, at least MSN, and this webcam class too, uses devenum to
find the video input devices (CLSID_VideoInputDeviceCategory), for which I've
added the proper code to CreateSpecialCategories and hence CreateClassEnumerator
(it also seems that the windows DLL of devenum always recreates the dynamic
registery entries whereas Wine only seems to add them once and then never again,
that is, once they're in the registry they stay there (hence if a new audio card
gets added to the system ..)) The Windows DLL seemed to be using avicap32 to
collect information on the available video input devices, so I've simply had
capGetDriverDescription return some string with a fictional video driver (this
also makes it possible to use a native devenum.dll) Next up is Quartz, which
seemed to want IAMStreamConfig (collecting information on the video stream (res,
depth, sps, ..) for starters, but I never got around to implementing enough of
that for the program to accept it and move on, so that's where I got stuck. It
may also have had something to do with MSN wanting an IKsPin which isn't imple-
mented (which is why native quartz may have failed, when trying to approach the
kernel in some way) Here's a small scenario of what I observed working with both
native and hacked up DLLs ;-)

DEVENUM - Read all VideoInputDeviceRenderer's (from CLSID)
DEVENUM - BindToObject() --> VfwCapture
QCAP    - BindToClass --> Quartz(VideoRenderer)
QUARTZ  - VideoRenderer_create
QUARTZ  - [FAIL] InputPin_QueryInterface (IKsPin)
QUARTS  - VideoRenderer_QueryInterface (IAMStreamConfig)

Anyway, the 'patches' I wrote are probably not worth much as the whole under-
taking was more of a little endeavor trying to see how far I go (MSN actually
managed to sign in, by the way, but kept crashing a few seconds after that (the
webcam stuff can be accessed without signing in though, there's a preview option
in one of the menus), but perhaps this brief explanation of my steps will prove
useful for someone wanting to implement this aspect of VFW :-) Perhaps someone
could build a control from the class I mentioned earlier which can then be used
for testing (through the webpage that refers to it says it's missing some code;
but at least it's a starting point)

Jasper
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