[Gambas-devel] Webcam mods (Logitec Quickcam 4000 etc) :: testers wanted ...

[Benoit Minisini]

On vendredi 9 janvier 2009, Gareth Bult wrote:
> Hi,
>
> Attached is my version of CWebcam.c, if anyone can give this a try I would
> very much appreciate it. (against trunk)
>
> Issues;
>
> The current V4L2 assumes that the camera will return an RGB signal that it
> can stuff directly into a "Picture" or "Image" object. - not always the
> case, for example with the Logitec QuickCam 4000 (and I'm sure quite a few
> others) .
>
> As a result, a post-processor is required to convert from the Camera's
> format (in this case yuv420p) to RGB. I've inserted a hook so this (and
> possibly other) post-processing routines can be added. The actual
> conversion routine I've hijacked directly from "Camorama", pretty much no
> tweaking required.
>
> In addition and just to make life interesting, the VIDIOCGMBUF ioctl seems
> to be partially broken, not sure if it's specific to the driver for this
> camera or if it's a wider issue, however it seems to return a fixed buffer
> size and frame count, regardless of the resolution specified. For 320x240
> this is fine, two frames will fit in the allocated space and it works fine.
> However, for 640x480 it returns sufficient memory for 1 frame, but
> specifies two frames in the header - not good! (this breaks gambas pretty
> quickly) So I've included a fix to rewrite the "mbuf" field IF the contents
> are invalid, i.e. if the widthxheightxdepthxframes is greater than the
> allocated size.
>
> I'm hoping that none of this affects standard RGB cameras, again if someone
> could test I would appreciate it.
>
> If you drop this into the v4l/src directory and do a make install, if your
> Logitec wasn't working, running the webcam demo should now work.
>
> .. I'm new to hacking Gambas so if I've done something bad re; memory etc ,
> please let me know...
>
>
> Regards,
> Gareth.

Hi, Gareth:

I have completely redesigned the internal memory image management in Gambas 
since revision #1803.

Now there is a gb.image component that will centralize the most possible 
function about images. And, especially, the conversion between different 
image formats.

The image component can deal with 32 bits RGBA, RGB, BGR and BGRA formats 
only, but it can convert between more different formats.

Can you take a quick look at that component to see if the YUV conversion you 
inserted in the gb.v4l component worth being put in that component?

I have ported all components to this new design, and so CWebcam.c. Do you want 
a svn write access, so that you can commit your changes directly in it? I 
will have less work if I don't have to do it myself!

Regards,

-- 
Benoit Minisini