[PD] pix_video and dv1394 capture on Dapper/Edgy/FC6

Ivica Ico Bukvic ico.bukvic at gmail.com
Sun Dec 31 05:12:53 CET 2006


Well, here are my latest findings. I just spent 2 days trying to hack the
dvgrab app (available from Kino, talks to devices via userland) and somehow
merge it with Gem. I am pleased to report that the hackathon was successful
but the results were surprisingly the same as before (talk about the DOH!
moment). However, I did discover that actually both before and now the video
feed *was* working. It is however as if the entire texture in Gem is
covering either really small area (i.e. one pixel) or had some kind of
mangled data that remained for the most part black. How do I know this? When
I flickered with my hand in front of the camera and/or made drastic changes
in lighting/exposure, there was slight change in color of the overall
texture. 

So what gives? It obviously is not the way Gem tries to open devices as this
other userland model had no effect on the final results, but there is simply
something that prevents the texture to be projected properly. Granted, I
reused as much of the old code as possible but the core of the engine was
going through dvgrab which in and of itself works flawlessly.

So, given that Dapper/Edgy/FC6 all suffer from this (all of whom are new
distros), is it:

1) udev (unlikely since devices open ok)
2) updated fw driver which somehow messes something up (unlikely since Kino
works)
3) way how Gem talks to fw devices (unlikely since it apparently works)
4) something with imageStruct or some other GL-texture related thing
(unlikely since 0.90 release behaves the same)
5) something else but what?

The only obvious commonality is that all distros are new. Other than that, I
have no clue whatsoever...

At this point I am also wondering if Linux Gem and more specifically dv part
of it is actively maintained and if so by whom? Furthermore, I would love to
hear from others who are using Gem/DV in their work in order to figure out
whether this affects any other recent distro/setup.

If anyone is interested in testing this other hacked version I'll gladly
post it but please note that it is built with scotch tape and chewing gum.

Naturally, I am hoping for some help in this area since I am at a loss what
may be wrong...

Best wishes,

Ico






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