[Gridflow-dev] [PD] gridflow with web-#camera (fwd)

Mathieu Bouchard matju at artengine.ca
Sat Jun 24 20:33:24 EDT 2006

---------- Forwarded message ----------
Date: Sat, 24 Jun 2006 20:29:49 -0400 (EDT)
From: Mathieu Bouchard <matju at artengine.ca>
To: Alexandre Castonguay <acastonguay at artengine.ca>
Cc: pd-list at iem.at
Subject: Re: [PD] gridflow with web-#camera

On Fri, 23 Jun 2006, Alexandre Castonguay wrote:

> I added a test patch in /doc/examples.

It was called webcam.pd. There's no /doc/examples in Gridflow's CVS: you added 
it in /examples instead. I have just moved and renamed the file as 
/doc/flow_classes/#camera-help.pd because [#camera] doesn't have a help file 
and because it doesn't belong in /examples, which is for demoing what's 
possible with GridFlow (generally large patches), whereas /doc/flow_classes is 
for help files (which are small patches except for the larger number of 
comments in them).

> Once you have it running, you have to select the "colorspace YUV420P" and
> "transfer read" options and select the YUV -> RGB conversion.

Yes. That's because I don't know an automatic way to detect the transfer type 
(how to download images from the driver), and each driver may skip 
implementation of one of the two ways, because it's not implemented in a global 
way. The rest is because kernel authors *forbid* driver authors from 
implementing any color conversions inside the driver. (!!!)

To anyone dealing with Video4Linux 1: What's a good way of autodetecting a 
suitable colorspace ?

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| Mathieu Bouchard - tél:+1.514.383.3801 - http://artengine.ca/matju
| Freelance Digital Arts Engineer, Montréal QC Canada

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