[GEM-dev] dimen problem with 2 pix_video object

[cyrille henry]

just to conclude with this monologue : 
in fact, i had 2 problem in the same time : 
-there is a bug somewhere (in the driver) that make the video to crash when 2 webcam IN THE SAME USB BUS are used in the same time.
if the webcams are not pluged on the same usb bus, then it's ok.

-the other problem is still a bit mysterious, but it appear when 2 [pix_video] try to access the /dev/video0 device. This is the default behaviour of pix_video. This is why compiling V4L2 support solve this problem.
for now, i just change the link /dev/video0 -> /dev/video_0 so gem can't find the video0.
selecting the correct device later is then working.
i don't really know, butthis is maybe also a driver problem.


cyrille




cyrille henry a écrit :
> hello,
> i find somthing interesting : i compile Gem with flag : --with-v4l2
> and now i don't have anymore problem with v4l
> V4L2 work also, but there are some bug. i'll digg them when i'll have 
> more time.
> 
> 
> so, there is probably a bug somewhere in pix_video, but compiling with 
> v4l2 solve it...
> 
> cyrille
> 
> 
> 
> 
> cyrille henry a écrit :
>> hello,
>> i've got 2 philips webcam SPC900. i plan to use them in an installation.
>>
>> there as been some discution on this list about this webcam in september.
>>
>> i've got a diferent problem that is introduced only using 2 of this 
>> camera in the same time.
>>
>>
>> i made a simple test patch that just have 2 pix_video, and a message 
>> "device 1" and "device 2" (device 0 is my internal webcam)
>>
>>
>>
>> the problem is :
>> send device 1 to the 1st pix_video -> ok
>> send dimen 640x480 to the 1st pix_video -> ok
>> send device 2 to the 2nd pix_video -> ok
>> send dimen 640x480 o the 2nd pix_video -> the video stay black but 
>> every other thing work.
>> sending a device 0, or removing the 2nd pix_video make everything to 
>> stop and i have to manually kill pd
>>
>>
>> changing order give the about the same result : send device 1 to the 
>> 1st pix_video -> ok
>> send device 2 to the 2nd pix_video -> ok
>> send dimen 640x480 o the 2nd pix_video -> the video stay black but 
>> every other thing work.
>> send dimen 640x480 to the 1st pix_video -> ok
>>
>>
>> send device 2 to the 2nd pix_video -> ok
>> send device 1 to the 1st pix_video -> ok
>> send dimen 640x480 o the 2nd pix_video -> the video stay black but 
>> every other thing work.
>> send dimen 640x480 to the 1st pix_video -> ok
>>
>>
>> send device 2 to the 2nd pix_video -> ok
>> send dimen 640x480 o the 2nd pix_video -> ok
>> send device 1 to the 1st pix_video -> the video stay black but every 
>> other thing work.
>>
>>
>> what i call : 1st pix_video, is the 1st to be rendered.
>>
>>
>>
>> i tied to store the image size in the memory of the cam with the 
>> setpwc tools, in order to test Iohannes patch to restore setting.
>> but i've got 2 problems :     -setpwc does not work for saving and 
>> restoring data in the non volatil ram (Roman : it was working for you 
>> : do you hae an ida why it's not working here?)
>>     -just like Roman, i've got black frames when using iohannes patch. 
>> (i don't know if it's important but this black frame disapear when i 
>> change size of the video)
>>
>>
>> so, i can't have 2 of this webcam at a good quality on the same time, 
>> and it's a major problem for my installation.
>>
>>
>> i also try to use them in 2 diferents pd on the same time, and i've 
>> got the same problem. if i use my internal webcam + an external one, 
>> then everything work.
>>
>>
>> so, i suspect a driver problem, and don't know if a solution could be 
>> find.
>> what do you think?
>>
>>
>> if it's a driver problem, then i'll certainly have to buy another webcam.
>> does anyone have a recommandation to make, for a linux compatible webcam?
>>
>> thanks
>> Cyrille
>>
>>
>>
>>
>>
>>
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>>
> 
>