[AG-TECH] Issues with a new AG 3.1 installation.

[Douglas Kosovic]

Hi Miguel,

Now that I think about it, if you are capturing four 720x576 PAL video 
streams, you're most likely hitting PCI bus saturation issues. The four 
Pinnacle PCTV PCI capture cards would be sharing the limited PCI bus 
bandwidth (as most motherboards don't have independent PCI buses for 
each of the PCI slots). PCI has a peak bandwidth of 127MB/s and 
depending on the fps capture rate, would leave just 8 MB/s leeway.

One workaround might be to not select 'large' on all the video streams, 
or use a PCI-e x1 Bt878 quad-input capture card which are starting to 
get cheaper.

I might even add some code to vic which stops the vic capture, then 
sleeps for a period of time and restarts the capture if the VIDIOC_DQBUF 
I/O error happens more than a 100 times in a row.


Cheers,
Doug

Douglas Kosovic wrote:
> Hi Miguel,
> 
> You might like to try setting the VideoProducers to V4L instead of V4L2 
> and see if you get similar issues.
> 
> Sorry I'm not sure what the cause of the issue is, but will try to 
> reproduce next week.
> 
> 
> Doug
> 
> -----Original Message-----
> From: owner-ag-tech at mcs.anl.gov on behalf of Miguel Sáez
> Sent: Fri 5/16/2008 9:37 PM
> To: AG-TECH list
> Subject: [AG-TECH] Issues with a new AG 3.1 installation.
> 
> Hello,
> 
> I'm currently testing a new AcessGrid 3.1 installation with 2 computers;
> - The first one is a Linux Fedora Core 9 (kernel: 2.6.25.3-18.fc9.i686)
> with 4 video capturers connected to 4 cameras. This computer is working
> as H264 video producer with a Service Manager launched.
> The 4 video capturers are Pinnacle PCTV Rave (chipset: Conexant FUSION
> 878A).
> - The last computer is under Windows XP SP3 working as a H264 video
> consumer.
> 
> I start the AGServiceManager on the linux computer and then on the
> windows computer i launch my venue client and i configure there the
> consumer and producer video services. When i connect to my venue
> everything works fine; vic gets launched i can see all the videos
> perfectly and smooth but after a few time, (about 20-30min) one of the
> cameras freezes completly (it's random the camera that freezes) and i
> start getting the same error all the time in the console where i
> launched the ServiceManager:
> 
> ioctl VIDIOC_DQBUF: Input/output error
> 
> Also if i check the dmesg output i get errors there, for all the other
> devices (bttv1, bttv2 and bttv3):
> 
> bttv0: SCERR @ 369d9000,bits: HSYNC OFLOW FBUS SCERR*
> bttv0: timeout: drop=41 irq=114623/114624, risc=369d9000, bits: HSYNC
> OFLOW FBUS:
> 
> I have checked if the video capturer cards where being loaded with the
> right module and driver and seems they are.
> 
> At this point i don't what else i should check or do, so if anyone got a
> clue about what's wrong any kind of help would be appreciated.
> 
> Greetings,
> 
>