[AG-TECH] VenueClient crashes

Christoph Willing c.willing at uq.edu.au
Wed Oct 22 15:26:35 CDT 2008

On 23/10/2008, at 1:05 AM, muhammad akl wrote:

> Christoph,
> Now everything seems to work fine with Nvidia chip card and it's  
> driver on ubuntu hardy , also upgraded my connection to 1Gbps. but  
> the problem now is that other participants are not able to see my  
> video while i could see their vidoes (they are using normal video  
> streaming not DV or HDV) , So I would like to ask
> Must be other participants in the node have the same hardware , I  
> mean must they have nvidia cards , 1Gbps connection, and aghdvic  
> application installed ?

The short answer is yes, in particular the aghdvic package.

The longer answers:

- a 1Gb is not strictly needed, although highly desirable. A single  
DV/HDV stream generates 25-30Mb/s, so multiple streams will quickly  
saturate a 100Mb/s network.

- some other video cards may work but unless they implement certain  
acceleration features, some signal decoding is attempted in software,  
causing a very high load on the machine itself.

- the same hardware (camera) is not necessary to just receive DH/HDV  
streams from remote sites; only a suitable video card and the aghdvic  

> or i can summarize that the question : what are the requirements  
> should be existed to transmit DV or HDV between mustlicast group in  
> the same node ?
> I hope your answer contains the  required hardwares and softwares  
> as well

As you have suggested above, each site would have DV/HDV camera  
available as well as nVidia graphics card (driven by nVidia's binary  
"nvidia" driver, not xorg's standard "nv" driver"), sitting on a  
reasonably high bandwidth network.

The DV/HDV services provided by the aghdvic package use a different  
multicast address to the standard H261 video which is why the other  
participants could not see your stream. The reason for this is to  
protect sites without high bandwidth capability from being swamped by  
multiple DV/HDV streams. It is expected that only sites that are  
capable of handling the high bandwidth involved will choose to run  
the DV/HDV services.

If sites are unable to run the aghdvic package for some reason  
(including that its currently only available for Linux systems), you  
could still send an additional H261 stream from your DV/HDV camera.  
Most of the DV/HDV cameras I've seen have multiple outputs, including  
composite video which you could feed into a normal composite capture  
card. Then you would run an ordinary VideoService (or  
VideoProducerService) as well as the SimpleHDVideoService. This is  
how we routinely run our UQVislab node - three cameras of normal H261  
video via VideoProducerServices, the main camera also being sent as  
DV via a SimpleHDVideoService.


> On Sun, Oct 19, 2008 at 9:53 PM, Christoph Willing  
> <c.willing at uq.edu.au> wrote:
> On 19/10/2008, at 11:14 PM, muhammad akl wrote:
> Hi Christoph ,
> Thanks alot for your relpy , about the root login I was just  
> testing AG on personal computer not in a production environment ,  
> but sure you are completely right .
> the second problem now I'm facing is caputring video from my  
> digital camera , now I'm using debian lenny instead of ubuntu and  
> all things are fine and could get the video from my sony camera but  
> the picture is exteremely strange here is a screenshot :
> http://muhammad.akl.googlepages.com/acessgrid.jpg
> Muhammad,
> That looks like you don't have an nVidia graphics card, or it is an  
> nVidia card running with the "nv" driver rather than the "nvidia"  
> driver.
> Like most other distros, lenny ships with the nv driver as the  
> default for nVidia cards. However the advanced features in the  
> nvidia driver are needed. I haven't looked recently but I don't  
> think there is a package for lenny yet which supplies the binary  
> nvidia driver module. This means you'll have to download the driver  
> from the Nvidia web site (http://www.nvidia.com/object/unix.html)  
> and install it manually yourself.
> FYI, Ubuntu has the nvidia-glx package available which supplies the  
> binary nvidia driver.
> And for the SimpleHDvidoeservice , it didn't work for me the  
> service that worked here DVideoservice
> This is probably because the SimpleHDVideoService defaults to HDV  
> when your camera is set to DV format. In this case, you need to set  
> the service to DV format in the service's configuration panel (then  
> disable and re-enable the service). Don't forget to store the  
> configuration too.
> my camera model is :
> Sony DCR-TRV285E
> p.s : will the new kernel stack that supports firewire be better  
> the current one ?
> I believe other distros trying the new stack have had some problems  
> so far.
> chris
> Christoph Willing                        +617 3365 8350
> QCIF Access Grid Manager
> University of Queensland

Christoph Willing                        +617 3365 8350
QCIF Access Grid Manager
University of Queensland

More information about the ag-tech mailing list