Posted: February 17 2004 at 8:22am | IP Logged

Hi,

I have just set up a Niagara Kit (Osprey 560) on a dual Xeon 3.3GHz / 2GB WinXPpro host and am having a number of teething problems. The install appeared to go OK and everything appeared to work, until I attempt to start up the encoders in SCX Explorer.

Basically I'm trying to achieve six streams, three in Helix Producer, and three in Windows Media Encoder. One pair is aimed at dial up users, one pair at DSL users, and one pair at LAN users, so QCIF, CIF and FULL sized images respectively.

I appear to be able to start three encoders of one type or three encoders of the other type without a problem, however I struggle to get past three of one and one of the other stage, before encoders start failing to start up, time out, or just sit there 'spinning'. This sort of activity happens even when the CPU load is as low as 10%.

As an experiment, I tried to see how many Helix encoders I could run simultaneously, and found that one of each available bitrate (eight total) at CIF size, started up and shut down without a problem. CPU load reported a load of 50%.  

Trying to add a single 28kbps Windows Media Encoder to this, proved to be difficult though. I did eventually (by luck more than anything else) manage to add a couple of Windows Media Encoders to this lot, bringing the CPU up to 65%.  

In order to start a third Windows Media Encoder, I started shutting down Helix encoders, but even after removing seven out of the eight, no more Windows Media encoders would start. This is even though  I've have had that combination of three Windows Media Encoders and one Helix encoder runing simultaneously previously. 

From what I can tell so far, there appears to be some issue here with encoder processes 'spinning' when they are being started in a situation where another format encoder is already currently running.

Just wondering if anyone has come across anything like this ?

Dave

Posted: February 18 2004 at 3:50am | IP Logged

Hi, and thanks for posting the reply.

I initially tried starting the larger streams first, however I think I've probably tried just about every possible combination now without noticing much difference to be honest ! If I use only the one encoder, I can start streams up and shut them down successfully in any order. As soon as I bring the other encoder into the equation, that's when the problems start.

I am using version 2.2.2 of the Osprey driver as supplied and reccommended.

Viewcast technical support say to start the encoders with the higher bitrates first, whereas the supplied documentation states to start the higher resolution streams first. With Windows Media Encoder streams it's a bit hard to tell as only the 'friendly name' templates are listed and not the actual video size. (By default, some of these I'm sure are multiple encoded streams too.)  I need to investigate how to alter these templates - apparently I require to do this outside of SCX in Windows Media Encoder first.

I've seen the SimulStream guide and noticed the sections on what combinations are problematic - I don't think that I'm breaking any of the rules there, however once again the Windows Media Encoder templates may well be masking some things in this area. The error messages being reported back are a bit vague - will a stream incompatibility be reported as such or will the encoder just fail to start as I'm experiencing.

Dave

Posted: February 18 2004 at 6:39am | IP Logged

Hi again,

I think I may have found a possible source of the problem.

When working with a Helix Encoder driver in SCX Encoder, the dimensions of a PAL video frame are reported as follows:

QCIF - 192 x 144
CIF - 384 x 288
Full - 720 x 576

however when working in windows media encoder, they appear to be:

QCIF - 176 x 144
CIF - 352 x 288
Full - 704 x 576

which could perhaps result in a scaling problem ?

After altering the Windows encoders to match the dimentions of the Helix encoders I now seem to be able to start Windows and Helix encoders .

An issue I've come across when creating custom Windows Media Encoder profiles, is how are you suppossed to refresh the list of profiles that appear in SCX Encoder Explorer after creating / editing then in Windows Media Profile Editor ? Is restarting the SCX Encoder service the only way ?

Also, how do you verify the colour formats being used with a Windows Media format encoder ? For Helix it lists it in the 'Video Settings' tab and it appears to be locked at YUV12.

Dave

Posted: February 18 2004 at 1:08pm | IP Logged

This has definately fixed the problem - I have been able to start and stop encoders all afternoon, first time, every time.

Perhaps one to be added to an FAQ ?

Dave