Help with 7:1 content output.

[thomatron]

Hi there,
i need some help with overcoming a latency problem with a led video wall using 2 outputs from a server std.
The System i am using is a Coolux server standard controlled by a Manager Pro. The led wall is 2540 x 360 pixel surface controlled by 2 processors (this is due to the limitation of the led processor only being able to handle a 1920x1080 max res.)
My client has had custom content made for the screen at the correct resolution in a .png image sequence which i have then converted to .mxl at 20k bitrate
i have then scaled the project on each of the outputs to fill the screen.
The issue i have it that there is some noticeable delay between the left and right half of the screen particularly during the faster motion graphics where flashes occur 1 -2 frames late on the right hand screen. I should point out that it wasn't my idea to have 7:1 content!! we are only running 1 layer of content at a time when the delay happens.
i have tried changing processors, removing every piece of equipment from the system that could introduce lag etc and the problem persists.
i have also tried increasing the memory size, turned on fluidmotion and re encoded at a lower bitrate.
if necessary i can do the scaling externally but the added latency will not be good for the occasional imag layer we have in the project.
I have a digital matrox triple head that could be used but not sure of the process with drivers etc or if this will fix the problem. i can also try splitting the content but not sure of the workflow once i have done the split.
can you offer any advice on a solution or where i'm going wrong and if i can use the triple head with a server pro?
thanks for your Help
Thom Anderson

[malkuth23]

Hmmmm. Without being there in person it is hard to say this 100% confidence.
But I am 99.9% sure this has nothing to do with the Server. Playing 1 layer out of a dual output server should never have a sync problem. As far as I know, it would be impossible for it to have a sync problem because it is a single video that is coming off a single video card. I can tell you that I have tested 4 outputs from a Server feeding directly to LED walls and to 4K projectors with no sync problems.
But I have seen this exact same problem with some LED processors. They do not time perfectly and have problems syncing with one another. I am willing to bet good money the problem is in the processors. I know this is not great news as there is no easy solution, but I don't know what else to tell you.
Have you changed out the processors for a different brand or just to a backup from the same manufacturer? Can you share the manufacturer of the LED processor?
I would not split the content. There is no reason to and it only adds work.

TL:DR - it is your processors.

[thomatron]

Thanks for your response, i have to say all the evidence does point to this as no matter what i did i couldn't get the problem to change. i was just hoping it was something i was doing wrong, not something that is hard to fix...
The processors we have are a novastar brand (not amazing i know), the good news is i believe they make a larger res processor that can handle the image size natively which may help.
Not that it will therefore help in this situation but with regards to a triple head is there a process of installing drivers on a server to make it work or should it just work out of the box?
Thanks again
Thom Anderson

[JustynR]

What I've done with Barco stuff... and DBstar processors is to check the option "Lock to Input" for the sync settings.
Obviously it may be called something different...
And I'm not sure what that will get you because you're running off of 2 processors...

What I may suggest doing is putting all of the LEDs on 1 processor so it is perfectly in sync and aligning it one on top and one on the bottom...
Then, use the Matrix Patcher to move that one to the side... OR share layers on between 2 layers in PB if you don't have any movement or interactivity.

If neither of these is an option, just make sure that the LED processors have exactly the same number of tiles per processor... We've noticed that if one works harder... it will cause more delay also.


good luck!

[malkuth23]

just make sure that the LED processors have exactly the same number of tiles per processor... We've noticed that if one works harder... it will cause more delay also.

That makes a lot of sense. Good suggestion.