Video Playback Tearing/not in sync with quad server

[IvanYap]

Hi

There seems to be tearing in the video playback during one of my gig.

Am using a quad server std and I believe the settings for fluidframe, video buffers and high performance mode at the server end was already on.

But still, tearing appeared at the 2nd & 3rd output.

The funny thing is, it might happen during that certain playback but when you playback it again, it sync again.

Hope someone can enlighten me on this.

Thanks

[Patrick Verhey]

Hi,

can you provide some more information on your setup please? Are you running 4 individual screens next to each other with one video on top? Maybe you see a drawing issue on the screens?

best regards

Patrick

[IvanYap]

Hi Patrick

It's a 4 projectors blended setup with coolux running at the background, edgeblended.

The canvas size for the video is at 4080 x 705.

I dont understand abt what u mean by drawing?

Thanks

[Daniel Kaminski]

Hi,

are all videos tearing? Can you take a picture of that, so we get an idea what it looks like?

What kind of videofiles are you using? is it 1 file or multiple.

What kind of Displays? And how are the cabled?
A little drawing of the setup will help.

Daniel

[IvanYap]

I cant provide a picture right now but I will set it up in my ofc agn and take a photo.

It's a mov encoded into mxl and the funny thing is, although the videos are having the same specs, only that certain video at that certain moment will tear.

It happened during the part where the visual is moving abit fast from top to bottom and it teared between output 2 & 3.

Coolux is doing a playback for that show. As a background. It's outputs goes into barco encore's vp and then to the projectors.

Thanks

[frozenwaffles]

Hi, what res and refresh rates are you running?
What projectors are you running?
Is the tearing in the middle of a projector? Are you warping?

[Dennis Kuypers]

Hello,

Note: Now that I re-read your post I think that this does not apply to you, but I guess this information may be valuable to others, so I leave it here.

When doing a quad setup (so a 2x2 matrix) then you will experience tearing between the rows when parts of the image are moving horizontally. That is due to the fact that screens start drawing at the top and then go down to the bottom.

To illustrate the issue i have drawn something for you. You can see two frames of a video file. It is being played back on two screens that form a column of two. You can see the first frame on the left side. It contains a red rectangle. In the sample the rectangle moves to the right, so that is what you see on the right side. I colored the rectangle blue in the second frame, so it gets really clear what is happening there. Below the frames you can see the displays refreshing. Going from left to right you see how each individual screen starts drawing the new frame from top to bottom (the progress is denoted by the green arrow). You see that while the screens are refreshing the rectangles to not line up until the drawing is done completely. This is probably what you see (assuming you are infact using a quad setup / 2x2 matrix).

tearing.png

This is not an issue of PB, this problem is caused by the technique used by screens today (drawing from top to bottom). I talked to customers that shifted the video files by one frame (or even by half a frame) and they said that it looks better then. You can try for yourself.

Regards
Dennis

[Dennis Kuypers]

Hello,

The high performance mode will put more load onto the server. So if you think that the server is being under heavy load then turning on high performance mode is counter-productive.

As far as I can recall high performance mode puts more data into the memory so the system can react quicker (but this hurts the engine when much work has to be done anyway)

Regards
Dennis