keep video files in sync

[mic]

Hi,

i have two video cues starting together; the second auto follow the first, no prior post wait are set for both. I notice the second is late of some decimal of second - you see it by the counter running close to the cue, but even the files are kind of video you can notice when they are not precisely in sync.

How could I obtain perfect syncing?

regards

michele

[micpool]

Put in a fire all group and preload?

Mic

[mic]

Hi mic,

thanks for the suggestion.

I tried, with no luck - same behavior. They don't really start together.

ciao

michele

[micpool]

There is no reason they shouldn't play in sync, even if not preloaded

Try creating 2 syphon surfaces and assign 1 video to each surface. View using the audition window.

Do they start together then

If so is the problem one of output or display  latency after QLab?

Mic

[mic]

hi,

let's describe better the situation.

I have 2 video. The second is a cropped part of the first, and has an alpha channel that erase the background.

I start them together, the second above the first.

I should not perceive the above video, if they run together (and they did in qlab 2)

Now, I can as they are not synced I presume.

This video: https://www.youtube.com/watch?v=B1jAxLqpKe0

shows that the two video has the same (I check the first frames in Quicktime).

But you can see that when i run them from QLab, preloaded, they are not in sync.

Both are ProRes4444, the second with alpha channel, both are 25 fps.

any ideas?

thanks

michele

[micpool]

2 ProRes 444 files is quite a hefty data rate particularly at higher resolutions.

Mic

[mic]

Hi,

I converted the back video to PhJpg, keeping the from one to prores4444 to keep alpha. But they are still out of sync.

Now, the back one is 787x575 pixel, 11mb. The front one is 360x370 pixel, 41mb. I have a SSD, doesn't sound impossible rates.

I forgot to mention that both loops are set to infinite but they are ut of sync since the first run. Unlooping doesn't solve.

mic

[mic]

Hi,

I solved, reencoding the file. Now they run in sync. Not sure what really happened though. I can only hipotize that running two files exactly of same size is fine; running two files of different size, like before, presented the issue. 

ciao

michele

[Sam Kusnetz]

Hello All

On top of the other notions discussed, I’d like to add that you can force two Video cues to stay in sync if they have audio tracks and are assigned to the same audio output patch. That causes them to use the clock of that audio device as a sync source, which is what forces the sync.

Best

Sam

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[Sam Kusnetz]

Hello, me again…

I realized I was not clear on one point… if both videos have no audio track, they will also stay in sync (as long they are triggered with a single GO). What I was trying to say is that if *either* video has audio, then they should *both* have audio and both be assigned to the same audio patch.

Sorry for the vagueness of my last post. I need more coffee this morning, apparently!

Sam