Video latency calculation

Hi there,

I don’t know if my Blackmagic or Nuendo are lagging the sync or how much it is. To my eyes, everything is ok, but I’m not sure.

Is there any way to measure it to adjust the video latency parameter?

Thanks!

AFAIK, this is the only realible, correct measuring tool.
http://www.pharoahaudio.com/syncheckproducthomepage.html


Fredo

Thanks Fredo!

It’s really expensive for a one use tool :frowning:

What sort of screen are you playing back the video on?

DG

it looks that way but i thoroughly recommend getting one. it’s the only way that you can be 100% sure that you are in sync. if you change any part of your system (computer/pci card/even nuendo version) it’s possible that the sync can shift.

i like the reassurance of having it.

A TV monitor thru HDMI

I made a small movie that has 24 frames of black and then one frame of white. On every white frame there is a pop around 500 hz.
I play the movie on Nuendo and video it from the screen and record it with onboard mic with handycam or similar. Then I import the new handycammed video to nuendo and check from the timeline how much white frame and pop are drifted. Then fix it in Nuendo and handycam the original video once more.
Then import new handycammed video to nuendo and check if aligned properly. If not, another fix and then another round again.
Takes time but works. Have checked 2 systems like this. And verified first with syncheck to see if this works. It works.

Bye / Tumppi

I’ve tried this with the iPhone camera but it was VERY inconsistent.

I think that Steinberg should produce an app or an option to help to solve this problem.

Thanks for the input :slight_smile:

There are many reasons why an iPhone or any other recording device doesn’t cut the deal.
Simply because you assume that there is perfect sync between audio & video in these devices.
It’s not.
As explained on the Syncheck webpage.

Fredo


Fredo

Thats an excellent idea. Have to try it!!

Of course you have to use some camera you know and works well. I guess mobile phones cameras arent there yet…
Testing with a clapper is good idea. I used a mini dv cam by phillips.

But still. Have synched two workstations and it works.

Bye / Tumppi

That’s a good idea.
But there are a couple of reasons why the latency should be measured upon playback.

Fredo

Before opening this thread I tried recording with an iPhone and it failed. Now, I’ve tried with my wife’s Canon 60D and it worked pretty well. The measurements were the same in every click. I use the 0 ms / 0 frame sync with audio mp4 file at http://www.editorsean.com/blog/49-audiovideosynctest

I hope it helps.

You might be right.
But I see that Syncheck is firing 5 pulses per 2 seconds at different intervals, so there must be a reason for that.
When measuring we always see a tad of variation, which hoovers around perfect sync.
This makes me think that “only having a few claps in a few seconds” won’t be accurate enough.
Also, read the article on the Syncheck page why popular audio/video devices are not up to the task.

That being said. I am convinced that you can get reasonable and usable results using another method.

(Edit)
Just a thought. If you film @25 frames per second. How can you see variations below 1 frame?

Fredo