Audio Sync Adjustments

Audio Sync Adjustments

on Jul 17, 2008 at 9:19:30 am

Hey folks,

So we got a lovely new LCD panel for our clients to look at, the only problem is that audio seems to be slightly out of sync with our grade monitor.

Both screens are connected to a Kona LH - the grade monitor via SDI and the LCD by component.

I trust the sync to the grade, it seems spot on. I guess the LCD is doing some kind of video processing that delays the signal by a frame or two.

I'm wondering if there is a way of temporarily adjusting the AJA audio to sync it to the LCD? For normal work I look at the SDI connection, but sometimes it's more important for the LCD to be in sync.

Thoughts?

-Simmie
3 MacPros - Kona 3 & Kona LH
2 G5s - Kona LH
2 G4s - Cinewave
xbox360, Wii, PSP, PS2
http://www.speak.co.uk

Re: Audio Sync Adjustments

on Jul 17, 2008 at 12:01:55 pm

I have the same problem with the ioHD and 1 frame delay on the LCD. Because LCD's are always progressive they need to buffer the fields before they can display the whole frame - hence the 1 frame delay. This is at least my explanation :-)
According to Aja the next driver will have audio adjustments possibilities for different outputs.
How it'll work I don't know. We'll have to wait for the new drivers.
Not sure if there will be new drivers for the LH as well. Guess best to drop Aja a line (or call :-)

Hope this helps.

Carsten

Re: Audio Sync Adjustments

by Bob Zelin

on Jul 17, 2008 at 12:27:03 pm

in the mean time (just for the hell of it), go to System Settings>playback (4th tab in), and tell me where the frame offset is - it defaults to "4", but should be "0" for most systems. Yours may vary.

Everyone is anxious for the "audio slew" feature in the "yet to be released" new control panel.

Bob Zelin

Re: Audio Sync Adjustments

on Jul 17, 2008 at 12:30:35 pm

[Bob Zelin] "in the mean time (just for the hell of it), go to System Settings>playback (4th tab in), and tell me where the frame offset is - it defaults to "4", but should be "0" for most systems. Yours may vary."

Hi Bob, thanks for the suggestion - that was the first thing I tried. Didn't seem to make any difference to the Kona outputs, it only seemed to change the offset between the FCP window and the screen...

-Simmie
3 MacPros - Kona 3 & Kona LH
2 G5s - Kona LH
2 G4s - Cinewave
xbox360, Wii, PSP, PS2
http://www.speak.co.uk

Re: Audio Sync Adjustments

on Jul 17, 2008 at 12:48:13 pm

ups you beat me to it :-)

Re: Audio Sync Adjustments

on Jul 17, 2008 at 12:47:36 pm

Unfortunately that doesn't change anything, as the playback offset only influences the desktop (computer) display to the external display (which ever that maybe). There will always be a 1 frame difference between a CRT and a LCD.

Re: Audio Sync Adjustments

on Jul 17, 2008 at 12:28:12 pm

Thanks Carsten, guess I'm going to have to look at a HDMI converter and see if that helps...

-Simmie
3 MacPros - Kona 3 & Kona LH
2 G5s - Kona LH
2 G4s - Cinewave
xbox360, Wii, PSP, PS2
http://www.speak.co.uk

Re: Audio Sync Adjustments

on Jul 17, 2008 at 12:50:53 pm

The only way, short of the new drivers, that I figured is a audio delay you can buy for home cinema setups. They have adjustable delays.
Though if you delay the audio for the LCD, your CRT will be a frame to early :-(
I didn't go there, or at least not yet, before I see the new drivers.

Re: Audio Sync Adjustments

by Jeremy Garchow

on Jul 17, 2008 at 11:55:52 pm

Just wait for the new drivers. But it will then unsync your grade monitor.

Re: Audio Sync Adjustments

on Jul 18, 2008 at 8:48:45 am

[Jeremy Garchow] "But it will then unsync your grade monitor."

That's OK, it'll just be for when I need to use the big screen. A preset that I can switch will be just what I need. Guess it's the waiting game!

-Simmie
3 MacPros - Kona 3 & Kona LH
2 G5s - Kona LH
2 G4s - Cinewave
xbox360, Wii, PSP, PS2
http://www.speak.co.uk

Re: Audio Sync Adjustments

by Jeremy Garchow

on Jul 19, 2008 at 8:15:51 pm

[Stuart Simpson] "A preset that I can switch will be just what I need. "

It won't be a preset so much as a little slider that will adjust the audio sync. It's very cool and easy and hopefully coming soon.

Jeremy

Re: Audio Sync Adjustments

on Jul 21, 2008 at 9:59:41 am

[Jeremy Garchow] "It won't be a preset so much as a little slider that will adjust the audio sync. It's very cool and easy and hopefully coming soon."

I've just heard from engineering that this feature is coming to the LH/Kona3 but the new drivers will only support audio skew for the IO HD at the moment. Bummer for us as we'll have to wait longer, I guess for now I'm just going to have to manually shift audio sync for our client viewings...

-Simmie
3 MacPros - Kona 3 & Kona LH
2 G5s - Kona LH
2 G4s - Cinewave
xbox360, Wii, PSP, PS2
http://www.speak.co.uk