Lip Sync and Plasma Monitors

[dr sound]

Richard,
While this is "hardly new information", the reason I posted it was for those who did not believe my and "The Chinese (Todd)" original postings well over a year ago. I put this up so that it might have more impact since it is an article from a magazine instead of what a Re-Recording Mixer found out. Not new news, just news. Yes we should know.

[dr sound]

Poster: Richard Fairbanks
Subject: Re: Lip Sync and Plasma Monitors

I have to vent on you all. This is hardly new information.
SNIP
The powers stopped playback to point out a sync problem? Come on! The problem was obvious before that playback ever happened and should have been noticed.

dr sound replies:
Before you go crazy Richard, The way the room works at Sony is this; the plasma is in the back corner of the Stage (Stage 6) and is not on during the dub. It is turned on and the Mix is played back on a small set of TV speakers for client playback at the end of the mix. The main playback is done on a huge projection screen in front of a wall of THX JBL's, so it wouldn't be apparent until the end of the mix. That plasma was installed recently. Hence the lack of awareness.
Picture of stage 7 (a mirror image of 6)

http://www.sonypictures.com/studio/postprod/tvrr.htm

[Richard Fairbanks]

Sorry, dr and Craig, I was not aiming at either of you, quite the contrary, I appreciate your pointing out the audacity of a manufacturer's rep who thinks that 100ms or less can be ignored. Doc, I know you were using the article to stir up some more realistic discussion.

I DO go crazy when basics are ignored. It is a personality flaw. I do not mean to offend any individual, and for that I appologize. I said I am venting on you, not blaming you, unless you are in charge of the facility who makes such a huge mistake.

Installing the plasma and using it for client evaluation, without proper research or a check of performace before hand, is hard to justify. Didn't anybody take a critical view? That Abbey Road can do the same thing is also jaw-dropping. Plasma, LCD, and light valve monitors all have latency (plasma more then the others). This is common knowledge to technical persons in our industry. Sony and Abbey Road should have known better. Frankly, they deserve a little egg on their faces. If my tiny place allowed that sort of sloppiness I do not think I would have repeat clients.

If Sony is using video projection on that big screen then there will be some latency. If it is a good projector it might only be 15 or 20 ms but it is there. A facility must take responsibility for keeping its own systems in sync with each other, no matter where the cause is. To do less might be called a "three monkey approach".

[AG]

< Picture of stage 7 (a mirror image of 6)>>

That pretty much sums it up, thanks Marti. With Sony, it probably happened like this. One day you show up on your stage and see the TV monitor replaced with a Plasma and say cool then go back to mixing. Actually the latency was talked about, but there were so many factors involved, you just do what the client suggests and try to make them happy.
BTW Marti, did Dusty call you? He asked me for your number. I owe both of you guys lunch so maybe one day when we all have some time off.
_Scott

[dr sound]

BTW Marti, did Dusty call you? He asked me for your number. I owe both of you guys lunch so maybe one day when we all have some time off.
_Scott

Scott,
No I haven't heard from Dusty. I'll take you up on the lunch.

[houser]

Hello,

Coming in late to this one...but just a quick note that we have been on Plasma
for years...and the first thing we did was offset the videosource by the appropriate amount.
We happen to use Virtual VTR so that was not a major problem.
Only bummer is if we need to playback on the CRT at the same time..
making us have to explain this issue..that you can't have synch on the
Plasma and the CRT at the same time.. ,-9
We now have some test sessions with audio/visual beeps that get opened whenever something
is changed or serviced...just for safety.
oh and BTW..DVI is even worse for latency...

FWIW
Janne A.

[Richard Fairbanks]

Offsetting an external video playback works well, so does changing the quicktime movie sync offset value. AVXL users do not have any option like that (why not, Digi?). During laybacks to video tape or watching DVDs or anything outside of Pro Tools the system fails, though. The only method that guarantees audio/video sync is to delay the audio monitors to match the video latency. You can do this in Pro Tools, but you have to remember to turn the delays off for laybacks (or to bounce). If you have spent years fine tuning your beautiful analog monitors you will not want another A-D-A delay in your monitor path and you have a problem.

What has worked well here is to use the Tascam DSM7.1's delay trim settings for this purpose. The delays can be globally turned on and off with one click, so when I use the CRT I have delay off and when I use the projector I turn it on. I am covered for any possibility, which allows me to sleep at night.

[georgia]

ok.. I might be really stupid, but why not just 'push' the video positioning in protools forward the appropriate amount to offset the video delay instead of mucking with the audio?


Cheers
georgia
(who uses CRT displays and 3 Gun CRT projectors so has not a clue about this issue as yet not having had to face it...)

[Richard Fairbanks]

why not just 'push' the video positioning in protools forward the appropriate amount to offset the video delay instead of mucking with the audio

Yes, that puts realtime playbacks through Pro Tools in sync. You might get into trouble when you start trying to locate an exact hit point, like a drop or a scene change. Because you slid the movie, the frame you seek will not be parked at its actual position. A timecode burn, when parked, will show a different frame than your Pro Tools counter. I've tried to work that way and did not enjoy it.

[Stuart P.]

Hello,
Yep, delaying the main room's audio is the most sure-fire way I've seen people get around this. The Ranes are good little boxes for the job. Just keep them in your monitor path only, cause' you'll probably forget to bypass the delays for laybacks (at two in the morning who can remember anything, much less to bypass some dark-colored box under the mixers farting area).

If you're using one of Mr. Gilbert's necessary evils, then another way is to use Virtual VTR's DV or sync delay offsets in its preferences. Sometimes this is the ideal way to go. It depends. This way, you can still use machine control/MMC and the video system will still display the proper locate frame

Gotta be careful no matter what you do though, especially if you need multiple viewing systems going at once. The stage audio can be delayed at the monitoring-only side of things, and the rest of the folks can watch CRTs in the machine room and client areas with in-sync audio (as long as they're fed the non-delayed audio and not the stage mix or its fold downs).

You've all already stated this stuff, I guess I'm just exercising my metacarpals by writing this.

Later,
S.