| Delaying Audio to Sync With Video [message #106518] |
Mon, 13 February 2006 19:14  |
 Josh Wozniak
Messages: 40
Registered: October 2005 |
Should Get Out More |
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I have been dealing with this for way too long....my audio is very noticably ahead of video when playing back DVD's and such. I am atleast 10 frames behind since I am running through a switcher/scaler, distribution equipment, and a projector. Does anyone know of a cheaper solution to route just the video sound through other than using the delay on a protea or driverack? I have a protea but unfortunately its already full.
Thanks to everyone...I have been following the site for quite awhile and have learned so much!!
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| Re: Delaying Audio to Sync With Video [message #106527 is a reply to message #106518 ] |
Mon, 13 February 2006 19:58  |
Eric Snodgrass
Messages: 1809
Registered: October 2004
Location: Los Angeles, CA |
Has No Life |
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No, not unless you get a cheap stand-alone delay unit.
Eric Snodgrass
No, really, I do this for a living.
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| Re: Delaying Audio to Sync With Video [message #106591 is a reply to message #106518 ] |
Mon, 13 February 2006 23:55 |
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Michael 'Bink' Knowles
Messages: 4057
Registered: April 2004
Location: Oakland, CA |
Has No Life |
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| Quote: |
...Does anyone know of a cheaper solution to route just the video sound through other than using the delay on a protea or driverack?
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The cheapest external delay I've seen in use for this purpose was a single (mono) Behringer Shark processing what was originally a really interesting stereo mix. Would I recommend the Shark? No, it's a little to hissy, IMO.
The real answer is Rane's purpose-built AVA 22d.
-Bink
Edit: Forgive me for being blunt but there's no way you are looking at ten frames worth of delay. Usually it's more like two to six, sometimes seven.
[Updated on: Mon, 13 February 2006 23:57]
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| Re: Delaying Audio to Sync With Video [message #106796 is a reply to message #106518 ] |
Wed, 15 February 2006 01:09 |
Thomas Bolvig
Messages: 3
Registered: February 2006
Location: Denmark |
Newbie |
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Hey,
Yeah I suppose a delay-unit has to be "in the package" when dealing with audio from a "live" video feed.
I've personally made it a habbit to require a delay-unit as soon as I hear the key words; Projector, DVD playback, VTR and so on.
Also, in television productions you may encounter that a video signal is being passed through a frame-store device.
This device, as the name states, stores a couple of frames to gain the posibility to sync the signal to the gen-lock from the video-mixer.
This causes further delay to the video-signal but not the audio 
It's a good thing to ask the video-folks if there's a frame-store in use, and if so, how many frames it stores. - scince I think that it's much easier to calculate the delay, than to do it by ear, which in in-door live situations is almost impossible due to the early reflections within the venue.
[Updated on: Wed, 15 February 2006 01:17]
/Thomas
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| Re: Delaying Audio to Sync With Video [message #107029 is a reply to message #106857 ] |
Wed, 15 February 2006 20:59 |
Eric Snodgrass
Messages: 1809
Registered: October 2004
Location: Los Angeles, CA |
Has No Life |
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| Mac Kerr wrote on Wed, 15 February 2006 08:54 |
| Thomas Bolvig wrote on Wed, 15 February 2006 02:09 |
I think that it's much easier to calculate the delay, than to do it by ear, which in in-door live situations is almost impossible due to the early reflections within the venue.
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The problem in a live venue is not the early reflections, it is that the sync is different at every seat in the house. If you want to be within 1 frame of perfect sync, you have a distance window of around 60-65 feet (plus or minus 1 frame). If the audience depth is greater than that, it is not possible to get them all in sync, and the sync will be different in the front than the rear. Sitting at the rear of the house setting the delay so it looks good to you is not the ideal situation.
Mac
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Mac has brought up a quandry that has come up at our venue when we do film premieres or corporates that might have multiple screens. The decision usually made is to delay it to sync in the center of the house, which ends up being around 60-70 feet. It's the compromise that works best.
Eric Snodgrass
No, really, I do this for a living.
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| Re: Delaying Audio to Sync With Video [message #107042 is a reply to message #107029 ] |
Wed, 15 February 2006 21:44 |
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Mac Kerr
Messages: 7027
Registered: April 2004
Location: Westchester County, NY |
Has No Life |
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| Eric Snodgrass wrote on Wed, 15 February 2006 21:59 |
Mac has brought up a quandry that has come up at our venue when we do film premieres or corporates that might have multiple screens. The decision usually made is to delay it to sync in the center of the house, which ends up being around 60-70 feet. It's the compromise that works best.
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I try not to ask anyone, because the producer will almost always want the sync perfect up front where they and the big execs are. I try to make those seats no more than a couple of frames early, depending on the room. Sometimes the room is 250' deep, which means only about 30% of the audience is going to have good sync, and they will be nearer the front. I don't think many people notice one way or the other, i mean how's the sync on your HD channels?  I guess nobody's complaining about the lousy sync on HD.
And those repeater screen...gotta love that idea. If my main arrays impinge on the main screen by an inch I have to rehang them, but if the repeater screen block the entire stage view, who cares?
Mac
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| Re: Delaying Audio to Sync With Video [message #107046 is a reply to message #107042 ] |
Wed, 15 February 2006 22:06 |
Eric Snodgrass
Messages: 1809
Registered: October 2004
Location: Los Angeles, CA |
Has No Life |
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| Mac Kerr wrote on Wed, 15 February 2006 19:44 |
I guess nobody's complaining about the lousy sync on HD.
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The sync on my digital cable sucks. It's always sucked. It's more noticable when I rent an OnDemand movie.
| Mac Kerr wrote on Wed, 15 February 2006 19:44 |
And those repeater screen...gotta love that idea. If my main arrays impinge on the main screen by an inch I have to rehang them, but if the repeater screen block the entire stage view, who cares?
Mac
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Yep. Audio is the poor stepchild in most of these gigs.
Eric Snodgrass
No, really, I do this for a living.
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| Re: Delaying Audio to Sync With Video [message #107388 is a reply to message #107317 ] |
Fri, 17 February 2006 10:17 |
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Mac Kerr
Messages: 7027
Registered: April 2004
Location: Westchester County, NY |
Has No Life |
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| Matt Sears wrote on Fri, 17 February 2006 01:01 |
If you are doing primarly reinforcement and just need to delay playback audio for video - I have a neat trick. Assign all your video playback channels to a subgroup and insert the subgroup to your delay. Only 1 stereo delay needed ....
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This is how it is usually done on an analog console. On many of the digital consoles being used today, if you use the internal delay on the groups, it does not go to the matrix. On a PM1D the mix bus delay does go to the matrix, but on PM5D, DM2000, and DM1000, it does not. In those cases you need to use the input channel delay, or insert an FX device and use it as a delay. When using an analog console, and group inserts for delay, you need to be sure that your record feed is off a matrix, not an aux send, because the aux will not have the delay, and all but about 2 frames of delay in the projector, is actually in the switcher, which also goes to tape.
Mac
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