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jdavidbakr
10-15-2003, 03:04 PM
We are currently demoing a VT3 for use in a live venue, and have been having some problems with video delay. I ran a video signal through a splitter, put one output into a monitor, and put the second output through the VT3 to another monitor, and shot the two monitors with a camera. There was a TWO FRAME delay - 1/15 of a second - between the two monitors. :confused: Now, that seems unacceptable for a live venue, which is certainly something that NewTek is pushing. I am really hoping that there is something set up incorrectly, because in order to use this I have to get rid of this delay! Anyone have any experience working with this?

bbeanan
10-15-2003, 05:10 PM
From what I understand this is normal for most switchers, on the higher end switchers you will get a 1 frame delay. On switchers like the VT3 with and internal TBC you get the two frames because the switcher needs that time to sync the two sources that will be switching.

In a live venue on a large screen the "average" person will never notice a 2 frame delay, even to the trained eye 2 frames is hard to notice...

That is what I have heard at least????

Oh and here is an interesting fact...

The average time it takes for a complete human blink is about 300 to
400 milliseconds or 3/10ths to 4/10ths of a second. Of course this is an
average only and can differ from person to person. Also, there are other
factors that can affect blink speed, like fatigue, medications,
diseases, and injury to the eye area. Most factors decrease or slow the
blink rate.

ted
10-15-2003, 09:31 PM
This is true with any digital Switcher. One to Three frame delay depending on what else you are going through isn't uncommon.
If you go through a projection system it too can add a frame or two delay.
The most widely method to eliminate this is to use an Audio Delay device. This will make everything sync up.

Kurt_Henning
10-15-2003, 10:01 PM
the 2 frame delay is an industry standard.

You can spend 250K on a grass valley switcher and get a 2 frame delay

You can spend 2 grand on an old amiga toaster with TBCs and get a 2-3 frame delay.

I think there was some talk of a one frame delay, but I am skeptical.

2 frames is fine, 4 is a problem.

You should be using composite, yc, or SDI.

DV will give you a larger delay than is acceptable live

This should not stall a sale. Like I said before, 2 frames is what you get for 250 grand. I think the having (2) t3s would be a better bang for their buck.

One of my favorite parts of t3 is switching live. You can really do some great stuff. Just practice at home first.

jdavidbakr
10-16-2003, 07:48 AM
Yeah, the 2 frames from the toaster PLUS 3 frames for the projector is _very_ distracting (that's 1/6 of a second; the lip sync/music beats/etc are VERY noticable, even in the back of the room). We actually just got new projectors but apparently they have a longer delay than the old ones, thus complicating the issue. The thing of it is, we have currently an _industrial_ Panasonic switcher driving our projection screens and the delay is a frame and a half less than it is through the VT3, implying that the Panasonic is introducing a delay of less than one frame. I was hoping there was something that I could disable to make the processing faster inside of the VT3; we are probably going to have to send our projectors back and get different ones. We love what the VT3 can do but right now the delay is way too much... Oh, we are going in Composite for the sources and going out to the projection screens via Y/C.

jdavidbakr
10-16-2003, 08:11 AM
BTW, I'm looking at a spec sheet for the Sony DFS-700 digital switcher ($20,000), it has a composite/S-Video delay of less than 50ns (that's .00000015 frames). Unless I'm misunderstanding what that means.

EanJay
10-17-2003, 12:45 PM
The delay can be used as an effect. Frame-up a performer, and then place that on a screen behind him/her, and include that in the picture - a slight camera motion adds to the effect!

Don't allow the drummer to see the screen, or at least warn him before hand - he will go crazy trying to catch-up to himself.

EanJay

dml
10-18-2003, 08:45 AM
As a reference point, the Play Trinity had a one-frame delay and was used (is still used) very successfully as a live switcher.

Matt Drabick

PIZAZZ
10-18-2003, 03:49 PM
make sure to genlock your cameras if you can. That will reduce the delay at least a frame. Also try to minimize any additional equipment in between the VT system and the Projectors. For example don't use a line doubler or similar piece of equipment.

Genlocking cameras so they are all scanning the same will help the VT system not work as hard. While your at it, you might genlock the VT system also. (remember you need the genlock card to do this)

What are the specs of your VT system also??


I have a Trinity I am trying to sell for my church if your interested in it.

jdavidbakr
10-21-2003, 10:09 AM
We're still demoing it, we're getting a dual Xeon today for this weekend. We actually have a TV truck that is doing the camera switching, and the VT3 is a downstream switcher that we are using for titles and video roll-ins, which is more than enough to keep the VT3 guy busy. Ideally once the Alpha Key out is active, we will have the VT3 patched into the DSK of the switcher.

barahn
10-27-2003, 12:21 AM
jon baker said-----"BTW, I'm looking at a spec sheet for the Sony DFS-700 digital switcher ($20,000), it has a composite/S-Video delay of less than 50ns (that's .00000015 frames)."---------

I agree with Jon Baker. The delay really stinks. Delaying the audio is not the answer. You still have the delayed image behing the subject. Going from under a frame with my Sony broadcast switcher to 4 frames with BOB was a big change. If Newtek is going to sell this for live then it needs to work for live. 4 frames does not work for live. They say 4 is OK or normal but after they come up with a fix for it, then it will be said that 4 frames were too much. I'm very disappointed. I guess I go backwards to analog. What a shame

jdavidbakr
10-27-2003, 07:58 AM
Is it the BOB that adds most of the delay, or is there as much delay if you don't use the BOB? What other options are there if you don't use the BOB (I know the BOB is an option, so how many sources/outputs do you get without it?)

bbeanan
10-27-2003, 08:24 AM
I believe without the BOB you get 1 input and the delay would still be there. The delay is there because of the internal TBC (time base corrector) this allows you to cleanly switch video without the need for genlock and or timing of your various signals.

And just to clear up one point above the delay is 4 frames only if you live switch DV (firewire) sources which even Newtek says is not acceptable. With a BOB switch your delay is 2 frames which again is really not to bad, and if it is that much of a problem I would say set your VT3 system to the side and try to get a $1 million dollar PO signed to go with the best the professional broadcast world has to offer (which you will still get some bit of delay, around 1 frame). Oh but you still need to keep the VT3 as a $1m system still would be missing some items that the VT3 can do better.

I would bet if you took a audience of 100k random people did an IMAG event with a VT3 and 2 cameras. Then at the end told everyone that there was a problem with the system. I would bet that maybe 1 or 2 would say there was a 2 frame delay (actually I think no one would notice). The only way to really notice is to have your talent stand right next to a monitor and test it, seperate the two and you can not notice any delay (in my opinion).

To sum up, the VT3 is a great product at a great price. Really, it like buying a Pinto and getting the performance of a Ferrari, just without the leather(a slight delay) (not to compare a VT3 to a Pinto but more about the $$ side of it).

This is all just my opinion, and you just got me at a one of those time that I feel like wrting a short book.
:D :D

barahn
10-27-2003, 08:25 AM
Yes - I love VT3 and I promote it to EVERYONE.-especially for editing, but I'm not getting 2 frames. BUT - It doesn't take a mill to get a good live switching solution. In our church media department we have the video switching area which we use for the camera switching. A completely different area has our DVD, vhs and computer outputs which go directly to the projectors. All of the outputs go out to the projectors with minimal delay except for the signal coming from the BOB. I thought in the beginning that it could be some of the other components in the line which were causing the delay and that there was NO WAY it could be the BOB which was attributing to most of it. When I took the BOB out of the loop, my signal was back to normal. (1 frame delay) YES, I have another option: go back to my sony broadcast analog switcher.

bbeanan
10-27-2003, 08:31 AM
Also keep in mind your projectors also add around a 1 frame delay, as does a scailer, line doubler...

Basically, any time your signal travels through any device that device by the very nature of phisics will add a delay in, which when added up makes a big delay.

barahn
10-27-2003, 08:47 AM
Just as a note - I hooked up a direct line out of my CCU for the camera and ran it directly to the projectors, which by the way, are 7700 ansi Christie Digitals and the signal was great. Then I ran it through all of the other components-less the BOB- and it was still fine. Add BOB - Delay. I don't know. Thats all I know. I do have a buddy in Fla. who bought a $12,000 component switcher and he doesn't have delay problems but I can't spend that. He's made out of $ - hehe.

bbeanan
10-27-2003, 08:56 AM
exactlly $12,000 or $3,000 for a VT3 (ok $6k for a complete basic VT3 system), and can his $12k system do NLE, CG, DDR, 3D Animation. So I hate to say this but you get what you pay for, for $3k you get the power of $1m with the side effect being a 2 frame delay. Every choice you make comes with side effects.

I can also assure you that you are getting a delay (all be it small) from all of your mentioned hook ups... again simple phiscs (speed of light, signal processing, what type of cable you used, and so on)

bbeanan
10-27-2003, 09:02 AM
Shot in the dark here but take a camera and flim a time code source (from like a Betacam deck or something). Then take that source and feed it into your system.

Next take another camera and film both the time code source and your video screens both in the frame (thay way we can see the actual delay you are getting, hit pause and do the math) post that video here and then maybe Newtek can help you... you never know you could have a bad something???

Paul Lara
10-27-2003, 09:07 AM
Light travels faster than sound, so audio is delayed by about one frame of video every 36 feet from the screen. This means an audience member sitting 70 to 90 feet from the screen would experience perfect sync, even with 3 frames of latency.

barahn
10-27-2003, 04:33 PM
No - all he can do is switch with it. What ever the side effects are of VT3 - Nothing on the market can compare. I really don't understand these people paying $20 - $30 for an editing system these days. And those who pay $150,000 for an Avid Symphony system have to be out of their minds. No-one has ever been able to explain to me what the $143,000 difference is. It can't be the avid name any more. If anyone knows - I like to know.

Jim_C
10-27-2003, 04:38 PM
>>If anyone knows - I like to know.

I have tried to have the same discussion with my Corvette driving neighbor about my Geo Metro.
He didn't get it either.
Some people.
;)

jdavidbakr
10-27-2003, 04:59 PM
Light travels faster than sound, so audio is delayed by about one frame of video every 36 feet from the screen. This means an audience member sitting 70 to 90 feet from the screen would experience perfect sync, even with 3 frames of latency.

Yes, that's all well and good until your projectors also have 3 frames of latency, and unwilling to help because they are using the same arguments that no one will be able to notice 3 frames of latency... now you have 6 frames of latency, which means you now have to be 216 feet away from the screens to be in perfect sync. This is far from acceptable especially when the head honchos are sitting 20 feet away from the screen.

jdavidbakr
10-27-2003, 05:01 PM
What ever the side effects are of VT3 - Nothing on the market can compare.

This I have to agree with, and is why we are going with the VT3 - for the price point, there is nothing like it. However, what we are gaining in price we are losing in hair as we try to solve this signal delay problem.

Paul Lara
10-28-2003, 05:24 AM
don't know if it's worth it for you, but you can shave off one frame of VT latency by adding on the optional $695 Genlock card. That'll bring it down to 2 frames.

barahn
10-28-2003, 05:37 AM
Geo Metro and a corvette - hahahahahahahahaha
They both get you there but one is faster and rides better.
BUT- I need some one to tell me how the other systems are faster and how do they ride better.
You have to understand, I have used 2 different Avid ($30-$40) systems and I don't know where the extra comfort or speed is. Saying you drive an Avid instead of a Toaster is about the only weight I see. I have not used a symphony Avid yet so maybe that's where the difference is. (Geo - hahahaha)

bradl
12-02-2003, 11:45 PM
Originally posted by Kurt_Henning
the 2 frame delay is an industry standard.

You can spend 250K on a grass valley switcher and get a 2 frame delay

You can spend 2 grand on an old amiga toaster with TBCs and get a 2-3 frame delay.

I think there was some talk of a one frame delay, but I am skeptical.

2 frames is fine, 4 is a problem.

You should be using composite, yc, or SDI.

DV will give you a larger delay than is acceptable live

This should not stall a sale. Like I said before, 2 frames is what you get for 250 grand. I think the having (2) t3s would be a better bang for their buck.

One of my favorite parts of t3 is switching live. You can really do some great stuff. Just practice at home first.

Kurt,

2 Frame delay is not at all an industry standard. All current digital production switchers must have 0 frame delay or to be more specific less than about 40 lines. If they didn't, you could not use pre-read and no one would buy it. This is true for current GVG/Thomson, Sony, etc.

Abekas had a really fine digital switcher years ago (A-82, I think), it was back when they were building large production switchers, and it had a 1 frame delay that eventually killed it as no one wanted it. The current Abekas switchers (now sold as Accom 8150, etc.) have a 1F or 34 lines selectable delay.

Using house black as a reference allows for machines and cameras to be connect in time and not need a frame buffer or frame sync to connect to the switcher. Low-end and consumer gear generally does not allow timing in this fashion and therefore requires a frame-sync to be built into the switcher, such as VT3, which actually has 2, one for each input or bus which causes 1 or more frame delay.

Now AFAIK all DVE's will produce a 1 Frame delay (some used to get down to 1 field).

Artvisions
07-16-2004, 11:35 PM
I thought that the toaster also delayed the audio a frame or so, so both video and audio get delayed equaly.

Faraz
07-17-2004, 01:42 PM
Artbeats- That's true but that doesn't work in a live venue because the sounds can't be delayed or the speaker would hear himself etc...

If you're not doing complicated DVE's there might be a way to shave down the delay... I'm not sure if it still works but once upon a time it did. I'll have to check up on it and let you know, but at MOST the delay will come down to a frame...

Artvisions
07-17-2004, 01:59 PM
In my case, I would be sheltered away from the live sports.

In my truck, or in another room with headphones.
This would work, and the product would be in perfect sinc right? Even if I use live effects, etc? I'm new to the new Toaster.

Thanks for any help.

Faraz
07-17-2004, 04:51 PM
Right you don't have to worry about that. Since you are not re-broadcasting the signal back out live.

Artvisions
07-17-2004, 10:44 PM
I guess you mean if sound from the live event feeded back into the control room/truck sound mix? (live sound mixed with moniter sound)

An echo whould exist in that situation, I think.

Fireknight2k
08-12-2004, 09:17 PM
Here is the bottom line. It's a problem maybe newtek will come up with a fix but I doubt it. We all understand it now to bad we didn't before we purchased it.

PIZAZZ
08-12-2004, 09:23 PM
The delay will Never get better than 2 frames. 1 frame to syncronize the signal coming in and 1 frame to sync the signal on the way out. This only will be possible in situations when you have the cameras Genlocked together. (less work for the VT that way)

Most people haven't noticed this before BUT the projectors have had a frame or 2 delay already there. We didn't notice it until the VT added another 2 or 3 frames to the existing delay. Thus making the delay visible to more than the trained eye looking for it.

If it doesn't work for you then spend the same amount of money of a VT on a Panasonic MX70 and get 1/4 of the features. Life is full of trade offs.

alexxi
08-13-2004, 06:47 AM
Found here:
http://www.newtek.com/support/tech/faqs/VT/vt-troubleshooting-index.php

CBaldoni
Super Member

Registered: Jun 2003
Location:
Posts: 799
What's with the delay in my live output?

What's with the delay in my live output?

 We know that this is a serious issue and are going to work on fixing it.
 We have a good idea on how to fix it but do not want to risk making radical changes to the drivers that would effect the entire switcher real-time performance this close to shipping.
 If you genlock the cameras to the Toaster output and adjust them correctly you should be able to get 3 frames latency.

Last edited by CBaldoni on 06-26-2003 at 04:56 PM

-----------------

(valid for PAL)
We just made an Live-production with 5 Ikegami HL55/59 all equipped with TriaxBasestation. Adjusted from professional technicians with external equipment like Textronic Waveform and Vectorscope, offcourse all Cameras and VT3 genlocked to an external broadcast certified Syncgenerator.
We got a delay from approxm. 120ms, this is about 3 frames and this is to much.
If I can drop another frame, I would be more satisfied.

Pizazz:

What is your secret to reach 2 Frames in NTSC-Land??


PIZAZZ wrote:
"Most people haven't noticed this before BUT the projectors have had a frame or 2 delay already there. We didn't notice it until the VT added another 2 or 3 frames to the existing delay. Thus making the delay visible to more than the trained eye looking for it."

Newtek´s Homepage:
".... All inputs are internally time-base corrected and genlocked, making the time and expense of on-site setup easier and more affordable than ever before....
...Only NewTek can offer 8 component input switching at this price, with the flexibility of using up to 24 composite inputs....
SX-8 Switcher Expansion module
... All inputs can use whatever cameras you have at your disposal, and unlike more expensive switchers, does not require multiple cameras to be genlock-able. Find out more... "
___

Yes, I found out more: that using ungenlockable cameras (interestingly dependend which you are using, Canon worst..) you get a delay between 4 to 5 frames on an ordinary Videomonitor.

alexx

sbrandt
08-14-2004, 05:01 PM
Can someone get Dan Hong to chime in on this...

I thought WeThree did a lot of big production stuff VERY successfully.

How do you do it Dan; or do you experience the same thing?

essentricaudio
08-14-2004, 05:35 PM
We use the VT[3] for IMAG support in our sanctuary. While there is several frames of delay, the only time anyone seems to notice it is when they sit with the screen directly behind the speaker - then what they notice is the delay between the speakers arm moving and the movement on the screen - very slight, but once you notice it, it will drive you crazy.

Now of course I noticed and can observe the delay from the back of the room, but I have only recieved 2 comments on this from the congegation - and both of them were just wondering why it did that.

BTW, our room seats 900 on the main floor and 300 in the balcony. we have 2 screens behind the platform. Projectors are Digital Projection DLP.