Kramer VP-747

[tch999]

Hi

 

I've read a few articles on forums including here where people have mentioned the brief processing delay on the Kramer VP-747 when hooking up a video camera for a live camera to screen.

 

We've hired in a Kramer VP-747 this week to use with a live camera but I'm now becoming a bit fearful that there's going to be a noticeable delay on the screens. Is there anyway of reducing this by cutting out some of the processing that the unit does to the signal? I've previously used cameras with the VP-727 and not noticed much of a delay, but perhaps this was down to the camera we used then.

 

I'm a bit of a novice when it comes to tweaking the settings inside the Kramer but I'm sure there's some ability to adjust the processing that it undertakes on certain signals... perhaps I'm wrong however!

 

Any help would be appreciated :)

[Nick Mawer]

Please call the Kramer office on 01296 330011 and we will see what we can do to help you.

Kind RegardsNick

[Nick Mawer]

FW version 1.6 reduces the latency on the CV inputs to under 100ms

[sleepytom]

100ms is 2.5 frames - quite a lot of delay compared to real vision mixers.

 

Make sure you run the Kramer at the native resolution of your projectors or you'll get further delay from the projector scaling.

 

@Nick - is there a similar FW upgrade for the 727?

[AHYoung]

100ms is 2.5 frames - quite a lot of delay compared to real vision mixers.

 

Make sure you run the Kramer at the native resolution of your projectors or you'll get further delay from the projector scaling.

 

@Nick - is there a similar FW upgrade for the 727?

 

 

2.5 frames in the real world will be ok, however remember that every single item has a delay including the camera, at best id expect at least 6 frames lens to lens, Its an inevitable fact of life, but generally the low speed of sound compensates as by the back of the hall its all caught up again.... Having loked into the inherent processing delayes in different units, you can get as low as a single from by running vga at 50/ 60hz as oposed to 3 frames on the video and y/c inputs. My advice is use the minimum amount of processing and set everything as tom says to the native resolution, and go in on vga, then you will be as good as you can get.

[sleepytom]

Delay on the VGA side is less important as it will only be playback which is going in on VGA , it's simple to offset or delay the audio to match the video. Camera delay is the real issue.

 

Which is why broadcast vision mixers use genlock, by bypassing all the scaling and frame synchronisation you can get lens to lens delay down to less than one frame.

 

Weirdly the bigger the venue the less important this issue is, as for every 13 or so meters you are from the PA the sound will be delayed by one frame just from travel through the air. Annoyingly this means that as soon as you have a budget for a proper synchronous video system with genlocked cameras and almost zero delay most of the audiance are so far away that you actually want a few frames of video delay.

 

Remember that even in real life there is no such thing as actual lipsync so I would not lose too much sleep worrying about this! Having said that though video which is behind the audio does look very wrong, so it is worth delaying / offsetting the audio on VTs where possible.

[Nick Mawer]

100ms is 2.5 frames - quite a lot of delay compared to real vision mixers.

 

Make sure you run the Kramer at the native resolution of your projectors or you'll get further delay from the projector scaling.

 

@Nick - is there a similar FW upgrade for the 727?

 

Hi Sleepytom, the answer is no, there was less delay in the VP-727 to start with. It uses a different chipset.