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latency displaying 720p video input with blackmagic board?

eskatonia
Novice

May 9, 2007, 2:30 AM

Post #1 of 7 (2276 views)
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latency displaying 720p video input with blackmagic board?	Can't Post

Hi there,

I just tested isadora on a mac pro tower with a blackmagic decklink studio hd board. We are trying to do effects on a 720p (1280x720 60hz) incoming video stream. I know this is very high resolution but this is a quad core intel mac....

The incoming video signal has approximately a 2 secs latency delay which would make it unsuitable for what we want to achieve. Blackmagic's own deck control application and final cut pro are able to display video at this reolution with no latency.

is there anything I could try to improve the video input latency?

Roger
Inside-Us-All

Mark Coniglio
TroikaTronix / Moderator

May 9, 2007, 7:07 AM

Post #2 of 7 (2272 views)
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Re: [eskatonia] latency displaying 720p video input with blackmagic board? [In reply to]	Can't Post

A few questions first:

1) What effects specifically are you trying to use?

2) Are you using the "External Output" feature to output? Or does the DeckLink appear as a stage?

3) What are the frame rates like? Is it 30fps but delayed?

Best,
Mark

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Mark Coniglio / TroikaTronix
Creator of Isadora

eskatonia
Novice

May 9, 2007, 8:27 AM

Post #3 of 7 (2265 views)
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Re: [Mark Coniglio] latency displaying 720p video input with blackmagic board? [In reply to]	Can't Post

no effects yet, just putting the video up on two stages filling display 2 and display 3 (from the nvidia graphics cards not the blackmagics output)

what we wanted to do is split the 720p hd stream over three outputs with a custom mask effect and a curve applied but we haven't got to that stage yet, as I can't use isadora for this project unless we can get the latency down to much lower than this.

frame rates are good, easily 30 fps but with the delay

the blackmagics output does show up as a stage as well, but we're not going to use that functionality, we need component hd 720p input only

(This post was edited by eskatonia on May 9, 2007, 8:29 AM)

trukske
Novice

Feb 23, 2008, 11:24 AM

Post #4 of 7 (1492 views)
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Re: [eskatonia] latency displaying 720p video input with blackmagic board? [In reply to]	Can't Post

i have the same problem. It seems to me that Isadora is causing the latency, and not my capture card/computer. There is also a big difference between the image on the 'video input preview' (apple k) and the 'stage' (apple g) from isadora. In the first, there is less latency. I capture with an intensity card on a macpro 8-core. This should do the job...

In general I'm suffering a performance problem. I'm able to play high res videos on a second screen without a problem with quicktime but with isadora there is a frame rate problem: the image is not always continuously and 'jumps over' some frames when there is a lot of movement (information) in the video. Maybe it is the 2.9 version?

anybody suggestions to solve this?

william
User

Feb 25, 2008, 9:34 PM

Post #5 of 7 (1445 views)
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Re: [eskatonia] latency displaying 720p video input with blackmagic board? [In reply to]	Can't Post

2 Second latency... what are you outputting to?

Are you switching from DVI to HDMI by any chance?

Try switching your compression to NONE and lowering your input video quality. That might get your latency down at least a few frames.

Tell us more specifics about your setup.

trukske
Novice

Apr 1, 2008, 9:45 AM

Post #6 of 7 (1084 views)
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Re: [william] latency displaying 720p video input with blackmagic board? [In reply to]	Can't Post

I bought a EVI-D70 pan/tilt camera. It transmits video using the Photo Jpeg compression. With this camera, I have almost no latency. It works better than any camera I tried.

I use the cheapest decklink card for capturing: Intensity pro.

For compression type in the video input settings I choose 'Uncompressed 8 BIT', this works better than 'None' compression. The video output resolution and the camera input resolution are the same as the native resolution of the camera 752x576.

Hard disc recorder cams are the worst, DV is ok but still too much latency, mini spy cams with small resolution are also ok.

Ief.

lakota651
New User

Apr 28, 2008, 11:31 PM

Post #7 of 7 (918 views)
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Re: [eskatonia] latency displaying 720p video input with blackmagic board? [In reply to]	Can't Post

Hello ~

I am wondering how your video signal is (or was) being handled by your computer. I am making the assumption that you maintained your native resolution, but what type of signal is it (component, HD-SDI, etc.)? Also, what is the resolution that Isadora is handling the live feed at, are you in RGB or Y'UV mode, and what resolution of your stages?

Thanks~

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