[5.1.1] Video jerky through DeckLink

I hoped that the update would improve the video performance on Mac Pro (SL), it’s much worse though.
A 1080p video (Avid codec and PhotoJPEG) through Decklink is unusable now.
Reverted to N5.1, performance better (usable) again.

i’m surprised by this. i’ve noticed better video performance with the new release. can you post a link to the small bit of the video file?

Me too!

Video is good here now with Intensity pro.
No dropped frames either. Which it sadly is in 5.1.0


Could you tell us which Mac Pro exactly you have?
Here’s some information from the Read Me PDF:

The updated video engine of Nuendo 5.1.1 uses a new
preload mechanism that allows for fluent video playback even
when highly CPU-loading codecs are used. However, the
large amount of data transfer requires state-of-the-art CPU
types. Low transfer rates will turn out as a bottleneck,
causing in jerky video playback and dropped frames. The
CPU’s front side bus should at least provide a data transfer
rate of 1066 QDR. Modern computers utilizing the QuickPath
(QPI) architecture - for example Intel Core I3, i5, i7
processors typically match the requirements and should be

2 x 3GHz Quad-Core Intel Xeon (2007)
Snow Leopard 10.6.6

sorry, I’m not allowed to post a video clip

Sugar - if you cant post a clip, can you make a dummy clip…

Grab any video file off the net. Or I’ll send you one.

Encode to your settings.

Then send it back so a couple others of us with similar macs can test. I have a VERY similar machine to yours here (2008, 2x4 core 2.8 with 16gb ram and an intensity.)



here are two test video files, both 1080p 23.976 fps

PhotoJPEG Codec

Avid DNxHD Codec, 36.14 Mbps

how do these work on your N5.1.1?

i didn’t have the avid codes installed so locked up n5 the first time i imported the video file. after installing they both import and playback fine. they look identical to me (although it’s not exactly ideal footage for a quality comparison).

Photo-Jpeg is jerky here but resolution is way high for my PC. So no surprise here. I would re-encode it.