Devices > Video Cards, Monitors, Televisions, and Projectors

PC video delay performance

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loddie:
Hi all,

I'm interested in building PC just for JRiver's video delay feature.  This is to delay the video due to audio latency due to processing time on another computer.  While I'm only using 1080p video now, I'd like to have video delay for 4K in the future, so I'm designing for 4K capability.

What part of a computer will determine the video delay performance?  If I understand correctly, the video frames will be buffered in memory for delay.  So what should I upgrade to allow 4K video delay for up to perhaps 3 seconds (not sure of latency yet)?   Is it RAM, video RAM on the graphics card, a solid state drive, more processors, video card processor speed, or some combination of the preceding?

So far I have been able to get 1080HDMI into JRiver using a Blackmagic Intensity Pro 4K. 

JGR48:
It seems you should be able to buffer several seconds of 4K video in memory rather than on disk or in SSD.
Let's look at the arithmetic:
4K x 2K = 8M pixels per frame, roughly
assume 32 bits of color per pixel to keep to round numbers
then 32 MB/frame * 60 frames/sec = 1.92 GB/sec   so with >=8 GB of RAM and not doing much else in the computer you should be good

Don't ask me how to do the I/O to make the memory work as a delay line.   I would like to know myself.  This is a problem that would be nice to solve.

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