Qlab3 Video Codec Data rates and quality comparisons

[micpool]

16:9 25fps Video Files Data Rates MB/s
	ProRes444	ProRes422(HQ)	ProRes422	ProRes422(LT)	ProRes422(proxy)	h264 50% qual
1080p	36	24	15	10	4.5	5
720p	18	12	7.5	5	2	2.5
480p	12	8	5	3.5	1.5	1

Above is a table of data rates for the 5 flavours of ProRes Codecs and h264 rendered in After Effects at 50% Quality.

In experiments I have found a rough rule of thumb is to determine what your Qlab system can handle by seeing how many simultaneous 1080p individual videos you can run comfortably, and calculate the total data rate. You can then use the table to estimate how many files in codecs of greater or lesser data rates you might be able to run

e.g on my MacBook Pro system I can run 4 ProRes 422 (LT) 1080p videos totally reliably. So in theory I could run 8 720p videos in (LT)  or 16 720p videos in proxy codec.

A low spec Mac Mini might only manage a quarter of this performance. A Mac Pro with SSDs should  manage considerablymore

I have attached a very large picture file. This is a  table similar to the one above but instead of numerical data it has  screen grabs taken from a portion of 1920x1080 surface in Qlab. In each case the video is scaled to the full surface size. 

The attached download is at actual pixel size. Its easier to use if you open 2 copies of it in Preview. then you can compare the quality of  any  2 different codecs side by side. An interesting place to start is to compare the four videos with data rates 4.5/5 MB/s. I've always liked files with data rates around 4MB/s in Qlab. That's always seemed to be an optimum sort of rate for general purposes even going back to running DV files in Macromedia director ten years ago. I have had to use jpeg compression to get the file under 10MB which is the google group file limit. If you want a higher quality version let me know and I'll send it to you.

This is a small version purely to show the grid  layout of the big one You need to use the full resolution download to actually make worthwhile comparisons:

I hope you find this useful. It's certainly made things a lot clearer to me.

Mic

[micpool]

I can't get the small image to appear in line in my post I've attached it here instead

[micpool]

[Gualicho]

Muy bueno, sos un mounstruo!!!
Very helpfull, you rule!!!

Thanks...