720/24PN & Avid DNxHD 90

[jasper]

I'm shooting a short film on the Panasonic HVX200 in 2 weeks. I want to shoot in their native 24PN to save space. However I don't want to sacrifice quality. If you shoot in 720/59.94 and bring it into avid, you can transcode to DNxHD220. If you shoot 720/24PN and bring it into the avid you can only transcode to DNxHD 90. Has anyone tested this before? Is the quality about the same or am I better off going with 720/59.94 and sacrificing the space issue? Thanks for any and all input.
jeff

 

[cbrougham]

I believe that the numbers attached to the DNxHD codecs aren't compression measurements or representations; instead, they denote bitrate in megabits per second (Mbps). So, here's the math:

DVCPROHD 720/60p: 100Mbps
DVCPROHD 720/24pN: 40Mbps
DNxHD220 = 220Mbps
DNxHD90 = 90Mbps

100Mbps : 40Mbps = 2.5:1
60fps : 24fps = 2.5:1
220Mbps : 90Mbps = 2.444:1 (or, approx. 2.5:1)

The compression is the same; it's just the total packaged bitrate that's different. Anyway, I think that's how it works, and would explain the reason you only see the DNxHD90 option in the 24pN project.