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-   -   Nanoflash 4.2.2 Long-GOP vs Nanoflash 4.2.2 I-Frame (https://www.dvinfo.net/forum/convergent-design-odyssey/305706-nanoflash-4-2-2-long-gop-vs-nanoflash-4-2-2-i-frame.html)

David Issko August 21st, 2009 03:52 PM

Nanoflash 4.2.2 Long-GOP vs Nanoflash 4.2.2 I-Frame
 
Ok, so at 100mbps, the Long-GOP is classified as 'Master Quality'. So how much lees quality is 100mbps in I-Frame? Is it really perceivable or is it apparent under shooting/ost conditions such as (only as an example) chroma keying or colour grading?

What about under straight forward, cuts/dissolves only editing?

My Media 100 Suite is an I-Frame edit system and I just want to know what the best recording setting in the nanoflash I should use. Obviously I will know when my unit arrives (being shipped on 24th Aug) after I do tests, but if anyone has any idea, that would be greatly appreciated.

Cheers.

Mike Schell August 21st, 2009 04:25 PM

Hi David-
Long-GOP is typically 2X to 3X more efficient than I-Frame only. So 100 Mbps Long-GOP = 200 to 300 Mbps I-Frame only. There is a significant improvement with Long-GOP recording.

Best-

Steve Phillipps August 21st, 2009 05:46 PM

2 things to consider with I Frame - with higher bit rates it'll take more storage space, and it'll also need faster cards. If you can get away with 100 mb/s GOP it sounds as if it'd be crazy not to. Only reason I would use 220 mb/s I Frame would be for shooting 60P for conforming into slomo, as Cinema Tools will only do I Frames.
Steve

Rafael Amador August 21st, 2009 06:20 PM

I agree with Steve.
The capability of conforming to a different time-base without transcoding is great.
Rafael

David Issko August 21st, 2009 09:08 PM

This is what I understood matters to be. So, how o I change the Long-GOP recordings to I-Frame for editing in Media 100 without picture quality loss? I use Apple ProRez 422 HQ for all of my EX3 footage editing. Obviously it works for EX footage so I suppose I petty much do the same thing when importing the nanoflash recordings.

Steve Phillipps August 22nd, 2009 07:11 AM

You can transcode into Uncompressed - but even with that there was quality loss from my original PDW700 files 0 and the output files were huge! The edit suite in the production house would play them realtime but I don't think many home set-ups would.
When I was contemplating hooking up a Nano to my PDW700 I decided I'd use fast cards in 1 slot to shoot 220 mb/s I frame for the 720/60P stuff, then switch to the other slot with slower cards to do 100 mb/s Long GOP for 25P. In the end I got a Varicam 2700, but looking at Ofer Levy's latest stuff on opsreys I'm not sure I made the best choice!
Steve


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