Nanoflash 4.2.2 Long-GOP vs Nanoflash 4.2.2 I-Frame at DVinfo.net

David Issko · August 21st, 2009, 03:52 PM

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

August 21st, 2009, 03:52 PM	#1
David Issko Major Player Join Date: Jul 2008 Location: Melbourne, Australia Posts: 393	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. __________________ David Issko Edit 1 Video Productions

August 21st, 2009, 04:25 PM	#2
Mike Schell Convergent Design Join Date: Apr 2005 Location: Colorado Springs, CO Posts: 869	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- __________________ Mike Schell Convergent Design

August 21st, 2009, 09:08 PM	#5
David Issko Major Player Join Date: Jul 2008 Location: Melbourne, Australia Posts: 393	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. __________________ David Issko Edit 1 Video Productions

August 21st, 2009, 05:46 PM	#3
Steve Phillipps Inner Circle Join Date: Apr 2006 Location: Wales Posts: 2,130	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

August 21st, 2009, 06:20 PM	#4
Rafael Amador Major Player Join Date: Jun 2009 Location: Vientiane (Lao PDR) Posts: 349	I agree with Steve. The capability of conforming to a different time-base without transcoding is great. Rafael

August 22nd, 2009, 07:11 AM	#6
Steve Phillipps Inner Circle Join Date: Apr 2006 Location: Wales Posts: 2,130	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