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-   -   I-Frame vs Long GOP --> xfer to film (https://www.dvinfo.net/forum/convergent-design-odyssey/468040-i-frame-vs-long-gop-xfer-film.html)

Micheal McAlexander November 19th, 2009 11:41 AM

I-Frame vs Long GOP --> xfer to film
 
Hey guys,

I'm gearing up to shoot my first feature next summer and I'm trying to get some info on shooting I-Frame vs Long GOP using the NanoFlash if I plan to eventually, after editing, transfer to film for distribution purposes.

Does anyone have experience with this?

Cheers,

Micheal

Rafael Amador November 20th, 2009 12:26 AM

I've just shot a 10 minutes short at 100Mbps and the picture looks gorgeous.
As have been widely stated (and demonstrated) LG is much more efficient than Intraframe.
In theory Intraframe should be better for highly moving images, but I start to think that LGOPs with the adequate data rate will work as good.
rafael

Dave Chalmers November 20th, 2009 01:45 AM

SFX or greenscreen?
 
Quote:

Originally Posted by Micheal McAlexander (Post 1449654)
Hey guys,

I'm gearing up to shoot my first feature next summer and I'm trying to get some info on shooting I-Frame vs Long GOP using the NanoFlash if I plan to eventually, after editing, transfer to film for distribution purposes.

Does anyone have experience with this?

Cheers,

Micheal

Micheal, are you doing any special effects or greenscreen?
If yes, I-frame is arguably a better bet, as each frame is self-contained, but I haven't actually tested this theory yet.
Grading is the other thing that might be affected.

The best thing would be to do some shooting tests if you can.

I think I read somewhere that 160Mbps long GOP is considered effectively lossless.

Regards

Dave C

Dan Keaton November 20th, 2009 02:27 AM

Dear Michael,

At this moment in time, we feel that the 100 Mbps Long-GOP is the sweet spot.

Our even higher bit-rate Long-GOP are even better. We currently offer 50/100/140/160 Mbps Long-GOP, shortly it will be 50/100/140/180 Mbps.

And we offer 100/140/160/220 Mbps I-Frame Only, with 280 coming soon.

The differences between our high-bit rate Long-GOP and our much high bit-rate I-Frame Only are very minor in terms of image quality. We are splitting hairs.

To be clear, I mean comparisons of our "options" versus our other "options".

If one compares "our" high quality options to another competitor's high quality option, I believe that you will find our footage to be superior, lower noise.


Now, for practical advice:

If you are editing in Final Cut Pro you may choose our Long-GOP or I-Frame Only options.

At this moment in time, for Avid, you may use 50 Mbps Long-GOP or any I-Frame Only option. We are working with Avid to obtain full support for our higher quality Long-GOP options.


Long-GOP is always more efficient than I-Frame Only, our highest bit-rate I-Frame Only options may have an ever so slight edge in image quality; this is "Splitting Hairs".


Film-out with out high-quality options works great.


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