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Epic -W 7:1 Compression VS Epic Dragon 6k 4:1. Which is technically less "Lossy"?

Corey Benoit

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Epic -W 7:1 Compression VS Epic Dragon 6k 4:1. Which is technically less "Lossy"?

I am getting ready to upgrade and just wondering which is technically less lossy? I know that 4:1 is great compression ratio for keying, noise, and most amount of detail possible. So how does 7:1 compare on the Epic-W?


EDIT: Just found out Epic-W does 8k @ 6:1 with 512gb mini mag. Thats good to know! So how would 8k @ 6:1 compare to 6k @ 4:1?
 
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I would split the difference and shoot at 5:1 for as much as possible. More than one Red user has told me they feel that's the sweet spot for economy and the fewest-possible artifacts.
 
Epic-W only goes down to 7:1.
 
Corey, on Epic-W you can get to 6:1 @ 8K with a 512GB or 1TB SSD. I have tested this.
 
Corey, on Epic-W you can get to 6:1 @ 8K with a 512GB or 1TB SSD. I have tested this.

Thats good to know! So how would 8k @ 6:1 compare to 6k @ 4:1?
 
I think it's as Gavin who did some really nice tests and found that for a constant bitrate more resolution with more compression beats the opposite. It seems like in red's compression scheme resolution outpaces artifacts. I'm sure once you reach a resolution that fully out-resolves your output this trend doesn't continue but in his test 6k was visually better than 4K at the same bitrate.

Reds compression also seemed to affect saturation and hue before value so it's possible there's a goldilocks combination for color critical work, but for green screen resolution is definitely more important.
 
Although I have not yet had time to directly compare compression v. resolution, everything I have read agrees with Anton. If I'm doing the math right (and there's no guarantee that I am), then 6K 4:1 is more or less equivalent to 8K 7:1. (It's actually 8K 7.3:1). Meaning even if you are recording 8K FF @ 7:1, you are technically still as good as 6K 4:1. Of course, your real-world mileage may vary, which is why the ability to go as low as 6:1 with the larger mini-mags is nice.

There are people on RU who have test this extensively and can speak with more experience than I. As Anton mentions, Gavin's compression wedges thread is very useful.

http://www.reduser.net/forum/showthread.php?124071-Compression-Wedges
 
Thats good to know! So how would 8k @ 6:1 compare to 6k @ 4:1?

8K is twice the data of 6K, so 6:1 vs 4:1 compression would be an improvement at 8K if you think about it (203 MB/sec vs 161 MB/sec), especially when you consider how CLEAN Helium 8K is.
 
I would split the difference and shoot at 5:1 for as much as possible. More than one Red user has told me they feel that's the sweet spot for economy and the fewest-possible artifacts.

I always recommend the least compression practically possible and agree of 5:1 as the sweet spot, I've been saying that ever since Epic came out.

Users concerned whether they will notice compression difference between 5:1 and 7:1 on 8K footage can stop worrying.
 
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