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Available compression ratios in Scarlet 2/3"

Yuval Shrem

Yuval Shrem

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responding to this table:

1293435891.jpg


Which of the compression ratios are applicable for Scarlet 2/3"?
(I assume obviously that only the 3k and 2k resolutions are relevant, but wondering about data-rates and how they correlate to the compression ratios listed.

Thanks!

Yuval Shrem
Fable Entertainment
 
No official answer but Jim said the best average choice is 5:1, I suppose Scarlet will start from 5:1 to 12:1, letting the better bit rates for her big sisters (a.k.a Epics).

Anyway... Just suppositions...
 
Last edited:
Originally Posted by Pietro Impagliazzo
Any penalty for shooting 12:1?

What is affected? Bit-depth? Is gradeability reduced? Any info thrown away or compromised?
Click to expand...

Graeme, I summon thee...

Obviously SOMETHING is thrown away. I know that REDCODE uses wavelet compression, which is the same mathematical scheme used for JPEG 2000 compression (but I assume the algorithm is much better). As I understand it, the image is transformed from a series of numbers representing pixel color values to a series of numbers representing coefficients of a wavelet series, which is a mathematical representation of a localized wave packet. Then some of these coefficients are discarded, hopefully in the way that least affects the quality of the image. I think you might lose some small details in areas of fairly similar color.

I think one of the advantages of wavelet, as opposed to DCT compression is that you don't get as much artifacting, so even at higher compression you don't lose much in the way of gradeability. If you look at comparisons of high-compression JPEG and JPEG 2000 images, the JPEG 2000's are softer, but don't have as much artifacting.
 
David Quinn Carder said:
Anxious to get an answer on this as well. Would also like to see an clip or frame at different compression ratios.
Click to expand...

I am definitely looking forward to someone putting the different ratios through a variety of tests - affect on textures like skin, affect on high detail scenes, affect on moire/aliasing, affect on color representation and high frequency color representation...

What excites me the most, I think is the quality of even 12:1 versus what I've been shooting...
 
the compression rates and bitrates are tied together, if im not mistaken... that's kind of the purpose.
 
paulherrin said:
the compression rates and bitrates are tied together, if im not mistaken... that's kind of the purpose.
Click to expand...

Sorry, I meant, compared to the Epic. RC 3:1 might be the top ratio for both Epic and Scarlet. However, in bitrate terms, it will be <100 MB/s for Scarlet, >200 MB/s for Epic.

The 3K 2:1 figures might just be a good indication to run-times for the Scarlet.
 
oh, i guess i get what you were saying. and yes, i think you're correct.

i'm more interested in what the cf cards can handle... i would think at least 3k @ 7:1 @ 120fps... my guess
 
Yuval Shrem said:
responding to this table:

1293435891.jpg


Which of the compression ratios are applicable for Scarlet 2/3"?
(I assume obviously that only the 3k and 2k resolutions are relevant, but wondering about data-rates and how they correlate to the compression ratios listed.

Thanks!

Yuval Shrem
Fable Entertainment
Click to expand...

No 5K 2/3 fixed scarlet ;)

Thanks for posting this anyway, I got less information (a lot less information from Rd support when I asked them earlier in the week).
 
3k (3072x1620) frame at 12 bit capture is roughly 7.5 MB per frame uncompressed.
At 16 bit capture it is roughly 10MB per frame.
Multiply that by the frame rate and divide by the compression rate to get your data rate.
Epic has a 16 bit capture option, don't know whether Scarlet will too, but it would be nice if that is included in the HDRx upgrade. Really set the camera apart from the typical 8 or 10 bit video camera.
Scarlet won't likely offer less than 5:1 compression I think.
 
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