storage math

[dukduk]

Ok, this may seem silly, but somebody help me with this math for storage when shooting 4K:

4K ~= 4096x2214 = 9068554 pixels / frame
10 bits / sample * 3 (r,g,b) * above = 272056320 bits / frame = 33210 KB/frame
* 24 fps ~= 778 MB/s ~= 45.6 GB/minute

So, uncompressed, your 320GB red drive stores about 6.5 minutes

I read in some other post that Red was saying ~2 hours per drive in 4K. So are they using a 18:1 compression that I'm unaware of did I screw up my math?

Thanks for explaining to me...

 

[Andrew M.]

First, we have 12 bits not 10 per pixel. Also no RGB here each RAW pixel is just 12 bits
RAW is not RGB.

Second 1K = 1024 bits and 1MBits = 1024X1024 bits (MBytes = MBits/8)
4K = 4096 X ???? depends from screen ratio/aspect
Then multiply by frame rate 24, 30
Now, you probably want to get 4.5K as a RAW (get exact pixel count for 4.5K, it is somewhere here on this forum)

Now it is how it comes from RAW high speed port.
From the REDRAW codec you get 11 to 13 times less data.

 

[Emery Wells]

I read in some other post that Red was saying ~2 hours per drive in 4K. So are they using a 18:1 compression that I'm unaware of did I screw up my math?

Thanks for explaining to me...

Welcome to REDCODE RAW.

 

[Chris Kenny]

Ok, this may seem silly, but somebody help me with this math for storage when shooting 4K:

4K ~= 4096x2214 = 9068554 pixels / frame
10 bits / sample * 3 (r,g,b) * above = 272056320 bits / frame = 33210 KB/frame
* 24 fps ~= 778 MB/s ~= 45.6 GB/minute

So, uncompressed, your 320GB red drive stores about 6.5 minutes

I read in some other post that Red was saying ~2 hours per drive in 4K. So are they using a 18:1 compression that I'm unaware of did I screw up my math?

Thanks for explaining to me...

It's actually 4096x2304, at 12-bit. But it's not RGB, it's RAW data from a Bayer sensor. Only one channel.

So, it's 4096x2304 * 12 bits/pixel = 13.5 MB per frame, or 324 MB/s.

When recording on-board, this image then gets fed through a wavelet compression algorithm, which squeezes it down to around 27.5 MB/s. About 12:1 compression. (But larger images compress better, and wavelet algorithms don't introduce the same kind of horrible artifacts as DCT compression algorithms, so you shouldn't read too much into the fact that this image is more compressed than DV footage.)

 

[Bachman]

12:1, But it's lossless right?

 

[Craig Schober]

lossless

lossless

12:1, But it's lossless right?

visually yes (to most at least) but not generationally or mathematically.