Is there a codec that has zero/near zero color data loss with small file sizes?

Report · Jan 02, 2023

Hi all,

Our short film is on the stage of color grading now and the director has taken the onus of coloring the film himself. The problem is...

The director is running low on storage due to ongoing projects. I told him that, I'll export a pro res 4444 file for him to color grade on.

The problem is, a Pro Res 4444 export at 1280 by 700p comes out to 19GB. and I promised, a file no bigger than 5GB to color grade on, since anything over that is an absolute nightmare to transfer.

Due to the INSANE file sizes, I wonder if there is any codec that I can export my project in which has ZERO (or near zero) color data loss with not very insane file Sizes at 720p? Do you think pro res 422 would cut the mustard here?

More details about the project:

(If it helps!)

Camera: Sony A7smk3

Footage: XAVC-I 4k 240MBPS Bit Rate

Resolution: 3840x2160p@23.976fps

Shot in S-LOG 3

Project Length ~26 minutes

Export Resolution for the film once it is final

4096x2160

Thank You!

Report · Jan 02, 2023

Nope, you cannot have both. It's either a small file size with image loss or (visual) lossless codec.

Tell your director to get a bigger drive.

Report · Jan 02, 2023

Compression works by the nature of human visual perception. We are more sensitive to luminance data than chorminance data (color). Plus ... dit-depth is a major part also.

So ...

444 is keeping the full content in all three channels, R, G, B.
422 drops a quarter of the color data.
420 drops half the color data.

Then bit-depth pops in.

8 bit stores 256 levels of data per pixel.
10 bit stores 1024 levels of data per pixel.
12 bit stores 4096 levels of data per pixel.

The practical result is:

for full ability to push tonal/color data around, you need a 444 chroma file of at least 10 bits.
for decent ability to push tonal/color data around, you can get by with a 422 file of at least 10 bits.
for SDR/Rec.709 final deliverables, where no further changes will be made per pixel ... you can use either 420 10 bit or 8 bit.
for HDR final deliverables, you should use 420 10 bit (for covering dynamic range).

So your director has a quandary. More space ain't expensive these days, they should probably just add more drive space. That would be the easiest solution.

Or ... they could color with t-codes to a smaller file size, then after finishing, simply offline the low-res t-codes and reconnect to the full res files. A bit more hassle but that's been done in the biz for years.

Neil

Report · Jan 02, 2023

Thank You for the reply. Welp, its time to pay him a visit it seems