Hacker News Reader

Comment by magicalist | Hacker News Reader

Does anyone know of any popular camera image formats (ie not raw) that are actually using more than 8 bits per color?

The blog post mentions "8 bits per color channel is not enough", but as far as I can tell everyone using Display P3 for consumer-grade photos (including the iPhone) is still using 8 bits per color, just over the wider gamut.

It seems weird that this hasn't become a thing with the big marketing push behind HDR10 and others for TV. You might think "backwards compatibility", but Apple was fine making the HEIF break and converting when sharing with incompatible devices.

View on HN

It's not entirely about bit depth. Think about 1 bit of a given colour light, it can turn on or off, but the bit depth doesn't tell us anything about the colour of the light it is turning on or off.

Encoding in a larger volume colour space may require additional bit depth to prevent posterization, but that's somewhat tangential. The larger issue is the number of vendors and operating systems that can't get it right. Windows is horrific, for example, with Android being at least as bad, as given by the accounts in the comments here.

> It's not entirely about bit depth

Are you trying to post the same thing in every top-level thread to get your comment seen? This has nothing to do with what I was asking, which was pretty much "everything about gamut and display aside, what's the deal with bit depth?". Hopefully you can see how your response is a distraction.

Nobody to my knowledge is using more than 8 bits per color for taking photos. Certainly nobody using JPG (which includes wide-gamut JPEGs from DSLRs), and at least right now not even HEIF on iOS is anything but 8 bits. I'm guessing because it hasn't caused much color-banding for the typical use case (photos) anyways.

Sony ARW is 14 bits on the A7 line. Canon 5D Mark IV RAW is 14 bit and so is the Nikon counterpart. Even the cheap Blackmagic Pocket Cinema Camera shoots 12 bit RAW.

Why is this important? Most of these cameras images end up on the web. VP9, HEVC and HEIC all support HDR10 so with the right processing this should come through.

JPEG is actually ~12 bits deep, it's just that all the decoders decode it to 8 bit YCbCr, and on top of that cause extra loss by 8-bit YCbCr->RGB conversion. It's possible to compile libjpeg with a 16-bit color pipeline, but it's a hassle, so nobody does that.

Reply on news.ycombinator.com