[FFmpeg-devel] [PATCH] avcodec/nvenc: High bit depth encoding for HEVC

[Timo Rothenpieler]

On 18/04/2024 14:29, Roman Arzumanyan wrote:
> Hi Diego,
> Asking for my own education.
> 
> As far as you've explained, the 8 > 10 bit conversion happens within the 
> driver, that's understandable.
> But how does it influence the output? Does it perform some sort of 
> proprietary SDR > HDR conversion under the hood that maps the ranges? 
> What's gonna be the user observable difference between these 2 scenarios?
> 1) 8 bit input > HEVC 8 bit profile > 8 bit HEVC output
> 2) 8 bit input > 10 bit up conversion > HEVC 10 bit profile > 10 bit 
> HEVC output
> 
> Better visual quality? Smaller compressed file size?
> In other words, what's the purpose of this feature except enabling new 
> Video Codec SDK capability?

Video Codecs tend to be more efficient with 10 bit, even if it's just 8 
bit content that's been up-converted to 10 bit.
I.e. yes, it'll (Or can, at least. Not sure if it's a given.) produce 
smaller/higher quality content for the same input.

As for the exact reason, I can't explain, but it's a well known concept.