Originally Posted by ilmazzo
Navi gpus have it, turing and supa dupa turing not, right?
DisplayPort 1.4a with Display Stream Compression (DSC) 1.2
Turing GPUs include an all-new display engine designed for the new wave of displays, supporting higher resolutions, faster refresh rates, and HDR. Turing supports DisplayPort 1.4a allowing 8K resolution at 60 Hz and includes VESA’s Display Stream Compression (DSC) 1.2 technology, providing higher compression that is visually lossless. Table 2 shows the DisplayPort support in the Turing GPUs.
Turing GPUs can drive two 8K displays at 60 Hz with one cable for each display. 8K resolution can also be sent over USB-C (see USB-C and VirtualLink section below for more details).
Turing’s new display engine supports HDR processing natively in the display pipeline. Tone mapping has also been added to the HDR pipeline. Tone mapping is a technique used to approximate the look of high dynamic range images on standard dynamic range displays. Turing supports the tone mapping formula defined by the ITU-R Recommendation BT.2100 standard to avoid color shift on different HDR displays.
As far as I know Turing has the full DP1.4a.
Wiki: DSC is a "visually lossless" encoding technique with up to a 3:1 compression ratio. Using DSC with HBR3 transmission rates, DisplayPort 1.4 can support 8K UHD (7680 × 4320) at 60 Hz with 30 bit/px RGB color and HDR, or 4K UHD (3840 × 2160) at 120 Hz with 30 bit/px RGB color and HDR. 4K at 60 Hz with 30 bit/px RGB color and HDR can be achieved without the need for DSC. On displays which do not support DSC, the maximum limits are unchanged from DisplayPort 1.3 (4K 120 Hz, 5K 60 Hz, 8K 30 Hz).
Compression (Optional) - - - DSC 1.2
Looks like DSC was optional again and as such most monitors don't have it yet.
DSC is an open standard that was developed in liaison with the MIPI Alliance for general purpose display interface compression. It is currently included for optional use in VESA’s Embedded DisplayPort (eDP) Standard v1.4, HDMI and MIPI’s DSI Specification v1.2, and is open for use in other display interface standards as well. VESA anticipates on-going liaison activity other parties interested in the DSC Standard as upcoming improvements or revisions arise.
DisplayPort 1.4a supports 8K video at 60Hz and 24-bit color using a low 2:1 compression ratio or 30-bit color using a low 2.5:1 compression ratio, which will provide visually lossless image quality (indistinguishable from the original image), unlike the use of chroma subsampling.
How does VESA’s DSC Standard compare to other image compression standards?
Compared to other image compression standards such as JPEG or AVC, etc., DSC achieves visually lossless compression quality at a low compression ratio by using a much simpler codec (coder/decoder) circuit. The typical compression ratio of DSC range from 1:1 to about 3:1 which offers significant benefit in interface data rate reduction. DSC is designed specifically to compress any content type at low compression with excellent results. The simple decoder (typically less than 100k gates) takes very little chip area, which minimizes implementation cost and device power use, and adds no more than one raster scan line (less than 8 usec in a 4K @ 60Hz system) to the display’s throughput latency, an unnoticeable delay for interactive applications.
So it should be OK latency wise.
Originally Posted by Asmodian
DSC is not lossless
, it is way better than chroma subsampling and is reported to be "visually lossless" but it is not mathematically lossless.
Latency is a very interesting point, I have never seen any information about DSC and latency. I expect it is pretty fast but does anyone know anything?
From the link above discussing improved image quality when compressing YCbCr 4:2:0 less than RGB:
If you get superior image quality with a reduced compression ratio then that means you get worse image quality with the higher compression ratios required for RGB input, and I would always be using RGB.
I think you are correct and it is not lossless as we know it aka 1:1 lossless, mathematically lossless. Still, they could have done that if they wanted to or maybe they already do so next step was lossy compression. GPUs nowadays also use crap ton of compression to increase memory bandwidth, so there are ways to get this kind of stuff done.
Still better than the stupid chroma subsampling.
Originally Posted by Zam15
Need DisplayPort 2.0 ASAP, they've been dragging their feet compared to HDMI.. Hopefully it releases soon and manufactures start implementing it by the next generation in 2020....
From CES 2019:
"the new DisplayPort 2.0 spec, which VESA reports will be released during the first half of this year"
Same date is on wiki.