INTERACT FORUM

Devices => Video Cards, Monitors, Televisions, and Projectors => Topic started by: Z0001 on May 23, 2018, 04:02:02 am

Title: Why do I need a muscular GPU when a teeny Chromecast gives 4k HDR
Post by: Z0001 on May 23, 2018, 04:02:02 am

Probably a silly question, revealing what I don't understand, but why do I seem to need a punch GPU in a a HTPC for 4k +HDR etc while a little Chromecast ultra seems to do the job? It even has a Plex app?

I don't understand!
Thanks for the schooling
Z

Title: Re: Why do I need a muscular GPU when a teeny Chromecast gives 4k HDR
Post by: RD James on May 23, 2018, 05:25:59 am

A number of reasons really. Anything older than a GTX 950 or so simply lacks the hardware to decode 4K video - which means that it has to be done on the CPU, and that is very intensive.
madVR uses pixel shaders to process video rather than dedicated hardware, which means that processing is far more flexible and can produce much higher quality results, but it also means that it's demanding to run.
If you tune the settings for speed, rather than image quality, it should be able to run on relatively low-end hardware.

Title: Re: Why do I need a muscular GPU when a teeny Chromecast gives 4k HDR
Post by: Z0001 on May 23, 2018, 05:26:29 pm

I see thanks. So a Chromecast a hardware optimised device, that is doing the same job on the video data as our MC HTPCs but in hardware rather than software?

I wondered if the Chromecast was just passing the stream to the TV to decode with it's equipment.

I guess in any case what this means is that if I want to play back a 4k rip of my discs, a software solution is likely to be the most available as the hardware on these little devices might not be set up to do the job?

Title: Re: Why do I need a muscular GPU when a teeny Chromecast gives 4k HDR
Post by: RD James on May 24, 2018, 01:21:02 am

It is doing the "same job" if you consider that to be playing back video at 4K, but a HTPC will be doing a much better job of upscaling content to 4K, and can process 4K video to improve image quality.

Title: Re: Why do I need a muscular GPU when a teeny Chromecast gives 4k HDR
Post by: tij on May 28, 2018, 11:18:03 pm

even if your source is 4K … there is upscaling involved … UHD bluray store video in 4:2:0 … those 2:0 basically indicate dropped out color details that needs to be upscaled/rebuild (chroma upscaling) … TV usually expects to receive at least 4:2:2 (so player has to do 4:2:0 to 4:2:2) then TV can upscale to 4:4:4 for display

With dedicated GPU ... you can upscale to 4:4:4 at very high setting and send it to TV (so TV does not upscale ... just display)

Of course some people argue that chroma upscaling is not so important (kinda like FLAC vs MP3) ... but if perfection is what you are after ... dedicated GPU is way to go