Does RX580 use AMD's UVD to improve 4K H.264 playback on cMP?

Discussion in 'Mac Pro' started by fhturner, May 17, 2018.

  1. fhturner macrumors 6502

    fhturner

    Joined:
    Nov 7, 2007
    Location:
    Birmingham, AL & Atlanta, GA
    #1
    Hey Everyone—

    I've done a lot of reading about hardware acceleration of encoding and decoding here...chasing joema2 (well, his posts anyway) all over this forum and learning a lot. Since AMD's Unified Video Decoding appears to be in use w/ the Vega 56 and Vega 64 for H.264 playback in the iMac Pro (whose Xeons lack Quick Sync), and since the UVD 6 in the Polaris GPUs can handle at least 4K60 H.264, I'm wondering if anybody knows whether putting an RX580 in a Mac Pro tower will accelerate 4K H.264 playback.

    I have a 12-core 3.46GHz Mac Pro w/ 32GB RAM and a couple of Radeon HD5770s. It is a beast even now, but as you know, w/o Quick Sync, those old Xeons struggle with 4K H.264. I'd like to have better responsiveness in Final Cut Pro X in the timeline when viewing/scrubbing my Lumix G85 (100Mbps) and Phantom 4 (60Mbps) 4K footage.

    There has been plenty of discussion on BruceX benchmarking of rendering, which is helpful, but I'd specifically like to know whether simple decoding/playback is helped by an RX580 as well. The faster rendering of effects is great, but the most important and basic thing to me is responsiveness of the interface and smoothness of playback when doing simple viewing and cutting.

    Can anyone w/ an RX580 comment or do some testing in FCPX to see if the decoding is offloaded from the CPUs? I would imagine QuickTime Player X playback would work similarly, with both programs showing far less CPU usage in Activity Monitor.

    If UVD is in use for RX580s, a follow-up question would be, is it utilized on other Polaris-based GPUs like RX570s or 480s or 470s too? Would any of these others be a better option or value proposition than the 580?

    Oh, joema2, anything to add? :D

    Thanks,
    Fred
     
  2. h9826790 macrumors G4

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #2
    NO, won't help, all GPU video engines are disabled on the cMP in macOS.

    If you want smooth 4K video editing, use ProRes but not H264.
     
  3. fhturner thread starter macrumors 6502

    fhturner

    Joined:
    Nov 7, 2007
    Location:
    Birmingham, AL & Atlanta, GA
    #3
    Okay, thanks. Yeah, I knew and have tried optimizing (or proxy), but was just trying to figure out if there was a way around that so that I didn't have to do it for every 4K project from my MacBook Pro 2015 that I might want to work on on the Mac Pro as well.

    Can you elaborate or shed any light on why it is "disabled"? That makes me wonder...what about eGPU setups w/ the Apple-Developer-supplied RX580? Still no UVD on that either? I guess anything you'd *officially* connect that to would already have Quick Sync... But if you have the hardware available and the system recognizes it, why would "all GPU video engines" be disabled? Is the system looking specifically for Vega GPU w/ an iMacPro1,1 (or whatever) Model ID before enabling?

    Thx,
    Fred
     
  4. h9826790 macrumors G4

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #4
    It's Apple thing, they don't allow us to use it.

    The RX580 in Windows on the same cMP will provide all hardware encode / decode as expected.
     
  5. fhturner thread starter macrumors 6502

    fhturner

    Joined:
    Nov 7, 2007
    Location:
    Birmingham, AL & Atlanta, GA
    #5
    But what about the use of UVD on the Vega in iMac Pro that joema2 has noted? I would think that new functionality might carry over to other systems w/ similar conditions (non-QuickSync Xeon CPU + recent AMD card w/ suitable UVD for source file). Unless Apple is looking for a specific Model ID or something...

    Have you learned anything else about this w/ your setup or experimentation? I know you have a 1080 Ti, but do you perceive any help during playback w/ it? I always enjoy your usually detailed discussions of such matters. :D
     
  6. h9826790 macrumors G4

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #6
    I didn't dig deep enough to know the mechanism behind. All I know is just some Hackintosh user able to use hardware acceleration with some Hackintosh setting that is not available on a real Mac Pro. And that's a RX580.

    Therefore, for Polaris and Vega, the video engine's software is definitely included in the latest macOS, but Apple just doesn't allow us to use it (same as many other functions).

    Nvidia confirm video engine is not available for macOS user yet, but the said my request is already passed to the development team. Hopefully that will be available later.
     

Share This Page