HEVC decoding on AMD GPUs broken in 10.15.2

Lab
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1

似乎HEVC在帶有最新WhateverGreen / Shiki的AMD GPU（無iGPUless）的10.15.2中無法正常工作。自從beta以來，這種情況以前從未發生過，並且許多用戶都在報告問題。


https://www.tonymacx86.com/threads/catalina-10-15-2- update-lost-hevc-h265-acceleration.288563 /

Here is my test, i can confirm that there is NO FREEZE or PANIC so far:

  1. add boot-args: shikigva=32 shiki-id=Mac-7BA5B2D9E42DDD94 on top of my iMac19,2 SMBIOS, make sure everything is using AMD GPU. ( i use these boot-args just for testing AMD GPU, so that the iGPU is not used during my test )
  2. use QuickTime to record my 4k screen, i did a 4m47s recording
  3. use QuickTime to save as 1080p in HEVC format, it takes less than 4mins to finish the encoding.
  4. during recording and encoding, the CPU usage is around 3%, it is pretty amazing.
  5. play back the recoded 4k video and encoded 1080p HEVC video using QuickTime and mpv (installed via brew install --HEAD mpv ), again only 3% CPU usage.
  6. play back jellyfish-120-mbps-4k-uhd-hevc-10bit.mkv using mpv multiple times during screen recording, only 3% CPU usage.

my spec: i5-8400, RX 470, macOS 10.15.2, opencore-version REL-054-2019-12-13