HW decoding on macOS introduces macroblock artifacts

[selfsimilar]

When 'Use Hardware Decoding' is active in Settings > Plex for Mac > Player, macroblocks or CTUs become much more visible, especially in very noisy parts of images like background. This creates a 'screendoor'-type effect where horizontal and vertical macroblock boundaries look like a regular grid over the image. The effect is more subtle in some scenes than others, but is more visible in video than in still frames, and especially when along borders from background to foreground for example when the foreground is moving slightly (like a person talking). I'll try to find a small video to attach that best illustrates the effect.

Test environment

PMS Version: 1.25.2.5319 PMP Version: Version: Plex for Mac version 1.44.0.2981-e2d72ac2 Platform: macOS v 12.3.1 - MacBook Pro (16", 2021) - Chip Apple M1 Max

Steps to reproduce

1. Enable 'Use Hardware Decoding'

Current behavior

Expected behavior

[selfsimilar]

Very noticeable in mkvs with the following settings: Codec H264 Bitrate 10163 kbps Bit Depth 8 Chroma Location topleft Chroma Subsampling 4:2:0 Coded Height 816 Coded Width 1920 Color Primaries bt709 Color Range tv Color Space bt709 Color Trc bt709 Frame Rate 23.976 fps Height 802 Level 4.0 Profile high Ref Frames 5 Scan Type progressive Width 1918 Display Title 1080p (H.264) Extended Display Title 1080p (H.264)

[selfsimilar]

Vertical artifacts very apparent in the suit in foreground on right half of the screen.

HW Decoding on

HW Decoding off

Severed.mkv.zip