Quicktime Exports displaying artifacts only on HEVC 1080p exports

aditya18thm wrote:

I also think the GPU is failing.

If that is the case, and the Mac otherwise works, then one option is to use a workflow that encodes H.265 with CPU instead GPU.

For example you might do it with Handbrake, Shutter Encoder or ffmpeg.

I prefer ffmpeg via the Terminal. ffmpeg does not handle metadata (locations, captions etc) correctly so you must babysit it with exiftool. There are two options for that. I prefer the 1st where ffmpeg does not even try to preserve metadata and exiftool then copies metadata from the originals and also sets the file dates. In the examples below input is .mov and output is .mp4 (for other suffixes you must modify the commands):

Convert .mov to H.265 .mp4:

ffmpeg -i input.mov -c:v libx265 -crf 28 -preset medium -timecode 00:00:00:00 -tag:v hvc1 -c:a copy output.mp4

Convert .mov to H.265 .mp4 in batch mode:

for i in *.mov; do ffmpeg -i "$i" -c:v libx265 -crf 28 -preset medium -timecode 00:00:00:00 -tag:v hvc1 -c:a copy "${i%.*}".mp4; done

Copy metadata from the originals:

exiftool -m -overwrite_original -ext mp4 -api QuickTimeUTC=1 -api LargeFileSupport=1 -tagsFromFile %-.0f.mov -All:All '-Track*Date<QuickTime:CreateDate' '-Media*Date<QuickTime:CreateDate' '-FileCreateDate<QuickTime:CreateDate' '-FileModifyDate<QuickTime:CreateDate' .

...

Convert .mov to H.265 .mp4 and copy metadata (which needs fixing):

ffmpeg -i input.mov -c:v libx265 -crf 28 -preset medium -timecode 00:00:00:00 -tag:v hvc1 -c:a copy -movflags use_metadata_tags -map_metadata 0 output.mp4

Convert .mov to H.265 .mp4 in batch mode (which needs fixing):

for i in *.mov; do ffmpeg -i "$i" -c:v libx265 -crf 28 -preset medium -timecode 00:00:00:00 -tag:v hvc1 -c:a copy -movflags use_metadata_tags -map_metadata 0 "${i%.*}".mp4; done

Fix metadata:

exiftool -m -overwrite_original -ext mp4 -api LargeFileSupport=1 -Keys:All= -tagsFromFile @ -Keys:All .

Those '-crf 28 -preset medium' are the defaults. If you want more compression, and faster encoding increase -crf (The range is exponential, so increasing the CRF value +6 results in roughly half the bitrate / file size. Sane range is 17–28. Consider 18 to be visually lossless.) or use fast (Other options are ultrafast, superfast, veryfast, faster, fast, medium, slow, slower, veryslow, placebo. Compared to medium, veryslow requires 280% of the original encoding time, with only minimal improvements over slower in terms of quality).

> Handbrake using the Video Toolbox at CQ 62 [...] artifacts only occur for H265 portrait videos which have HDR

AFAIK "H.265 Video Toolbox" uses GPU while the plain H.265 uses CPU. Do you get artifacts with the latter encoder? I must test HDR/HLG portrait mode later because I do not have that kind of footage.

The corresponding ffmpeg GPU/CPU encode options are something like (GPU option with 2600K or even much lower produces pretty good output with 5-10x encoding speed compared to CPU option on my Mac mini 2018 Intel):

ffmpeg -i input.mov -c:v hevc_videotoolbox -profile 1 -b:v 6000K -timecode 00:00:00:00 -tag:v hvc1 -c:a copy output.mp4

ffmpeg -i input.mov -c:v libx265 -crf 28 -preset medium -timecode 00:00:00:00 -tag:v hvc1 -c:a copy output.mp4

Or to convert HDR/HLG to 8-bit SDR H.265 with CPU (ffmpeg7 recommended):

ffmpeg -i input.mov -vf zscale=t=linear:npl=250,format=gbrpf32le,zscale=p=bt709,tonemap=tonemap=hable:desat=0,zscale=t=bt709:m=bt709:r=tv,format=yuv420p -c:v libx265 -crf 28 -preset medium -timecode 00:00:00:00 -tag:v hvc1 -c:a copy output.mp4

Works for me as expected with Mac mini 2018, macOS 15.0.1. Maybe some 3rd party app intervenes (did you do a clean install on the external disk?)? Or maybe this is a hardware issue with the GPU?