Why do h264 renders have super visible artifacts/gliching?

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PaulF9

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Why do h264 renders have super visible artifacts/gliching?

PostTue Mar 28, 2023 6:54 am

Yesterday I had to export 4 times before I got a glitch-free 264 export. The previous 3 attempts all had super visible glitches/artifacting and thus the exported footage was unusable. This isn't uncommon either. Usually it doesn't take 4 tries but I've seen it often lately...

Anyone have any insight into why the exported renders produce such obvious glitching?

See my render settings here: https://imgur.com/a/sF2h1bA

I switched from NVIDIA Encoder to Intel Quick Sync not to long ago, because I read my 12th gen intel chip has a built in GPU with hardware 265 & 264 encoding that's better than NVIDIA. Maybe that's where things started glitching, not sure. I switched back to NVIDIA for now - will see.

In any case, using Quick Sync should work just as well I figure. It did for me in other editing software.

I know that in Resolve 264 exports are bad quality generally as illustrated by the example in this video: https://www.youtube.com/watch?v=KHxpU4U6FCI. But many of the exports I've been getting out of Resolve have not just been low quality, but completely unusable. I.E. straight to the trash bin.
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Charles Bennett

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Re: Why do h264 renders have super visible artifacts/glichin

PostTue Mar 28, 2023 1:49 pm

That video is the sort of quality I would expect after YTs recompression of a UHD video.
You will get much better quality on YouTube if you upload UHD and not HD, as the VP9 codec will be used for replay. I also now render and upload h265 which is a much better compression codec.
These are the render settings I use for h265.
Attachments
H265 Render Settings.jpg
H265 Render Settings.jpg (212.37 KiB) Viewed 647 times
Resolve Studio 18.6.6 build 7
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Jim Simon

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Re: Why do h264 renders have super visible artifacts/glichin

PostTue Mar 28, 2023 3:00 pm

The only time I've experienced glitches in my final renders are when I start with H.264 and export to H.264.

If I start with some proper professional footage (RAW, ProRes, etc.) I never get glitches.

Does that apply here?
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PaulF9

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Re: Why do h264 renders have super visible artifacts/glichin

PostTue Mar 28, 2023 3:39 pm

Jim Simon wrote:The only time I've experienced glitches in my final renders are when I start with H.264 and export to H.264.

If I start with some proper professional footage (RAW, ProRes, etc.) I never get glitches.

Does that apply here?

I use a GoPro so yeah I start with H265. I can't use anything that records proper professional footage as I need a tiny camera for what I do.
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PaulF9

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Re: Why do h264 renders have super visible artifacts/glichin

PostTue Mar 28, 2023 3:43 pm

Charles Bennett wrote:That video is the sort of quality I would expect after YTs recompression of a UHD video.
You will get much better quality on YouTube if you upload UHD and not HD, as the VP9 codec will be used for replay. I also now render and upload h265 which is a much better compression codec.
These are the render settings I use for h265.

The glitches happen before the upload to Youtube, they're in the rendered file from Resolve, with 265 too. I often render HD for preview purposes to share with others. Not sure if UHD (which I use to upload to Youtube) is affected as well but this glitching has so far been happening with those HD renders meant for preview/sharing purposes.
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Charles Bennett

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Re: Why do h264 renders have super visible artifacts/glichin

PostTue Mar 28, 2023 5:04 pm

If your recordings are Variable Frame Rate that is most likely the problem. Resolve does not like VFR. If they are VFR try transcoding the clips to a Constant Frame Rate in something like the free Shutter Encoder.
Resolve Studio 18.6.6 build 7
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PaulF9

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Re: Why do h264 renders have super visible artifacts/glichin

PostTue Mar 28, 2023 5:12 pm

Charles Bennett wrote:If your recordings are Variable Frame Rate that is most likely the problem. Resolve does not like VFR. If they are VFR try transcoding the clips to a Constant Frame Rate in something like the free Shutter Encoder.

I record in 25 FPS which is constant as far as I know.
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Charles Bennett

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Re: Why do h264 renders have super visible artifacts/glichin

PostTue Mar 28, 2023 5:38 pm

That doesn't make it constant. If you download and install MediaInfo, right click on one of your clips, and click on MediaInfo.
MediaInfo 1.jpg
MediaInfo 1.jpg (77.52 KiB) Viewed 567 times

It will open a page such as this. Next to Frame Rate Mode what does it say?
This is an example of one of my clips.
MediaInfo 2.jpg
MediaInfo 2.jpg (117.46 KiB) Viewed 567 times
Resolve Studio 18.6.6 build 7
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PaulF9

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Re: Why do h264 renders have super visible artifacts/glichin

PostTue Mar 28, 2023 6:49 pm

Ok I just did that, see the media info screensnhot here: https://imgur.com/a/QVnlVzK

It's constant.
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Uli Plank

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Re: Why do h264 renders have super visible artifacts/glichin

PostTue Mar 28, 2023 9:21 pm

Export Cineform or DNxHR and do the final encoding with HandBrake and its superior x264/265.
I don’t get such glitches as you describe on a Mac, but I go that route too (ProRes, of course).
No, an iGPU is not enough, and you can't use HEVC 10 bit 4:2:2 in the free version.

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Jim Simon

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Re: Why do h264 renders have super visible artifacts/glichin

PostThu Mar 30, 2023 8:07 pm

PaulF9 wrote:I use a GoPro so yeah I start with H265.
OK.

You might consider transcoding to Cineform, DNx or ProRes before editing. Those should export fine. (And they might even play better while editing. ;) )
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PaulF9

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Re: Why do h264 renders have super visible artifacts/glichin

PostSat Apr 01, 2023 8:45 am

The problem seems to have gone away since I switched from Intel Quick Sync back to NVIDIA for rednering - so far at least.

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