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1. Jerome (j@shitposter.world)'s status on Wednesday, 08-Jan-2025 00:35:04 JST Jerome

   I'm about to stress test YouTube encoders. I'm currently encoding 10 minutes of grayscale static at 2880x2160/60fps. I'm using x264 with a crf of 20 and getting just under 1.2 Gbps

   -c:v libx264 -crf 20 -preset fast -x264-params cabac=1:bframes=0:keyint=30:min-keyint=30:scenecut=0 -g 30 -pix_fmt yuv420p10le

   I turned off bframes because they weren't being used and it more than doubles encode speed. Turning off scene detection also increased performance and there weren't any scene cut iframes being placed so it shouldn't have any impact but speeding up encoding. I'm not using -pix_fnt gray10le because while it should be supported since it's included in the profile I don't know that it is for sure and I'd hate to have to reencode the video. As long as the video going in is grayscale then there shouldn't be a lot of practical differences anyway.

   However now I kind of want to test it just to see if it'll work.

   Anyway I'm curious just how heavily they'll compress my video.

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   • Alyx Hinata 🇹🇩🚫:unverified: (alyx@gameliberty.club)'s status on Wednesday, 08-Jan-2025 00:35:11 JST Alyx Hinata 🇹🇩🚫:unverified:

     in reply to

     @j From what I've seen of random videos that like to use TV static randomly edited in for effect, YouTube absolutely murders it.

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   • Alyx Hinata 🇹🇩🚫:unverified: (alyx@gameliberty.club)'s status on Wednesday, 08-Jan-2025 00:35:12 JST Alyx Hinata 🇹🇩🚫:unverified:

     in reply to

     @j Haven't checked any 4k videos of static, so can't say that I know. But I doubt the bitrate YouTube provides is worthy of being called 4k. Your video would probably fare better I guess if you open it on a relatively small screen (meaning an average monitor). But I think that on a large TV, the low bitrate might be more obvious.

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     matrix07012 :thotpatrol: repeated this.
   • Jerome (j@shitposter.world)'s status on Wednesday, 08-Jan-2025 00:35:13 JST Jerome

     in reply to

     • Alyx Hinata 🇹🇩🚫:unverified:
     @alyx how about in 4k?
   • Jerome (j@shitposter.world)'s status on Wednesday, 08-Jan-2025 00:35:20 JST Jerome

     in reply to

     • Alyx Hinata 🇹🇩🚫:unverified:
     @alyx so initial test was h264 120fps grey10le clip that was 5 minutes, 689 Mbps, and 24.1 GiB in size.
     
     This help article seemed to suggest that 120fps might work:
     https://support.google.com/youtube/answer/6124459
     
     What YouTube spat out was yuv240, vp9, 60fps, 381 Mbps, 13.3 GiB
     
     YouTube seems to have done a good job preserving all of the noise at 4k. It's artifact city at the lower resolution.
     
     That's wild.
     
     What's also cool is you can see what each resolution is capped at. 1440p seems to be capped at 65 Mbps while 1080p appears to be capped at 10Mbps. It also shows how YouTube is phasing out h264. They really only put effort into their 1080p h264 stream which makes sense as it's likely the most popular of the h264 streams by far.
     
     I wonder if different frame rates have different bitrate caps.
     
     But yeah 4k seems to get crf with no vbv cutoff limit.
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