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4K HDR videos, but within a small margin

I've been taking a look at sample 4K HDR videos, and this one caught my attention.

It's that I wanted to test out encoders' efficiency, and whether I can fit the video into file sizes limit of social media platforms (e.g. Discord.)

Part 1. Encoders' efficiency

TLDR:

Here's an example showcasing SVT-AV1's advantage on small bitrates (about 2.4 Mbps):

NVENC, on the other hand:

Also, here's NVENC at maximum quantization:

Part 2. Fitting video files

After a long fight with the encoders, I've chosen the below configuration for the file size limits:

  • 20 MiB (Discord): SVT-AV1, crf=43, preset=3, audio being AAC at 128 kb/s (42 slightly exceeds the limit.)

  • 100 MiB (GitHub): SVT-AV1-HDR, crf=32, preset=3, tune=0 (VQ), audio being AAC at 256 kb/s (31 slightly exceeds the limit.)

20 MiB limit:

100 MiB limit:

Also this is what happens if you send the video through mobile Discord:

(Note: Discord retains the color space information, while the video's thumbnail will not reflect the correct color, the player has a 50% chance of being able to do it. If you take a closer look, you'll see it's an 480p H264 video.)