# Use AV1 + Opus

These are best formats now. These are free formats. These have ver
y high compression and high quality. For an anime (12 episodes), 7
20p is about 2GB. 1080p is about 3GB. 1080p 10bit is about 6-7GB.
For quality, AV1 is more efficient than HEVC by 30%. Opus has the
lowest latency.

AV1 is not currently mainstream. But at least youtube supports it.
To download AV1 + Opus with yt-dlp, put

``````````````````````````````````````````````````````````````````
--prefer-free-formats
-S '+codec:av1:opus'
``````````````````````````````````````````````````````````````````

on your yt-dlp config file. This will make AV1 > VP9 > AVC for vid
eo, Opus > AAC for audio. VP9 is what you should use, if you can't
use AV1. So this makes sense.