Yeah. h265 encoding is quite expensive so to be doing it live there is a tradeoff with speed/size. If you take a look at most cameras (I have Fujifilm XT4), if you're recording at 4k resolution with h265 at 60fps, you're looking at 400Mb/s. Which is still not much compared to something like say ProRes422 (~100MB/s) And nothing compared to raw uncompressed video (recorduing the literal raw video bytes coming uncompressed via HDMI cable) where you can get to something like 1GB/s even (https://www.gammaraydigital.com/blog/just-how-big-are-those-...). In fact in my above commands if you just keep the `rawvideo` format without passing any encoder and try to save to a file, you'll see how large these files can get!

Ever since I started playing with video recording I ended up getting a NAS with 10Gb/s ethernet card, definitely helps!