A while ago I tried to see what compression I could get out of screen recording losslessly to a scratch disk and encoding afterwards as slowly as I could wait. I didn't write any numbers down, but the difference in efficiency was significant. Some observations:
- Of the lossless encoders in OBS/libav, utvideo was the best in both CPU usage and efficiency, followed by lossless ultrafast x264.
- An SSD can handle even uncompressed 24bpp 1080p60, which is 375 MB/s. Typical screen content compresses well below the ~100 MB/s write speed of an HDD. Fullscreen video does not, instead gradually filling the write cache until either OOM or thrashing.
- For onscreen content, I prefer the bitrate tradeoff of keeping PC color range and not chroma subsampling.
This technique isn't as effective for this use case of recording several hours daily, since reencoding must be fast enough on average to keep up. Best to already have a home server (any spare desktop). Otherwise, use AOM codecs, known for poor multithreading, to encode at full speed without hogging CPU.
ps, temporal compression means that dropping framerate makes surprisingly little difference with modern codecs. But I really should be writing down the results of my ad hoc tests...
(3 days later): Necroing with a link to this serendipitous related submission about building a NAS for professional video editing from 40 TB of SSDs: https://news.ycombinator.com/item?id=32235158
Yea, on second thought, long term screen recording like this would be a terrible waste of silicon. At 150 MB/s, 46 days of nonstop recording would exhaust the entire 600 TBW of a 1 TB consumer SSD. And for fun: a high-end 500 GB SSD writing at 3500 MB/s could burn its 300 TBW in a single day, not counting the EoL slowdown.
Curiously, RAID 0 hard disks are perfect for such workloads, yet the blogger has still chosen to use consumer grade SSDs.
You can go even lower with other encoders (x265) + if you don't record audio at all