Quote:
Originally Posted by kolak
I've noticed the same odd thing.
x265 (in ffmpeg) + g=1 causes speed to drop to single fps (where long GOP is way faster). Why is this the case?
x264 is very fast in I frame only mode. Why is x265 (3.3 version if I remember well) so slow?
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Did you check thread utilization? Maybe the multithreading is not optimized for that scenario, and its working on one frame at a time.
Quote:
Originally Posted by easy2Bcheesy
Yes, agreed. It's brilliant. The question is how I can actually integrate this into workflow. To begin with, I'm looking for a quick transcode using NvEnc that will have a tiny GOP (I guess) to ensure fast scrubbing. But this could be the basis of a much faster workflow generally.
Something else I've discovered - with Nvidia at least, HEVC decode is a ton faster than h.264 - and that's comparing keyint=1, x264 vs x265. Interestingly the file sizes are basically the same with the same CRF factor.
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Not sure what settings that are possible to set with ffmpeg, have you tried
https://github.com/rigaya/NVEnc ?
Sounds like it should be possible with -strict-gop & --gop-len
edit. What bitrate are you roughly using for this scenario with 2160p60? 100Mbps? 4:2:0 or 4:2:2? 8bit or 10bit?
And I wondered what happened to Sonys pro HEVC codec, weren't they working on an XEVC format? I would assume that there would be an all intra profile of that.