(2015-10-21, 16:19)Carousel Wrote: Has anyone run conversions from H264 to H265 using new Intel Skylake kit and Windows 10? How long does it take to convert an original quality 20GB file?
Key (for those readers who may not know): AVC is h264 or x264. Likewise, HEVC is h265 or x265. x264 and x265 are specific open encoder implementations of their respective encoding formats (AVC & HEVC). h264 and h265 are not necessarily open implementations of the same encoding formats, but are often used to refer to AVC and HEVC formatted encodes or encoding. The AVC and HEVC formats set the rules, the h/x264/5 software/hardware follows those rules to compress images. It's simple but confusing at the same time. Here, I'll avoid using AVC & HEVC and stick to referring to the tools used, rather than reference the rules they fallow or the type of file they create.
You didn't ask specifically about QuickSync (QSV), but I just ran through several days of testing h/x265 on my new box; used various settings; did QSV/GPU and x265/CPU encoding; did 30 or so encodes of the same 2h:20m file; and did some comparative h/x264 encodes also.
In retrospection, in the future I'll test on shorter 1 or 10 minute files.
System details:
- Intel Skylake i5 6600K (stock),
- 16gb DDR4 RAM,
- Windows 10,
- Samsung Pro SSDs,
- with a sweet high end MOBO and a secondary discrete GPU (the INTEL GPU was only used for QSV encoding).
Encoding Software: Currently using StaxRip to test QSV, as it handles QSV better than Handbrake or other apps I've tested (more options & more up to date).
Original Video: 5gb 1080p, 2h:20m, x264 (ditched audio, so it didn't effect encode times). Bigger files will likely take longer, but these results paint a picture worth looking at.
Encode Settings / Constant Quality (CQ) = results (watch the Frames Per Second)
Code:
QSV h265 CQ25 fastest = 26min / 2.41gb 195 fps/avg
QSV h265 CQ25 balanced = 50min / 2.31gb 75 fps/avg
QSV h265 CQ25 best = 90min / 2.30gb 25 fps/avg (real-time encode)
Result Quality: Trash, all across the board. The video looks like a
very fast CQ30+ x264/CPU rip. They're garbage, and the files are even larger than the x264/CPU equivalents.
Conclusion: QuickSync (QSV) is not 'yet' meant to do video archiving, it's only ready for fast on-the-fly decoding & low-quality encoding/transcoding; which is great for streaming. But
if you're not Netflix, and you want quality archive video, stick to CPU rendering with software encoders (x265).
For Comparison, x265 (v1.8)
main profile via Handbrake (nightly), same system, same file:
Code:
CPU x265 CQ25 medium = 135min / ~1GB 23 fps/avg (real-time encode, an improvement in size & speed over x265 v1.5)
Results: Not really noticeably different from the original without really close inspection. At normal sitting distance only dark and fast paced scenes where a little more blocky. And the x265 v1.7 encode was substantially smaller than the equivalent x265 v1.5 encodes I had done previously during this test run; which encoded at ~15 fps. That's a big improvement in x265 encoding performance.
Note: h264 QSV also looks like crap on best settings. The QuickSync system isn't yet ready for archiving. I've read the same regarding other GPU encoding solutions too.
Also note: The quality of the CQ25 x265
medium encode was comparable to a CQ~28 x264
very slow encode that takes about the same amount of time, but the x265 is smaller; so a CQ~21 x265
medium is probably about the sweet spot for lossless looking lossy HD x265 encodes. The x265
slow setting doubled the encoding time using x265 v1.5.
Cheers.