SVT-HEVC vs X265

[sophisticles]

Shameless plug warning: For info on the source used and some reference encodes, see this thread:

https://forum.videohelp.com/threads/397870-The-most-comprehensive-AV1-encoding-test

While I was doing some SVT-AV1 test encodes for that thread, I ran across a bug with ffmpeg that I had not noticed before, namely no matter what crf value I passed to libx265 it seems to stick with the default crf 28. At this point i think it's a bug with ffmpeg itself that spans multiple versions, because I built ffmpeg+SVT-AV1 from the latest dev branch and it shows a similar bug where no matter what look ahead value is passed to ffmpeg for SVT-AV1 it sticks to the default value. I need to investigate further before I file a bug report.

Back to this, I decided to build the latest ffmpeg+SVT-AV1 to see if that SVT-AV1 bug showed up with the HEVC version and decided to run some tests.

Below you will find tests done with x264+medium+crf23 via Shotcut, this encode took 2min33sec; x265+medium+crf23 via Shotcut took 6:15sec.

For the SVT-HEVC encodes, I used the following command lines:

time ./ffmpeg -i "1080p.mp4" -c:v libsvt_hevc -rc 0 -qp 23 -preset 7 -tune 0 -an "/media/ck/960 GB SSD/1080p SVT-HEVC tune SQ.mp4" 2m35.779s

time ./ffmpeg -i "1080p.mp4" -c:v libsvt_hevc -rc 0 -qp 23 -preset 7 -tune 1 -an "/media/ck/960 GB SSD/1080p SVT-HEVC tune OQ.mp4" 2m29.254s

time ./ffmpeg -i "1080p.mp4" -c:v libsvt_hevc -rc 0 -qp 23 -preset 7 -tune 2 -an "/media/ck/960 GB SSD/1080p SVT-HEVC tune VMAF.mp4" 2m32.597s

time ./ffmpeg -i "1080p.mp4" -c:v libsvt_hevc -rc 0 -qp 23 -preset 4 -tune 0 -la_depth 40 -an "/media/ck/960 GB SSD/1080p SVT-HEVC.mp4" 6m47.564s

A bit of explaining, x264 and x265 have 10 presets available, ultrafast, superfast, veryfast, faster, fast, medium, slow, slower, very slow and placebo.

SVT-HEVC has from 0-12, inclusive, for a total of 13 presets, with a default of 7. It also has 3 different tune options, SQ (visually optimized), OQ (PSNR/SSIM optimized) and VMAF (vmaf optimized), with a default of OQ.

[sophisticles]

Having trouble uploading all the files, here's another one.

[sophisticles]

One more.

[sophisticles]

I just realized I forgot to upload the x264 and x265 encodes.

[ProWo]

I ran across a bug with ffmpeg that I had not noticed before, namely no matter what crf value I passed to libx265 it seems to stick with the default crf 28.

Not with the static builds (tested today with newest zeranoes x64 build for windows)

[sophisticles]

I ran across a bug with ffmpeg that I had not noticed before, namely no matter what crf value I passed to libx265 it seems to stick with the default crf 28.

Not with the static builds (tested today with newest zeranoes x64 build for windows)

I was talking about Ubuntu Linux 18 LTS with dynamically linked libraries.

And it's reproducable.