tom's has done a nice comparison between the two and as expected x265 wins hands down:
http://www.tomshardware.com/reviews/x265-hevc-encoder,3565.html
the important points to take away from the article are these:
It’s currently x86-only (albeit with support for advanced instruction sets like AVX2), lacks B-frame support (preventing it from achieving maximum compression), and doesn’t yet include some of the optimizations taken from x264 (like look-ahead and rate control).
With that in mind, let’s take a quick peek at how pre-alpha x265 stacks up against the well-optimized x264. For this one, we're using the following command: x264 --preset placebo --sar 1920:1080 --fps 24 --frames 500 --psnr -o x264Kimonoq24.264 Kimono1_1920x1080_24.yuv, again with quantization parameters between 24 and 42. We could have used the --tune psnr switch to generate higher values, though this negatively affects subjective quality compared to the settings used here.
x265 --input Kimono1_1920x1080_24.yuv --width 1920 --height 1080 --rate 24 -f 240 -o q24_Kimono1.out --rect --max-merge 1 --hash 1 --wpp --gops 4 --tu-intra-depth 1 --tu-inter-depth 2 --no-tskip, with quantization parameters between 24 and 42. It's notable that we're employing GOP (Group Of Picture)-level parallelism to keep our quad-core -4770K busy. I'm also adding the --cpuid switch to control the instruction sets being used.
performance is abysmal as the moment, i think they said they are getting 4 fps on a 4770k though the guys behind x265 hope to be able to see real time 1080p30 encodes on xeon based server with 16 physical cores by next month.
the good thing is that tom's didn't skimp on the x264 settings, they could have used somewhat more aggressive settings but "placebo" should leave little wiggle room for x264 apologists to moan about.
i can't help but think that this would be a perfect time for nvidia to strike with a cuda based h265 reference encoder of their own; at 4 fps with the fastest quad core haswell, a gpu powered h265 encoder that can hit say half real time speed on a mid range video card would certainly be a big selling point for nvidia.
edit: extremetech also did a comparison and in there's x265's win was by a larger margin:
http://www.extremetech.com/computing/162027-h-265-benchmarked-does-the-next-generation...o-expectations
http://www.tomshardware.com/reviews/x265-hevc-encoder,3565.html
the important points to take away from the article are these:
Quote:
It’s currently x86-only (albeit with support for advanced instruction sets like AVX2), lacks B-frame support (preventing it from achieving maximum compression), and doesn’t yet include some of the optimizations taken from x264 (like look-ahead and rate control).
Quote:
With that in mind, let’s take a quick peek at how pre-alpha x265 stacks up against the well-optimized x264. For this one, we're using the following command: x264 --preset placebo --sar 1920:1080 --fps 24 --frames 500 --psnr -o x264Kimonoq24.264 Kimono1_1920x1080_24.yuv, again with quantization parameters between 24 and 42. We could have used the --tune psnr switch to generate higher values, though this negatively affects subjective quality compared to the settings used here.
Quote:
x265 --input Kimono1_1920x1080_24.yuv --width 1920 --height 1080 --rate 24 -f 240 -o q24_Kimono1.out --rect --max-merge 1 --hash 1 --wpp --gops 4 --tu-intra-depth 1 --tu-inter-depth 2 --no-tskip, with quantization parameters between 24 and 42. It's notable that we're employing GOP (Group Of Picture)-level parallelism to keep our quad-core -4770K busy. I'm also adding the --cpuid switch to control the instruction sets being used.
the good thing is that tom's didn't skimp on the x264 settings, they could have used somewhat more aggressive settings but "placebo" should leave little wiggle room for x264 apologists to moan about.
i can't help but think that this would be a perfect time for nvidia to strike with a cuda based h265 reference encoder of their own; at 4 fps with the fastest quad core haswell, a gpu powered h265 encoder that can hit say half real time speed on a mid range video card would certainly be a big selling point for nvidia.
edit: extremetech also did a comparison and in there's x265's win was by a larger margin:
http://www.extremetech.com/computing/162027-h-265-benchmarked-does-the-next-generation...o-expectations