x265 HEVC Encoder

[benwaggoner]

Originally Posted by rwill

What you can try is to pipe ffmpeg output into a file like so:

ffmpeg.exe -i %1 -pix_fmt yuv420p -f yuv4mpegpipe - > test.y4m

and then use test.y4m as an input file to a standalone x265.exe call to see what x265 does and debug that.

Yeah, I either output to .y4m or pipe into x265. It really simplifies debugging, and allows for specific x265 builds to be used.

Note that if you are doing 10-bit, you need to use:

ffmpeg.exe -i %1 -pix_fmt yuv420p10le -strict -1 -f yuv4mpegpipe - > test.y4m

And for piping:

ffmpeg.exe -i foo.mov -pix_fmt yuv420p10le -strict -1 -f yuv4mpegpipe - | x265.exe - --y4m

[asarian]

After painstakingly long denoising, I am finally ready to run the final x265-only process on The Fith Element (combined from 4x seperately denoised parts). I used the following command line:

VSPipe --y4m "f:\jobs\fifthfin.vpy" - | x265 --y4m --input - --preset medium --input-depth 10 --output-depth 10 --crf 10 --colorprim 9 --transfer 16 --colormatrix 9 --master-display "G(13250,34500)B(7500,3000)R(34000,16000)WP(15635,16450)L(40000000,50)" --max-cll "10000,724" --frames 181104 --chromaloc 2 --output "g:\video\fifthfin.hevc"

x265 outputs:

[0.8%] 1483/181104 frames, 4.180 fps, 18984 kb/s, 145.92 MB, eta 11:56:15, est.size 17819 MB

Says around 19 Mb/s, and estimated file-size of ca. 18 G. Those values seem extremely low, especially considering the source was 45 G. I even set CRF to 10. But it still seems too low.

Am I doing anything wrong?

[Boulder]

Looks ok to me. The CRF value's behaviour in HDR and SDR differs quite a lot as the HDR input is very flat and the encoder does not do any internal grading when analysing the video. I usually lower the CRF value by 4 with HDR encodes to get to the similar quality level.

[asarian]

Originally Posted by Boulder

Looks ok to me. The CRF value's behaviour in HDR and SDR differs quite a lot as the HDR input is very flat and the encoder does not do any internal grading when analysing the video. I usually lower the CRF value by 4 with HDR encodes to get to the similar quality level.

Thx. So, should I even go to CRF = 6? Or should 10 suffice? Overall, I'm very impressed with the compression ratio of x265.

[rwill]

Originally Posted by FranceBB

My new baby arrived today.
I look forward to take it for a spin with x265 (*_*)

Intel Xeon Gold, 56c/112th with AVX-512 and this time is in a server room with freezing cold temperatures, so I dare AVX512 to make it hot! xD

Too low base frequency, too many cores.

[_kermit]

Originally Posted by benwaggoner

Yeah, I either output to .y4m or pipe into x265. It really simplifies debugging, and allows for specific x265 builds to be used.

Note that if you are doing 10-bit, you need to use:

ffmpeg.exe -i %1 -pix_fmt yuv420p10le -strict -1 -f yuv4mpegpipe - > test.y4m

And for piping:

ffmpeg.exe -i foo.mov -pix_fmt yuv420p10le -strict -1 -f yuv4mpegpipe - | x265.exe - --y4m

thanks to both.

so, this would have been wrong?

ffmpeg.exe -i %1 -pix_fmt yuv420p -f yuv4mpegpipe -| x265.exe --input - --y4m ....

so I tried this:

ffmpeg.exe -i %1 -pix_fmt yuv420p10le -strict -1 -f yuv4mpegpipe - > %1.y4m
x265.exe --input %1.y4m --y4m ....

what I noticed:
- ffmpeg runs async in the background, continuously creating the file while x265 already starts processing.
- The file is huge, already 90GB out of a 20GB mkv

Is both expected and ok?

[Boulder]

Originally Posted by asarian

Thx. So, should I even go to CRF = 6? Or should 10 suffice? Overall, I'm very impressed with the compression ratio of x265.

I kind of would expect CRF 10 to look very good. Of course, it depends on your requirements and viewing distance so testing the results with different CRF in your real life viewing conditions is always recommended.

In addition to your settings, I'd set --no-sao to disable the infamous Smooth All Objects functionality. I'd probably also use --deblock -1:-1.

[FranceBB]

Originally Posted by rwill

Too low base frequency, too many cores.

Not really, I'm not an home user, I'm gonna be encoding professional UHD 12bit masterfiles coming from IMF Packages with MJPEG2000 RGB 12bit sources and I expect x265 to scale quite efficiently on all the cores. We'll see.

[rwill]

Originally Posted by _kermit

what I noticed:
- ffmpeg runs async in the background, continuously creating the file while x265 already starts processing.
- The file is huge, already 90GB out of a 20GB mkv

Is both expected and ok?

My intention was to check whether x265 would crash on the .y4m or complete. Because the input is the same as piped but pipe failed.

Regarding the size, you get ~6Mb per HD frame or ~24Mb per UHD frame. So at 24fps thats ~150 or ~600 Megabytes per second of video. So its not practical.

[Gravitator]

--ssim-rd - results in terribly poor image quality at low bitrate.

ffmpeg -i z:\space_6s.mkv -f yuv4mpegpipe - | x265 --y4m --input - --output-depth 10 --profile main10 --max-merge 1 --no-early-skip --rskip 0 --bframes 1 --ref 1 --bitrate 1000 --tune ssim --ssim-rd z:\ssim-rd.mkv

ffmpeg -i z:\space_6s.mkv -f yuv4mpegpipe - | x265 --y4m --input - --output-depth 10 --profile main10 --max-merge 1 --no-early-skip --rskip 0 --bframes 1 --ref 1 --bitrate 1000 --tune ssim z:\ssim-rd-off.mkv

Download an example > ssim-rd vs ssim-rd-off

[Boulder]

Originally Posted by Gravitator

--ssim-rd - results in terribly poor image quality at low bitrate.

ffmpeg -i z:\space_6s.mkv -f yuv4mpegpipe - | x265 --y4m --input - --output-depth 10 --profile main10 --max-merge 1 --no-early-skip --rskip 0 --bframes 1 --ref 1 --bitrate 1000 --tune ssim --ssim-rd z:\ssim-rd.mkv

ffmpeg -i z:\space_6s.mkv -f yuv4mpegpipe - | x265 --y4m --input - --output-depth 10 --profile main10 --max-merge 1 --no-early-skip --rskip 0 --bframes 1 --ref 1 --bitrate 1000 --tune ssim z:\ssim-rd-off.mkv

Download an example > ssim-rd vs ssim-rd-off

Originally Posted by x265 docs

can achieve significant gain in terms of objective quality metrics SSIM and PSNR

Which are not a measure for visual quality I'm afraid.

[Gravitator]

Originally Posted by Boulder

Which are not a measure for visual quality I'm afraid.

The problem is in the combination of settings.

[excellentswordfight]

Originally Posted by FranceBB

Not really, I'm not an home user, I'm gonna be encoding professional UHD 12bit masterfiles coming from IMF Packages with MJPEG2000 RGB 12bit sources and I expect x265 to scale quite efficiently on all the cores. We'll see.

I get decent utilization up to about 24C/48T for UHD, we ofc have servers/clusters that exceeds that as we can push multiple encodes through them at the same time.

Could you please report back what frequency you are getting under high utilization with and without AVX512? We are moving to Epyc on all our encoding hardware, the frequency under load are just much higher compared to Intel in simulair price bracket were 32/64 CPU:s can push over 3Ghz under load.

[Boulder]

Originally Posted by Gravitator

The problem is in the combination of settings.

Have you found out which particular one triggers it?

Not that I expect them to fix it even if you reported the issue at the bug tracker

[_kermit]

Originally Posted by rwill

My intention was to check whether x265 would crash on the .y4m or complete. Because the input is the same as piped but pipe failed.

Regarding the size, you get ~6Mb per HD frame or ~24Mb per UHD frame. So at 24fps thats ~150 or ~600 Megabytes per second of video. So its not practical.

that's fine, I use pipeline again and with that command line the error is gone.

thanks!

[benwaggoner]

Originally Posted by Boulder

I kind of would expect CRF 10 to look very good. Of course, it depends on your requirements and viewing distance so testing the results with different CRF in your real life viewing conditions is always recommended.

In addition to your settings, I'd set --no-sao to disable the infamous Smooth All Objects functionality. I'd probably also use --deblock -1:-1.

I've seen quality improvements with some unusual sources down to CRF 12, certainly. But never anything below 10.

[benwaggoner]

Originally Posted by K.i.N.G

Thank you, I've lowered it to 16 and will report back when its finished.

I can live with 'slight' bitrate increases (which is perfectly understandable).

Also, are you looking at still frames of moving video? x265 and other encoders are tuned to optimize quality in-motion. Lots of things that look not-great when paused will go unnoticed when playing at full speed.

Reducing --ipratio and --pbratio can help with this as well, also increasing bitrate. There's also the experimental --aq-motion which might be worth poking out if you have idle encoding time.

I'm not sure why reducing --qg-size would help. That specifies the block size in which QP be can be varied, and is more useful for improving quality of content of highly variable detail.

[asarian]

Originally Posted by Boulder

I kind of would expect CRF 10 to look very good. Of course, it depends on your requirements and viewing distance so testing the results with different CRF in your real life viewing conditions is always recommended.

In addition to your settings, I'd set --no-sao to disable the infamous Smooth All Objects functionality. I'd probably also use --deblock -1:-1.

Thx, I will add your parameters for the next encoding.

[asarian]

Originally Posted by benwaggoner

I've seen quality improvements with some unusual sources down to CRF 12, certainly. But never anything below 10.

I never went below 14 with x264 (and even then friends declared me insane). Since I read the quality of x265 can often be lower, esecially in dark spots, I went as low as 10. With 10 more hours to gp on the final run, file size is estimated at 44G now, which I still deem acceptable. Shouldn't become much larger, though.

[StormMeows]

Hey guys new here and really looking for some solid advice. I would greatly appreciate it.

I am in the process of backing up my Blu-Ray Collection that has a ton of movies in it. My CPU is pretty good, but for x265 especially, one movie would take a crazy amount of time. I have a lot of space on my NAS but not enough for full REMUXES of every movie so I want to encode the video ONLY. I want to passthrough the original Blu-Ray and 4K UHD Audio (DTS-MA/Dolby Atmos/True HD, etc). Can you guys please offer advice on the best program and settings to use? I know I want to use a really low CRF, and will keep the settings constant for every movie. In the event that the file ends up being just as big or bigger than the original, I can keep the original file instead of the encoded one. I prefer to keep the video as untouched as possible so no cropping or killing the grain, etc. I will watch the movies on something like Plex or KODI (direct play).

*Also, I should mentioned I tried Handbrake, but it seems limited on settings. For instance, you can only choose up to "Slow" as the slowest setting (no slower or placebo option). I would like a program easy to use that I can just run and not have to worry about checking screenshots for each movie, especially since I have so many movies.

Thank you guys so much!