x265 HEVC Encoder

[bjoker]

Thanks.
I tested an older version of ffmpeg/x265 and it worked fine.

Unfortunately the latest ffmpeg build still has x265 3.2+15. I think I will have to use external x265.
How could I pipe ffmpeg to external x265 for 2-pass please?

[Greenhorn]

I don't really know shell syntax, but what I'd normally do for standalone x265 would be convert my input files to decompressed .y4m with ffmpeg (ffmpeg -i example_input.file example_output.y4m), then convert the y4m using x265. (x265 example_output.y4m --my_settings -o example_output.hevc) You'll need enough free disk space for the whole .y4m to be stored, and the output will be a raw HEVC stream that needs to be muxed with ffmpeg again-- although that shouldn't pose any problems, unless you've got two buggy libraries in one ffmpeg at once.

[foxyshadis]

Originally Posted by Greenhorn

I don't really know shell syntax, but what I'd normally do for standalone x265 would be convert my input files to decompressed .y4m with ffmpeg (ffmpeg -i example_input.file example_output.y4m), then convert the y4m using x265. (x265 example_output.y4m --my_settings -o example_output.hevc) You'll need enough free disk space for the whole .y4m to be stored, and the output will be a raw HEVC stream that needs to be muxed with ffmpeg again-- although that shouldn't pose any problems, unless you've got two buggy libraries in one ffmpeg at once.

No ginormous intermediate file needed:

ffmpeg -i example_input.file -f yuv4mpegpipe -strict -2 - | x265 - -o example_output.hevc

That's going to be much faster than writing and reading to disk. The "strict -2" allows y4m to be greater than 8 bits, if necessary.

[nghiabeo20]

Does x265 have tuning for monochrome picture? And is it a good practice to convert a RGB black&white source to actual BW in an encode?

[nghiabeo20]

Originally Posted by foxyshadis

No ginormous intermediate file needed:

ffmpeg -i example_input.file -f yuv4mpegpipe -strict -2 - | x265 - -o example_output.hevc

That's going to be much faster than writing and reading to disk. The "strict -2" allows y4m to be greater than 8 bits, if necessary.

May I explain:

ffmpeg -i example_input.file -f yuv4mpegpipe -strict -2 -

The - makes ffmpeg send output to stdout.

x265 - -o example_output.hevc

The - makes x265 receive input from stdin.

The | (pipe) connects stdout to stdin.

[SaboraPie]

why this last versions are so slow. In v3.0 or earlier versions i was encoding at 1.2fps in veryslow mode, and now it is 0.42fps. Is maybe more efficient but much slower?

[Boulder]

The presets were changed at one point. The old "veryslow" became "slower" etc.

[Atak_Snajpera]

How to correctly signal HLG with x265?
So far I'm using following command line

--colorprim bt2020 --transfer bt2020-10 --colormatrix bt2020nc --atc-sei 18

but according to x265 docs there is also another required switch

--pic-struct <integer>
Set the picture structure and emits it in the picture timing SEI message. Values in the range 0..12. See D.3.3 of the HEVC spec. for a detailed explanation. Required for HLG (Hybrid Log Gamma) signalling. Not signalled by default.

What value has to be set there? Is --pic-struct 0 correct/needed for progressive frame?

[foxyshadis]

Yes, 0 for progressive. Odd that HLG requires it. Wouldn't transfer be arib-std-b67 for HLG?

[Atak_Snajpera]

Originally Posted by foxyshadis

Yes, 0 for progressive. Odd that HLG requires it. Wouldn't transfer be arib-std-b67 for HLG?

Mediainfo detects both so I'm not sure if arib-std-b67 is required...

--transfer bt2020-10

Transfer characteristics                 : HLG / BT.2020 (10-bit)

--transfer arib-std-b67

Transfer characteristics                 : HLG / HLG

[FranceBB]

This is the command line of an HLG encode I've done recently:

--colorprim bt2020 --transfer arib-std-b67 --colormatrix bt2020nc --atc-sei 18

I've never used --pic-struct, but the file has been recognized as an HLG one anyway.

But... Atak_Snajpera made it popping back up in my mind by asking about it, so... should I include --pic-struct 0 as well?

[excellentswordfight]

Originally Posted by FranceBB

This is the command line of an HLG encode I've done recently:

--colorprim bt2020 --transfer arib-std-b67 --colormatrix bt2020nc --atc-sei 18

I've never used --pic-struct, but the file has been recognized as an HLG one anyway.

But... Atak_Snajpera made it popping back up in my mind by asking about it, so... should I include --pic-struct 0 as well?

Originally Posted by Atak_Snajpera

Mediainfo detects both so I'm not sure if arib-std-b67 is required...

--transfer bt2020-10

Transfer characteristics                 : HLG / BT.2020 (10-bit)

--transfer arib-std-b67

Transfer characteristics                 : HLG / HLG

AFIK according to the specc its recommended for HLG that the fallback transfer function should flaged in "--transfer" and the HLG transfer i.e. arib-std-b67 / 18 with the preferred/alternative transfer characteristics flag (--atc-sei).

[hevc_enocder]

hello, may I have question?

What is right scrip for zones I tried this and i alaways get an error

--zones 9277,9328,crf=15.4/9381,9742,crf=15.4/27589,27647,crf=15.4/27885,28012,crf=15.4/28091,28174,crf=15.4/28285,28368,crf=15.4/36778,36848,crf=15.4/71142,71170,crf=15.4/72038,72097,crf=15.4/72401,72422,crf=15.4/157075,157141,crf=15.4/180290,180426,crf=15.4/188329,188459,crf=15.4/199320,199359,crf=15.4/199895,199990,crf=15.4/205184,205327,crf=15.4/221411,221500,crf=15.4/222062,222108,crf=15.4/237130,243727,crf=22

So my final setting is this:

--crf 16 --output-depth 10 --level-idc 5.1 --high-tier --ref 5 --bframes 12 --rd 6 --me 3 --subme 5 --merange 32 --ipratio 1.3 --pbratio 1.2 --weightb --b-intra --hevc-aq --no-rskip --qcomp 0.60 --psy-rd 1.07 --psy-rdoq 1.00 --ctu 64 --rc-lookahead 60 --deblock -3:-3 --cbqpoffs 0 --crqpoffs 0 --qg-size 8 --no-rskip --no-rect --no-amp --no-sao --no-open-gop --no-cutree --range limited --aud --repeat-headers --zones 9277,9328,crf=15.4/9381,9742,crf=15.4/27589,27647,crf=15.4/27885,28012,crf=15.4/28091,28174,crf=15.4/28285,28368,crf=15.4/36778,36848,crf=15.4/71142,71170,crf=15.4/72038,72097,crf=15.4/72401,72422,crf=15.4/157075,157141,crf=15.4/180290,180426,crf=15.4/188329,188459,crf=15.4/199320,199359,crf=15.4/199895,199990,crf=15.4/205184,205327,crf=15.4/221411,221500,crf=15.4/222062,222108,crf=15.4/237130,243727,crf=22

please can you tell me what is wrong about it? Thank you so much.

[Boulder]

I don't think x265 supports setting CRF in zones, you need to define q instead.

[RainyDog]

Originally Posted by hevc_enocder

hello, may I have question?

What is right scrip for zones I tried this and i alaways get an error

So my final setting is this:

please can you tell me what is wrong about it? Thank you so much.

Try replacing all instances of crf=15.4 in your script with b=1.3 (or find your preferred value instead of 1.3).

The 'b' stands for bitrate multiplier so 1.3 will increase the bitrate of the frames designated within zones by a factor of x1.3 (or +30%).

[Magik Mark]

Guys,

When encoding do you use ssim-rdo? Do you see any difference? When is the best time to use this? During 2pass perhaps? or CRF?

It takes longer when this is enabled.

[vpupkind]

Originally Posted by Boulder

I don't think x265 supports setting CRF in zones, you need to define q instead.

You can change crf (as well as some other parameters) per zone using the --zonefile option and a "sidecar file" with frame numbers and zone settings. You can change additional settings beyond crf/bitrate this way.

[vpupkind]

Originally Posted by Magik Mark

Guys,

When encoding do you use ssim-rdo? Do you see any difference? When is the best time to use this? During 2pass perhaps? or CRF?

It takes longer when this is enabled.

It is heavy but is totally worth it, IMO. We've seen meaningful quality improvements.

[microchip8]

Originally Posted by vpupkind

It is heavy but is totally worth it, IMO. We've seen meaningful quality improvements.

From my testing, it produces worse results in dark, mostly clean frames with a little of mosquito noise. Tested on Blade Runner 2049 starting from 6:00 minutes

[Greenhorn]

Oddly, enabling ssim-rd by itself will disable psy-rd, but if you manually specify both they'll both be used.