Need advice encoding to HEVC x265 10bits with FFMPEG.

[Unknown01]

I have seen video releases that take bluray sizes (2.2gb per episode of 23 minutes) to 196mb.
All this without any noticeable loss in quality.

It would seem the encoder does this by encoding to HEVC x265 10bits.

General
Unique ID                                : 208913498364140972766772815030478702390 (0x9D2B46B6EB36133062E835ED897C0736)
Complete name                           : ----
Format                                   : Matroska
Format version                           : Version 4
File size                                : 197 MiB
Duration                                 : 23 min 44 s
Overall bit rate                         : 1 158 kb/s
Frame rate                               : 23.976 FPS
Encoded date                             : 2024-08-17 19:25:46 UTC
Writing application                      : mkvmerge v85.0 ('Shame For You') 64-bit
Writing library                          : libebml v1.4.5 + libmatroska v1.7.1 / Lavf58.76.100
Attachments                              : PWScript09.ttf / rabiohead.ttf / Roboto-Medium.ttf / Roboto-Regular.ttf / SpinnerRackProBB-Reg.otf / SpongeMeetsVanilla.ttf / SS Soapy Hands Bold.otf / SS Soapy Hands Regular.otf / arial.ttf / Boba Date-Bold.otf / CCSamaritanTall-Bold.otf / impact.ttf / Lato-Black.ttf / Lato-Bold.ttf / Lato-BoldItalic.ttf

Video
ID                                       : 1
Format                                   : HEVC
Format/Info                              : High Efficiency Video Coding
Format profile                           : Main 10@L5@Main
Codec ID                                 : V_MPEGH/ISO/HEVC
Duration                                 : 23 min 41 s
Bit rate                                 : 1 032 kb/s
Width                                    : 1 920 pixels
Height                                   : 1 080 pixels
Display aspect ratio                     : 16:9
Frame rate mode                          : Constant
Frame rate                               : 23.976 (24000/1001) FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 10 bits
Bits/(Pixel*Frame)                       : 0.021
Stream size                              : 175 MiB (89%)
Title                                    : [Judas] x265 10b
Writing library                          : x265 3.5+19-8003e4382:[Windows][MSVC 1929][64 bit] 10bit
Encoding settings                        : cpuid=1111039 / frame-threads=5 / numa-pools=+ / wpp / pmode / no-pme / no-psnr / no-ssim / log-level=2 / csv / csv-log-level=0 / input-csp=1 / input-res=1920x1080 / interlace=0 / total-frames=34072 / level-idc=0 / high-tier=1 / uhd-bd=0 / ref=6 / no-allow-non-conformance / no-repeat-headers / annexb / no-aud / no-eob / no-eos / no-hrd / info / hash=0 / no-temporal-layers / open-gop / min-keyint=24 / keyint=240 / gop-lookahead=0 / bframes=8 / b-adapt=2 / b-pyramid / bframe-bias=0 / rc-lookahead=120 / lookahead-slices=4 / scenecut=40 / no-hist-scenecut / radl=0 / no-splice / no-intra-refresh / ctu=64 / min-cu-size=8 / rect / no-amp / max-tu-size=32 / tu-inter-depth=4 / tu-intra-depth=4 / limit-tu=0 / rdoq-level=2 / dynamic-rd=0.00 / no-ssim-rd / signhide / no-tskip / nr-intra=0 / nr-inter=0 / no-constrained-intra / strong-intra-smoothing / max-merge=3 / limit-refs=0 / limit-modes / me=3 / subme=4 / merange=57 / temporal-mvp / no-frame-dup / no-hme / weightp / weightb / no-analyze-src-pics / deblock=-1:-1 / sao / no-sao-non-deblock / rd=4 / selective-sao=4 / no-early-skip / rskip / no-fast-intra / no-tskip-fast / no-cu-lossless / b-intra / no-splitrd-skip / rdpenalty=0 / psy-rd=0.50 / psy-rdoq=1.10 / no-rd-refine / no-lossless / cbqpoffs=-1 / crqpoffs=-1 / rc=crf / crf=21.0 / qcomp=0.65 / qpstep=4 / stats-write=0 / stats-read=0 / ipratio=1.40 / pbratio=1.30 / aq-mode=3 / aq-strength=0.70 / cutree / zone-count=0 / no-strict-cbr / qg-size=32 / no-rc-grain / qpmax=69 / qpmin=0 / no-const-vbv / sar=0 / overscan=0 / videoformat=5 / range=0 / colorprim=2 / transfer=2 / colormatrix=2 / chromaloc=0 / display-window=0 / cll=0,0 / min-luma=0 / max-luma=1023 / log2-max-poc-lsb=8 / vui-timing-info / vui-hrd-info / slices=1 / no-opt-qp-pps / no-opt-ref-list-length-pps / no-multi-pass-opt-rps / scenecut-bias=0.05 / hist-threshold=0.03 / no-opt-cu-delta-qp / no-aq-motion / no-hdr10 / no-hdr10-opt / no-dhdr10-opt / no-idr-recovery-sei / analysis-reuse-level=0 / analysis-save-reuse-level=0 / analysis-load-reuse-level=0 / scale-factor=0 / refine-intra=0 / refine-inter=0 / refine-mv=1 / refine-ctu-distortion=0 / no-limit-sao / ctu-info=0 / no-lowpass-dct / refine-analysis-type=0 / copy-pic=1 / max-ausize-factor=1.0 / no-dynamic-refine / no-single-sei / no-hevc-aq / no-svt / no-field / qp-adaptation-range=1.00 / scenecut-aware-qp=0conformance-window-offsets / right=0 / bottom=0 / decoder-max-rate=0 / no-vbv-live-multi-pass
Language                                 : Japanese
Default                                  : Yes
Forced                                   : No

Audio
ID                                       : 2
Format                                   : Opus
Codec ID                                 : A_OPUS
Duration                                 : 23 min 41 s
Bit rate                                 : 108 kb/s
Channel(s)                               : 2 channels
Channel layout                           : L R
Sampling rate                            : 48.0 kHz
Frame rate                               : 50.000 FPS (960 SPF)
Compression mode                         : Lossy
Stream size                              : 18.3 MiB (9%)
Title                                    : [Judas] JAP Stereo (Opus 112Kbps)
Language                                 : Japanese
Default                                  : Yes
Forced                                   : No

The encoding settings are pretty confusing:

cpuid=1111039 / frame-threads=5 / numa-pools=+ / wpp / pmode / no-pme / no-psnr / no-ssim / log-level=2 / csv / csv-log-level=0 / input-csp=1 / input-res=1920x1080 / interlace=0 / total-frames=34072 / level-idc=0 / high-tier=1 / uhd-bd=0 / ref=6 / no-allow-non-conformance / no-repeat-headers / annexb / no-aud / no-eob / no-eos / no-hrd / info / hash=0 / no-temporal-layers / open-gop / min-keyint=24 / keyint=240 / gop-lookahead=0 / bframes=8 / b-adapt=2 / b-pyramid / bframe-bias=0 / rc-lookahead=120 / lookahead-slices=4 / scenecut=40 / no-hist-scenecut / radl=0 / no-splice / no-intra-refresh / ctu=64 / min-cu-size=8 / rect / no-amp / max-tu-size=32 / tu-inter-depth=4 / tu-intra-depth=4 / limit-tu=0 / rdoq-level=2 / dynamic-rd=0.00 / no-ssim-rd / signhide / no-tskip / nr-intra=0 / nr-inter=0 / no-constrained-intra / strong-intra-smoothing / max-merge=3 / limit-refs=0 / limit-modes / me=3 / subme=4 / merange=57 / temporal-mvp / no-frame-dup / no-hme / weightp / weightb / no-analyze-src-pics / deblock=-1:-1 / sao / no-sao-non-deblock / rd=4 / selective-sao=4 / no-early-skip / rskip / no-fast-intra / no-tskip-fast / no-cu-lossless / b-intra / no-splitrd-skip / rdpenalty=0 / psy-rd=0.50 / psy-rdoq=1.10 / no-rd-refine / no-lossless / cbqpoffs=-1 / crqpoffs=-1 / rc=crf / crf=21.0 / qcomp=0.65 / qpstep=4 / stats-write=0 / stats-read=0 / ipratio=1.40 / pbratio=1.30 / aq-mode=3 / aq-strength=0.70 / cutree / zone-count=0 / no-strict-cbr / qg-size=32 / no-rc-grain / qpmax=69 / qpmin=0 / no-const-vbv / sar=0 / overscan=0 / videoformat=5 / range=0 / colorprim=2 / transfer=2 / colormatrix=2 / chromaloc=0 / display-window=0 / cll=0,0 / min-luma=0 / max-luma=1023 / log2-max-poc-lsb=8 / vui-timing-info / vui-hrd-info / slices=1 / no-opt-qp-pps / no-opt-ref-list-length-pps / no-multi-pass-opt-rps / scenecut-bias=0.05 / hist-threshold=0.03 / no-opt-cu-delta-qp / no-aq-motion / no-hdr10 / no-hdr10-opt / no-dhdr10-opt / no-idr-recovery-sei / analysis-reuse-level=0 / analysis-save-reuse-level=0 / analysis-load-reuse-level=0 / scale-factor=0 / refine-intra=0 / refine-inter=0 / refine-mv=1 / refine-ctu-distortion=0 / no-limit-sao / ctu-info=0 / no-lowpass-dct / refine-analysis-type=0 / copy-pic=1 / max-ausize-factor=1.0 / no-dynamic-refine / no-single-sei / no-hevc-aq / no-svt / no-field / qp-adaptation-range=1.00 / scenecut-aware-qp=0conformance-window-offsets / right=0 / bottom=0 / decoder-max-rate=0 / no-vbv-live-multi-pass

How can i translate this to FFMPEG?

I guess the bare basis would be something like this if i want to use my GPU (yes, i want to):

ffmpeg -y -vsync 0 -hwaccel cuda -hwaccel_output_format cuda -i input.mp4 -c:v hevc_nvenc -preset slow -profile:v main10 -rc:v vbr_hq -b:v 0 -cq 19 -c:a copy output.mkv

The issue is that this syntax gives me 3x the size when i am looking to reduce the size while retaining as much of the original quality.
I want to squish the size while keeping the most quality possible.

Any advice?

[pandy]

This can be helpful:
https://trac.ffmpeg.org/wiki/Encode/H.265
https://x265.readthedocs.io/en/master/presets.html
https://x265.readthedocs.io/en/master/cli.html

Check options vs presets to get idea behind commandline in your file source - not every setting can be reasonable - sometimes people use weird settings only to mark their tree...

To copy your setting you need to use https://trac.ffmpeg.org/wiki/Encode/H.265#PassingOptions - there can be syntax differences (like x265 'no-lossless' in ffmpeg can be for example '-x265-params "no_lossless=1" ' - you need to figure this by yourself or dig for examples).

[buzz1891]

i want to use my GPU (yes, i want to) ... The issue is that this syntax gives me 3x the size when

x265 is a particular implementation of HEVC encoder, and it's way more advanced in comparison to what any GPU supports.
Yon can't have both, you have to chose either speed or size/quality.

[Salivity]

using a decent Constant Rate Factor (CRF) setting as well as preset veryslow should give some really decent results. I created an online tool to encode to h264 just click export instead of execute and change libx264 -> libx265 in the output command. All the settings for h264 and h265 seem to be the same. You can use this tool here https://davidclews.com/article/303.html