#11657: libx265: -bufsize and -maxrate does not complement -x265-params vbv-
init=0.9
-------------------------------------+-------------------------------------
Reporter: Boopboop | Type: defect
Status: new | Priority: normal
Component: | Version: git-
undetermined | master
Keywords: libx265 vbv | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
-------------------------------------+-------------------------------------
Summary of the bug: specifying the general {{{-bufsize}}} and
{{{-maxrate}}} options, instead of using {{{-x265-params vbv-bufsize=:vbv-
maxrate=}}}, forces vbv-init=0.75, instead of working together with a
{{{-x265-params vbv-bufsize=0.9}}}, or leaving it out and letting it
default to x265's default 0.9.
How to reproduce:
{{{
% ffmpeg -report -loglevel 99 -to 1 -i DSC_0021.MOV -an -c:v libx265
-profile:v main10 -level:v 4.1 -bufsize 20M -maxrate 20M -preset:v
veryslow -x265-params pools=6:frame-threads=1:vbv-init=0.9 DSC_0021.mp4
ffmpeg version N-120196-g6b028859d9 Copyright (c) 2000-2025 the FFmpeg
developers
built with Apple clang version 17.0.0 (clang-1700.0.13.5)
configuration: --prefix=/opt/homebrew/Cellar/ffmpeg/HEAD-6b02885_3
--enable-shared --enable-pthreads --enable-version3 --cc=clang --host-
cflags= --host-ldflags='-Wl,-ld_classic' --enable-ffplay --enable-gnutls
--enable-gpl --enable-libaom --enable-libaribb24 --enable-libbluray
--enable-libdav1d --enable-libharfbuzz --enable-libjxl --enable-libmp3lame
--enable-libopus --enable-librav1e --enable-librist --enable-librubberband
--enable-libsnappy --enable-libsrt --enable-libssh --enable-libsvtav1
--enable-libtesseract --enable-libtheora --enable-libvidstab --enable-
libvmaf --enable-libvorbis --enable-libvpx --enable-libwebp --enable-
libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-lzma
--enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-
libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-
libopenjpeg --enable-libspeex --enable-libsoxr --enable-libzmq --enable-
libzimg --disable-libjack --disable-indev=jack --enable-videotoolbox
--enable-audiotoolbox --enable-neon
libavutil 60. 4.101 / 60. 4.101
libavcodec 62. 5.100 / 62. 5.100
libavformat 62. 1.101 / 62. 1.101
libavdevice 62. 0.100 / 62. 0.100
libavfilter 11. 1.100 / 11. 1.100
libswscale 9. 0.100 / 9. 0.100
libswresample 6. 0.100 / 6. 0.100
(snip)
x265 [info]: HEVC encoder version 4.1+1-1d117be
x265 [info]: build info [Mac OS X][clang 16.0.0][64 bit] 10bit
x265 [info]: using cpu capabilities: NEON Neon_DotProd Neon_I8MM
x265 [info]: Main 10 profile, Level-4 (High tier)
x265 [info]: Thread pool created using 6 threads
x265 [info]: Slices : 1
x265 [info]: frame threads / pool features : 1 / wpp(17 rows)
x265 [info]: Coding QT: max CU size, min CU size : 64 / 8
x265 [info]: Residual QT: max TU size, max depth : 32 / 3 inter / 3 intra
x265 [info]: ME / range / subpel / merge : star / 57 / 4 / 5
x265 [info]: Keyframe min / max / scenecut / bias : 25 / 250 / 40 / 5.00
x265 [info]: Lookahead / bframes / badapt : 40 / 8 / 2
x265 [info]: b-pyramid / weightp / weightb : 1 / 1 / 1
x265 [info]: References / ref-limit cu / depth : 5 / off / off
x265 [info]: AQ: mode / str / qg-size / cu-tree : 2 / 1.0 / 32 / 1
x265 [info]: Rate Control / qCompress : CRF-28.0 / 0.60
x265 [info]: VBV/HRD buffer / max-rate / init : 20000 / 20000 / 0.750
<= Here, init 0.75 instead of 0.9
x265 [info]: tools: rect amp rd=6 psy-rd=2.00 rdoq=2 psy-rdoq=1.00 rskip
mode=1
x265 [info]: tools: signhide tmvp b-intra strong-intra-smoothing deblock
sao
x265 [info]: tools: dhdr10-info
}}}
--
Ticket URL: <https://trac.ffmpeg.org/ticket/11657>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker
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