DOKK / manpages / debian 12 / x265 / x265.1.en
x265(1) User Commands x265(1)

x256 - encoder for creating H.265/HEVC video streams

x265 [options] infile [-o] outfile

x256 is a commandline encoder for creating H.265/High Efficiency Video Coding (HEVC) video streams. infile can be a YUV or Y4M video stream. outfile will be used to store the raw HEVC bitstream.

Show this help text and exit

Bitstream output file name
Logging level: none error warning info debug full. Default info
Disable CLI progress reports
--[no-]cu-stats
Enable logging stats about distribution of cu across all modes. Default disabled
Comma separated log file, log level >= 3 frame log, else one line per run

Raw YUV or Y4M input file name. `-` for stdin
Force parsing of input stream as YUV4MPEG2 regardless of file extension
Source frame rate (float or num/denom), auto-detected if Y4M
Source picture size [w x h], auto-detected if Y4M
Bit-depth of input file. Default 8
Source color space: i420, i444 or i422, auto-detected if Y4M. Default: i420
Maximum number of frames to encode. Default all
First frame to encode
--[no-]interlace <bff|tff>
Indicate input pictures are interlace fields in temporal order. Default progressive
Enable dither if downscaling to 8 bit pixels. Default disabled

--[no-]ssim
Enable reporting SSIM metric scores. Default disabled
--[no-]psnr
Enable reporting PSNR metric scores. Default disabled

Enforce an encode profile: main, main10, mainstillpicture
Force a minimum required decoder level (as '5.0' or '50')
--[no-]high-tier
If a decoder level is specified, this modifier selects High tier of that level

Number of threads for thread pool (0: detect CPU core count, default)
Number of concurrently encoded frames. 0: auto-determined by core count
--[no-]wpp
Enable Wavefront Parallel Processing. Default enabled
--[no-]pmode
Parallel mode analysis. Default disabled
--[no-]pme
Parallel motion estimation. Default disabled
--[no-]asm <bool|int|string>
Override CPU detection. Default: auto

Trade off performance for compression efficiency. Default medium
ultrafast, superfast, veryfast, faster, fast, medium, slow, slower, veryslow, or placebo
Tune the settings for a particular type of source or situation:
psnr, ssim, zerolatency, or fastdecode

Maximum CU size (default: 64x64). Default 64
Max TU recursive depth for intra CUs. Default 1
Max TU recursive depth for inter CUs. Default 1
--[no-]rect
Enable rectangular motion partitions Nx2N and 2NxN. Default disabled
--[no-]amp
Enable asymmetric motion partitions, requires --rect. Default disabled

Level of RD in mode decision 0:least....6:full RDO. Default 3
Strength of psycho-visual rate distortion optimization, 0 to disable. Default 0.000000
Strength of psycho-visual optimization in quantization, 0 to disable. Default 0.000000
An integer value in range of 100 to 1000, which denotes strength of noise reduction. Default disabled
--[no-]tskip-fast
Enable fast intra transform skipping. Default disabled
--[no-]early-skip
Enable early SKIP detection. Default disabled
--[no-]fast-cbf
Enable early outs based on whether residual is coded. Default disabled

Enable weighted prediction in P slices. Default enabled
--[no-]weightb
Enable weighted prediction in B slices. Default disabled
--[no-]cu-lossless
Consider lossless mode in CU RDO decisions. Default disabled
--[no-]signhide
Hide sign bit of one coeff per TU (rdo). Default enabled
--[no-]tskip
Enable intra 4x4 transform skipping. Default disabled

Motion search method dia hex umh star full. Default 1
Amount of subpel refinement to perform (0:least .. 7:most). Default 2
Motion search range. Default 57
Maximum number of merge candidates. Default 2
--[no-]temporal-mvp
Enable temporal MV predictors. Default enabled

--[no-]strong-intra-smoothing Enable strong intra smoothing for 32x32 blocks. Default enabled

--[no-]constrained-intra
Constrained intra prediction (use only intra coded reference pixels) Default disabled
--[no-]b-intra
Enable intra in B frames in veryslow presets. Default disabled
--[no-]fast-intra
Enable faster search method for angular intra predictions. Default disabled
penalty for 32x32 intra TU in non-I slices. 0:disabled 1:RD-penalty 2:maximum. Default 0

--[no-]open-gop
Enable open-GOP, allows I slices to be non-IDR. Default enabled
Max IDR period in frames. -1 for infinite-gop. Default 250
Scenecuts closer together than this are coded as I, not IDR. Default: auto
Disable adaptive I-frame decision
How aggressively to insert extra I-frames. Default 40
Number of frames for frame-type lookahead (determines encoder latency) Default 20
Maximum number of consecutive b-frames (now it only enables B GOP structure) Default 4
Bias towards B frame decisions. Default 0
0 - none, 1 - fast, 2 - full (trellis) adaptive B frame scheduling. Default 2
--[no-]b-pyramid
Use B-frames as references. Default enabled
max number of L0 references to be allowed (1 .. 16) Default 3
Force frametypes and QPs for some or all frames Format of each line: framenumber frametype QP QP is optional (none lets x265 choose). Frametypes: I,i,P,B,b. QPs are restricted by qpmin/qpmax.

Target bitrate (kbps) for ABR (implied). Default 0
QP for P slices in CQP mode (implied). --ipratio and --pbration determine other slice QPs
Quality-based VBR (0-51). Default 28.000000
--[no-]lossless
Enable lossless: bypass transform, quant and loop filters globally. Default disabled
With CRF+VBV, limit RF to this value. Default 0.000000 May cause VBV underflows!
With CRF+VBV, limit RF to this value. Default 0.000000 this specifies a minimum rate factor value for encode!
Max local bitrate (kbit/s). Default 0
Set size of the VBV buffer (kbit). Default 0
Initial VBV buffer occupancy (fraction of bufsize or in kbits). Default 0.900000
Mode for Adaptive Quantization - 0:none 1:uniform AQ 2:auto variance. Default 2
Reduces blocking and blurring in flat and textured areas.(0 to 3.0). Default 1.000000
--[no-]cutree
Enable cutree for Adaptive Quantization. Default enabled
QP factor between I and P. Default 1.400000
QP factor between P and B. Default 1.300000
Chroma Cb QP Offset. Default 0
Chroma Cr QP Offset. Default 0
Filename for stats file in multipass pass rate control. Default x265_2pass.log
Multi pass rate control. 1: First pass, creates stats file 2: Last pass, does not overwrite stats file 3: Nth pass, overwrites stats file
--[no-]slow-firstpass
Enable a slow first pass in a multipass rate control mode. Default disabled
save - Dump analysis info into file, load - Load analysis buffers from the file. Default 0
Specify file name used for either dumping or reading analysis data.
Specify a file containing HM style quant scaling lists or 'default' or 'off'. Default: off
Specify a file containing replacement values for the lambda tables MAX_MAX_QP+1 floats for lambda table, then again for lambda2 table Blank lines and lines starting with hash(#) are ignored Comma is considered to be white-space

--[no-]lft
Enable Deblocking Loop Filter. Default enabled
--[no-]sao
Enable Sample Adaptive Offset. Default enabled
--[no-]sao-non-deblock
Use non-deblocked pixels, else right/bottom boundary areas skipped. Default disabled

Sample Aspect Ratio, the ratio of width to height of an individual pixel. Choose from 0=undef, 1=1:1("square"), 2=12:11, 3=10:11, 4=16:11, 5=40:33, 6=24:11, 7=20:11, 8=32:11, 9=80:33, 10=18:11, 11=15:11, 12=64:33, 13=160:99, 14=4:3, 15=3:2, 16=2:1 or custom ratio of <int:int>. Default 0
Add 'left,top,right,bottom' to the bitstream-level cropping rectangle
Specify whether it is appropriate for decoder to show cropped region: undef, show or crop. Default undef
Specify video format from undef, component, pal, ntsc, secam, mac. Default undef
Specify black level and range of luma and chroma signals as full or limited Default limited
Specify color primaries from undef, bt709, bt470m, bt470bg, smpte170m, smpte240m, film, bt2020. Default undef
Specify transfer characteristics from undef, bt709, bt470m, bt470bg, smpte170m, smpte240m, linear, log100, log316, iec61966-2-4, bt1361e, iec61966-2-1, bt2020-10, bt2020-12. Default undef
Specify color matrix setting from undef, bt709, fcc, bt470bg, smpte170m, smpte240m, GBR, YCgCo, bt2020nc, bt2020c. Default undef
Specify chroma sample location (0 to 5). Default of 0

--[no-]info
Emit SEI identifying encoder and parameters. Default enabled
--[no-]aud
Emit access unit delimiters at the start of each access unit. Default disabled
--[no-]hrd
Enable HRD parameters signalling. Default disabled
--[no-]repeat-headers
Emit SPS and PPS headers at each keyframe. Default disabled
Decoded Picture Hash SEI 0: disabled, 1: MD5, 2: CRC, 3: Checksum. Default 0

Reconstructed raw image YUV or Y4M output file name
Bit-depth of reconstructed raw image file. Defaults to input bit depth, or 8 if Y4M

Full documentation may be found at http://x265.readthedocs.org/en/default/cli.html.

November 2014 x265 1.4