Provided by: x265_3.5-2_amd64 
NAME
x256 - encoder for creating H.265/HEVC video streams
SYNOPSIS
x265 [options] infile [-o] outfile
DESCRIPTION
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.
Executable Options:
-h/--help
Show this help text and exit
Output Options:
-o/--output <filename>
Bitstream output file name
--log-level <string>
Logging level: none error warning info debug full. Default info
--no-progress
Disable CLI progress reports
--[no-]cu-stats
Enable logging stats about distribution of cu across all modes. Default disabled
--csv <filename>
Comma separated log file, log level >= 3 frame log, else one line per run
Input Options:
--input <filename>
Raw YUV or Y4M input file name. `-` for stdin
--y4m Force parsing of input stream as YUV4MPEG2 regardless of file extension
--fps <float|rational>
Source frame rate (float or num/denom), auto-detected if Y4M
--input-res WxH
Source picture size [w x h], auto-detected if Y4M
--input-depth <integer>
Bit-depth of input file. Default 8
--input-csp <string>
Source color space: i420, i444 or i422, auto-detected if Y4M. Default: i420
-f/--frames <integer>
Maximum number of frames to encode. Default all
--seek <integer>
First frame to encode
--[no-]interlace <bff|tff>
Indicate input pictures are interlace fields in temporal order. Default progressive
--dither
Enable dither if downscaling to 8 bit pixels. Default disabled
Quality reporting metrics:
--[no-]ssim
Enable reporting SSIM metric scores. Default disabled
--[no-]psnr
Enable reporting PSNR metric scores. Default disabled
Profile, Level, Tier:
--profile <string>
Enforce an encode profile: main, main10, mainstillpicture
--level-idc <integer|float>
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
Threading, performance:
--threads <integer>
Number of threads for thread pool (0: detect CPU core count, default)
-F/--frame-threads <integer>
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
Presets:
-p/--preset <string>
Trade off performance for compression efficiency. Default medium
ultrafast, superfast, veryfast, faster, fast, medium, slow, slower, veryslow, or
placebo
-t/--tune <string>
Tune the settings for a particular type of source or situation:
psnr, ssim, zerolatency, or fastdecode
Quad-Tree size and depth:
-s/--ctu <64|32|16>
Maximum CU size (default: 64x64). Default 64
--tu-intra-depth <integer>
Max TU recursive depth for intra CUs. Default 1
--tu-inter-depth <integer>
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
Analysis:
--rd <0..6>
Level of RD in mode decision 0:least....6:full RDO. Default 3
--psy-rd <0..2.0>
Strength of psycho-visual rate distortion optimization, 0 to disable. Default
0.000000
--psy-rdoq <0..50.0>
Strength of psycho-visual optimization in quantization, 0 to disable. Default
0.000000
--nr <integer>
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
Coding tools:
-w/--[no-]weightp
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
Temporal / motion search options:
--me <string>
Motion search method dia hex umh star full. Default 1
-m/--subme <integer>
Amount of subpel refinement to perform (0:least .. 7:most). Default 2
--merange <integer>
Motion search range. Default 57
--max-merge <1..5>
Maximum number of merge candidates. Default 2
--[no-]temporal-mvp
Enable temporal MV predictors. Default enabled
Spatial / intra options:
--[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
--rdpenalty <0..2>
penalty for 32x32 intra TU in non-I slices. 0:disabled 1:RD-penalty 2:maximum.
Default 0
Slice decision options:
--[no-]open-gop
Enable open-GOP, allows I slices to be non-IDR. Default enabled
-I/--keyint <integer>
Max IDR period in frames. -1 for infinite-gop. Default 250
-i/--min-keyint <integer>
Scenecuts closer together than this are coded as I, not IDR. Default: auto
--no-scenecut
Disable adaptive I-frame decision
--scenecut <integer>
How aggressively to insert extra I-frames. Default 40
--rc-lookahead <integer>
Number of frames for frame-type lookahead (determines encoder latency) Default 20
--bframes <integer>
Maximum number of consecutive b-frames (now it only enables B GOP structure)
Default 4
--bframe-bias <integer>
Bias towards B frame decisions. Default 0
--b-adapt <0..2>
0 - none, 1 - fast, 2 - full (trellis) adaptive B frame scheduling. Default 2
--[no-]b-pyramid
Use B-frames as references. Default enabled
--ref <integer>
max number of L0 references to be allowed (1 .. 16) Default 3
--qpfile <string>
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.
Rate control, Quantization:
--bitrate <integer>
Target bitrate (kbps) for ABR (implied). Default 0
-q/--qp <integer>
QP for P slices in CQP mode (implied). --ipratio and --pbration determine other
slice QPs
--crf <float>
Quality-based VBR (0-51). Default 28.000000
--[no-]lossless
Enable lossless: bypass transform, quant and loop filters globally. Default
disabled
--crf-max <float>
With CRF+VBV, limit RF to this value. Default 0.000000 May cause VBV underflows!
--crf-min <float>
With CRF+VBV, limit RF to this value. Default 0.000000 this specifies a minimum
rate factor value for encode!
--vbv-maxrate <integer>
Max local bitrate (kbit/s). Default 0
--vbv-bufsize <integer>
Set size of the VBV buffer (kbit). Default 0
--vbv-init <float>
Initial VBV buffer occupancy (fraction of bufsize or in kbits). Default 0.900000
--aq-mode <integer>
Mode for Adaptive Quantization - 0:none 1:uniform AQ 2:auto variance. Default 2
--aq-strength <float>
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
--ipratio <float>
QP factor between I and P. Default 1.400000
--pbratio <float>
QP factor between P and B. Default 1.300000
--cbqpoffs <integer>
Chroma Cb QP Offset. Default 0
--crqpoffs <integer>
Chroma Cr QP Offset. Default 0
--stats
Filename for stats file in multipass pass rate control. Default x265_2pass.log
--pass 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
--analysis-mode <string|int>
save - Dump analysis info into file, load - Load analysis buffers from the file.
Default 0
--analysis-file <filename>
Specify file name used for either dumping or reading analysis data.
--scaling-list <string>
Specify a file containing HM style quant scaling lists or 'default' or 'off'.
Default: off
--lambda-file <string>
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
Loop filters (deblock and SAO):
--[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
VUI options:
--sar <width:height|int>
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
--crop-rect <string>
Add 'left,top,right,bottom' to the bitstream-level cropping rectangle
--overscan <string>
Specify whether it is appropriate for decoder to show cropped region: undef, show
or crop. Default undef
--videoformat <string>
Specify video format from undef, component, pal, ntsc, secam, mac. Default undef
--range <string>
Specify black level and range of luma and chroma signals as full or limited Default
limited
--colorprim <string>
Specify color primaries from undef, bt709, bt470m, bt470bg, smpte170m, smpte240m,
film, bt2020. Default undef
--transfer <string>
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
--colormatrix <string>
Specify color matrix setting from undef, bt709, fcc, bt470bg, smpte170m, smpte240m,
GBR, YCgCo, bt2020nc, bt2020c. Default undef
--chromaloc <integer>
Specify chroma sample location (0 to 5). Default of 0
Bitstream options:
--[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
--hash <integer>
Decoded Picture Hash SEI 0: disabled, 1: MD5, 2: CRC, 3: Checksum. Default 0
Reconstructed video options (debugging):
-r/--recon <filename>
Reconstructed raw image YUV or Y4M output file name
--recon-depth <integer>
Bit-depth of reconstructed raw image file. Defaults to input bit depth, or 8 if Y4M
SEE ALSO
Full documentation may be found at http://x265.readthedocs.org/en/default/cli.html.