x265参数详解（基于版本2.8）
Syntax: x265 [options] infile [-o] outfile
infile can be YUV or Y4M
outfile is raw HEVC bitstream
Executable Options:
-h/--help Show this help text and exit
--fullhelp Show all options and exit
-V/--version Show version info and exit
Output Options:
-o/--output <filename> Bitstream output file name
-D/--output-depth 8|10|12 Output bit depth (also internal bit depth). Default 8
--log-level <string> Logging level: none error warning info debug full. Default full
--no-progress Disable CLI progress reports
--csv <filename> Comma separated log file, if csv-log-level > 0 frame level statistics, else one line per run
--csv-log-level <integer> Level of csv logging, if csv-log-level > 0 frame level statistics, else one line per run: 0-2
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> Chroma subsampling, auto-detected if Y4M
0 - i400 (4:0:0 monochrome)
1 - i420 (4:2:0 default)
2 - i422 (4:2:2)
3 - i444 (4:4:4)
-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
--[no-]copy-pic Copy buffers of input picture in frame. Default enabled
Quality reporting metrics:
--[no-]ssim Enable reporting SSIM metric scores. Default disabled
--[no-]psnr Enable reporting PSNR metric scores. Default disabled
Profile, Level, Tier:
-P/--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
--uhd-bd Enable UHD Bluray compatibility support
--[no-]allow-non-conformance Allow the encoder to generate profile NONE bitstreams. Default disabled
Threading, performance:
--pools <integer,...> Comma separated thread count per thread pool (pool per NUMA node)
'-' implies no threads on node, '+' implies one thread per core on node
-F/--frame-threads <integer> Number of concurrently encoded frames. 0: auto-determined by core count
--[no-]wpp Enable Wavefront Parallel Processing. Default enabled
--[no-]slices <integer> Enable Multiple Slices feature. Default 1
--[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, grain, zerolatency, fastdecode
Quad-Tree size and depth:
-s/--ctu <64|32|16> Maximum CU size (WxH). Default 64
--min-cu-size <64|32|16|8> Minimum CU size (WxH). Default 8
--max-tu-size <32|16|8|4> Maximum TU size (WxH). Default 32
--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
--limit-tu <0..4> Enable early exit from TU recursion for inter coded blocks. Default 0
Analysis:
--rd <1..6> Level of RDO in mode decision 1:least....6:full RDO. Default 3
--[no-]psy-rd <0..5.0> Strength of psycho-visual rate distortion optimization, 0 to disable. Default 2.0
--[no-]rdoq-level <0|1|2> Level of RDO in quantization 0:none, 1:levels, 2:levels & coding groups. Default 0
--[no-]psy-rdoq <0..50.0> Strength of psycho-visual optimization in RDO quantization, 0 to disable. Default 0.0
--dynamic-rd <0..4.0> Strength of dynamic RD, 0 to disable. Default 0.00
--[no-]ssim-rd Enable ssim rate distortion optimization, 0 to disable. Default disabled
--[no-]rd-refine Enable QP based RD refinement for rd levels 5 and 6. Default disabled
--[no-]early-skip Enable early SKIP detection. Default disabled
--[no-]rskip Enable early exit from recursion. Default enabled
--[no-]tskip-fast Enable fast intra transform skipping. Default disabled
--[no-]splitrd-skip Enable skipping split RD analysis when sum of split CU rdCost larger than none split CU rdCost for Intra CU. Default disabled
--nr-intra <integer> An integer value in range of 0 to 2000, which denotes strength of noise reduction in intra CUs. Default 0
--nr-inter <integer> An integer value in range of 0 to 2000, which denotes strength of noise reduction in inter CUs. Default 0
--ctu-info <integer> Enable receiving ctu information asynchronously and determine reaction to the CTU information (0, 1, 2, 4, 6) Default 0
- 1: force the partitions if CTU information is present
- 2: functionality of (1) and reduce qp if CTU information has changed
- 4: functionality of (1) and force Inter modes when CTU Information has changed, merge/skip otherwise
Enable this option only when planning to invoke the API function x265_encoder_ctu_info to copy ctu-info asynchronously
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:
--max-merge <1..5> Maximum number of merge candidates. Default 2
--ref <integer> max number of L0 references to be allowed (1 .. 16) Default 3
--limit-refs <0|1|2|3> Limit references per depth (1) or CU (2) or both (3). Default 3
--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
--[no-]rect Enable rectangular motion partitions Nx2N and 2NxN. Default disabled
--[no-]amp Enable asymmetric motion partitions, requires --rect. Default disabled
--[no-]limit-modes Limit rectangular and asymmetric motion predictions. Default 0
--[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
--gop-lookahead <integer> Extends gop boundary if a scenecut is found within this from keyint boundary. Default 0
--no-scenecut Disable adaptive I-frame decision
--scenecut <integer> How aggressively to insert extra I-frames. Default 40
--scenecut-bias <0..100.0> Bias for scenecut detection. Default 5.00
--radl <integer> Number of RADL pictures allowed in front of IDR. Default 0
--intra-refresh Use Periodic Intra Refresh instead of IDR frames
--rc-lookahead <integer> Number of frames for frame-type lookahead (determines encoder latency) Default 20
--lookahead-slices <0..16> Number of slices to use per lookahead cost estimate. Default 8
--lookahead-threads <integer> Number of threads to be dedicated to perform lookahead only. Default 0
-b/--bframes <0..16> Maximum number of consecutive b-frames. 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
--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,K,P,B,b.
QPs are restricted by qpmin/qpmax.
--force-flush <integer> Force the encoder to flush frames. Default 0
0 - flush the encoder only when all the input pictures are over.
1 - flush all the frames even when the input is not over. Slicetype decision may change with this option.
2 - flush the slicetype decided frames only.
Rate control, Adaptive 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 28.0
--[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 0.90
--vbv-end <float> Final VBV buffer emptiness (fraction of bufsize or in kbits). Default 0 (disabled)
--vbv-end-fr-adj <float> Frame from which qp has to be adjusted to achieve final decode buffer emptiness. Default 0
--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-]multi-pass-opt-analysis Refine analysis in 2 pass based on analysis information from pass 1
--[no-]multi-pass-opt-distortion Use distortion of CTU from pass 1 to refine qp in 2 pass
--stats Filename for stats file in multipass pass rate control. Default x265_2pass.log
--[no-]analyze-src-pics Motion estimation uses source frame planes. Default disable
--[no-]slow-firstpass Enable a slow first pass in a multipass rate control mode. Default enabled
--[no-]strict-cbr Enable stricter conditions and tolerance for bitrate deviations in CBR mode. Default disabled
--analysis-save <filename> Dump analysis info into the specified file. Default Disabled
--analysis-load <filename> Load analysis buffers from the file specified. Default Disabled
--analysis-reuse-file <filename> Specify file name used for either dumping or reading analysis data. Deault x265_analysis.dat
--analysis-reuse-level <1..10> Level of analysis reuse indicates amount of info stored/reused in save/load mode, 1:least..10:most. Default 5
--refine-mv-type <string> Reuse MV information received through API call. Supported option is avc. Default disabled - 0
--scale-factor <int> Specify factor by which input video is scaled down for analysis save mode. Default 0
--refine-intra <0..4> Enable intra refinement for encode that uses analysis-load.
- 0 : Forces both mode and depth from the save encode.
- 1 : Functionality of (0) + evaluate all intra modes at min-cu-size's depth when current depth is one smaller than min-cu-size's depth.
- 2 : Functionality of (1) + irrespective of size evaluate all angular modes when the save encode decides the best mode as angular.
- 3 : Functionality of (1) + irrespective of size evaluate all intra modes.
- 4 : Re-evaluate all intra blocks, does not reuse data from save encode.
Default:0
--refine-inter <0..3> Enable inter refinement for encode that uses analysis-load.
- 0 : Forces both mode and depth from the save encode.
- 1 : Functionality of (0) + evaluate all inter modes at min-cu-size's depth when current depth is one smaller than
min-cu-size's depth. When save encode decides the current block as skip(for all sizes) evaluate skip/merge.
- 2 : Functionality of (1) + irrespective of size restrict the modes evaluated when specific modes are decided as the best mode by the save encode.
- 3 : Functionality of (1) + irrespective of size evaluate all inter modes.
Default:0
--[no-]dynamic-refine Dynamically changes refine-inter level for each CU. Default disabled
--[no-]refine-mv Enable mv refinement for load mode. Default disabled
--aq-mode <integer> Mode for Adaptive Quantization - 0:none 1:uniform AQ 2:auto variance 3:auto variance with bias to dark scenes. Default 1
--aq-strength <float> Reduces blocking and blurring in flat and textured areas (0 to 3.0). Default 1.00
--[no-]aq-motion Adaptive Quantization based on the relative motion of each CU w.r.t., frame. Default disabled
--qg-size <int> Specifies the size of the quantization group (64, 32, 16, 8). Default 32
--[no-]cutree Enable cutree for Adaptive Quantization. Default enabled
--[no-]rc-grain Enable ratecontrol mode to handle grains specifically. turned on with tune grain. Default disabled
--ipratio <float> QP factor between I and P. Default 1.40
--pbratio <float> QP factor between P and B. Default 1.30
--qcomp <float> Weight given to predicted complexity. Default 0.60
--qpstep <integer> The maximum single adjustment in QP allowed to rate control. Default 4
--qpmin <integer> sets a hard lower limit on QP allowed to ratecontrol. Default 0
--qpmax <integer> sets a hard upper limit on QP allowed to ratecontrol. Default 69
--[no-]const-vbv Enable consistent vbv. turned on with tune grain. Default disabled
--cbqpoffs <integer> Chroma Cb QP Offset [-12..12]. Default 0
--crqpoffs <integer> Chroma Cr QP Offset [-12..12]. Default 0
--scaling-list <string> Specify a file containing HM style quant scaling lists or 'default' or 'off'. Default: off
--zones <zone0>/<zone1>/... Tweak the bitrate of regions of the video
Each zone is of the form
<start frame>,<end frame>,<option>
where <option> is either
q=<integer> (force QP)
or b=<float> (bitrate multiplier)
--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
--max-ausize-factor <float> This value controls the maximum AU size defined in specification.
It represents the percentage of maximum AU size used. Default 1.0
Loop filters (deblock and SAO):
--[no-]deblock Enable Deblocking Loop Filter, optionally specify tC:Beta offsets 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
--[no-]limit-sao Limit Sample Adaptive Offset types. 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
--display-window <string> Describe overscan cropping region as 'left,top,right,bottom' in pixels
--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 bt709, unknown, reserved, bt470m, bt470bg, smpte170m,
smpte240m, film, bt2020, smpte428, smpte431, smpte432. Default undef
--transfer <string> Specify transfer characteristics from bt709, unknown, reserved, bt470m, bt470bg, smpte170m,
smpte240m, linear, log100, log316, iec61966-2-4, bt1361e, iec61966-2-1,
bt2020-10, bt2020-12, smpte2084, smpte428, arib-std-b67. Default undef
--colormatrix <string> Specify color matrix setting from undef, bt709, fcc, bt470bg, smpte170m,
smpte240m, GBR, YCgCo, bt2020nc, bt2020c, smpte2085, chroma-derived-nc, chroma-derived-c, ictcp. Default undef
--chromaloc <integer> Specify chroma sample location (0 to 5). Default of 0
--master-display <string> SMPTE ST 2086 master display color volume info SEI (HDR)
format: G(x,y)B(x,y)R(x,y)WP(x,y)L(max,min)
--max-cll <string> Emit content light level info SEI as "cll,fall" (HDR)
--[no-]hdr Control dumping of HDR SEI packet. If max-cll or master-display has non-zero values, this is enabled. Default disabled
--[no-]hdr-opt Add luma and chroma offsets for HDR/WCG content. Default disabled
--min-luma <integer> Minimum luma plane value of input source picture
--max-luma <integer> Maximum luma plane value of input source picture
Bitstream options:
--[no-]repeat-headers Emit SPS and PPS headers at each keyframe. Default disabled
--[no-]info Emit SEI identifying encoder and parameters. Default enabled
--[no-]hrd Enable HRD parameters signaling. Default disabled
--[no-]idr-recovery-sei Emit recovery point infor SEI at each IDR frame
--[no-]temporal-layers Enable a temporal sublayer for unreferenced B frames. Default disabled
--[no-]aud Emit access unit delimiters at the start of each access unit. Default disabled
--hash <integer> Decoded Picture Hash SEI 0: disabled, 1: MD5, 2: CRC, 3: Checksum. Default 0
--atc-sei <integer> Emit the alternative transfer characteristics SEI message where the integer is the preferred transfer characteristics. Default disabled
--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.
--log2-max-poc-lsb <integer> Maximum of the picture order count
--[no-]vui-timing-info Emit VUI timing information in the bistream. Default enabled
--[no-]vui-hrd-info Emit VUI HRD information in the bistream. Default enabled
--[no-]opt-qp-pps Dynamically optimize QP in PPS (instead of default 26) based on QPs in previous GOP. Default disabled
--[no-]opt-ref-list-length-pps Dynamically set L0 and L1 ref list length in PPS (instead of default 0) based on values in last GOP. Default disabled
--[no-]multi-pass-opt-rps Enable storing commonly used RPS in SPS in multi pass mode. Default disabled
--[no-]opt-cu-delta-qp Optimize to signal consistent CU level delta QPs in frame. Default disabled
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
--recon-y4m-exec <string> pipe reconstructed frames to Y4M viewer, ex:"ffplay -i pipe:0 -autoexit"
--lowpass-dct Use low-pass subband dct approximation. Default disabled
Executable return codes:
0 - encode successful
1 - unable to parse command line
2 - unable to open encoder
3 - unable to generate stream headers
4 - encoder abort
Complete documentation may be found at http://x265.readthedocs.org/en/default/cli.html