--- name: "x265" section: "1" platform: "linux" package: "x265" version: "4.1-2" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/x265" --- # x265(1) encoder for creating H.265/HEVC video streams ## 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 \ Bitstream output file name - **--log-level** \ 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** \ Comma separated log file, log level \>= 3 frame log, else one line per run ### Input Options: - **--input** \ Raw YUV or Y4M input file name. \`-\` for stdin - **--y4m** Force parsing of input stream as YUV4MPEG2 regardless of file extension - **--fps** \ 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** \ Bit-depth of input file. Default 8 - **--input-csp** \ Source color space: i420, i444 or i422, auto-detected if Y4M. Default: i420 - **-f**/--frames \ Maximum number of frames to encode. Default all - **--seek** \ First frame to encode - **--\[no-\]interlace** \ 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** \ Enforce an encode profile: main, main10, mainstillpicture - **--level-idc** \ 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** \ Number of threads for thread pool (0: detect CPU core count, default) - **-F**/--frame-threads \ 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** \ Override CPU detection. Default: auto ### Presets: - **-p**/--preset \ Trade off performance for compression efficiency. Default medium - ultrafast, superfast, veryfast, faster, fast, medium, slow, slower, veryslow, or placebo - **-t**/--tune \ 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** \ Max TU recursive depth for intra CUs. Default 1 - **--tu-inter-depth** \ 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** \ 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** \ Motion search method dia hex umh star full. Default 1 - **-m**/--subme \ Amount of subpel refinement to perform (0:least .. 7:most). Default 2 - **--merange** \ 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 \ Max IDR period in frames. **-1** for infinite-gop. Default 250 - **-i**/--min-keyint \ Scenecuts closer together than this are coded as I, not IDR. Default: auto - **--no-scenecut** Disable adaptive I-frame decision - **--scenecut** \ How aggressively to insert extra I-frames. Default 40 - **--rc-lookahead** \ Number of frames for frame-type lookahead (determines encoder latency) Default 20 - **--bframes** \ Maximum number of consecutive b-frames (now it only enables B GOP structure) Default 4 - **--bframe-bias** \ 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** \ max number of L0 references to be allowed (1 .. 16) Default 3 - **--qpfile** \ 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** \ Target bitrate (kbps) for ABR (implied). Default 0 - **-q**/--qp \ QP for P slices in CQP mode (implied). **--ipratio** and **--pbration** determine other slice QPs - **--crf** \ Quality-based VBR (0-51). Default 28.000000 - **--\[no-\]lossless** Enable lossless: bypass transform, quant and loop filters globally. Default disabled - **--crf-max** \ With CRF+VBV, limit RF to this value. Default 0.000000 May cause VBV underflows! - **--crf-min** \ With CRF+VBV, limit RF to this value. Default 0.000000 this specifies a minimum rate factor value for encode! - **--vbv-maxrate** \ Max local bitrate (kbit/s). Default 0 - **--vbv-bufsize** \ Set size of the VBV buffer (kbit). Default 0 - **--vbv-init** \ Initial VBV buffer occupancy (fraction of bufsize or in kbits). Default 0.900000 - **--aq-mode** \ Mode for Adaptive Quantization - 0:none 1:uniform AQ 2:auto variance. Default 2 - **--aq-strength** \ 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** \ QP factor between I and P. Default 1.400000 - **--pbratio** \ QP factor between P and B. Default 1.300000 - **--cbqpoffs** \ Chroma Cb QP Offset. Default 0 - **--crqpoffs** \ 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** \ save - Dump analysis info into file, load - Load analysis buffers from the file. Default 0 - **--analysis-file** \ Specify file name used for either dumping or reading analysis data. - **--scaling-list** \ Specify a file containing HM style quant scaling lists or 'default' or 'off'. Default: off - **--lambda-file** \ 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** \ 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 \. Default 0 - **--crop-rect** \ Add 'left,top,right,bottom' to the bitstream-level cropping rectangle - **--overscan** \ Specify whether it is appropriate for decoder to show cropped region: undef, show or crop. Default undef - **--videoformat** \ Specify video format from undef, component, pal, ntsc, secam, mac. Default undef - **--range** \ Specify black level and range of luma and chroma signals as full or limited Default limited - **--colorprim** \ Specify color primaries from undef, bt709, bt470m, bt470bg, smpte170m, smpte240m, film, bt2020. Default undef - **--transfer** \ 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** \ Specify color matrix setting from undef, bt709, fcc, bt470bg, smpte170m, smpte240m, GBR, YCgCo, bt2020nc, bt2020c. Default undef - **--chromaloc** \ 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** \ Decoded Picture Hash SEI 0: disabled, 1: MD5, 2: CRC, 3: Checksum. Default 0 ### Reconstructed video options (debugging): - **-r**/--recon \ Reconstructed raw image YUV or Y4M output file name - **--recon-depth** \ 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.