kvazaar(1) User Commands kvazaar(1)
NAME
kvazaar - open source HEVC encoder
SYNOPSIS
kvazaar -i <input> --input-res <width>x<height> -o <output>
DESCRIPTION
Required:
-i, --input <filename>
Input file
--input-res <res>
Input resolution [auto]
- auto: Detect from file name.
- <int>x<int>: width times height
-o, --output <filename>
Output file
Presets:
--preset <preset>
Set options to a preset [medium]
- ultrafast, superfast, veryfast, faster,
fast, medium, slow, slower, veryslow
placebo
Input:
-n, --frames <integer>
Number of frames to code [all]
--seek <integer>
First frame to code [0]
--input-fps <num>[/<denom>]
Frame rate of the input video [25]
--source-scan-type <string>
Source scan type [progressive]
- progressive: Progressive scan
- tff: Top field first
- bff: Bottom field first
--input-format <string>
P420 or P400 [P420]
--input-bitdepth <int>
8-16 [8]
--loop-input
Re-read input file forever.
--input-file-format <string>
Input file format [auto]
- auto: Check the file ending for format
- y4m (skips frame headers)
- yuv
Options:
--help Print this help message and exit.
--version
Print version information and exit.
--(no-)aud
Use access unit delimiters. [disabled]
--debug <filename>
Output internal reconstruction.
--(no-)cpuid
Enable runtime CPU optimizations. [enabled]
--hash <string>
Decoded picture hash [checksum]
- none: 0 bytes
- checksum: 18 bytes
- md5: 56 bytes
--(no-)psnr
Calculate PSNR for frames. [enabled]
--(no-)info
Add encoder info SEI. [enabled]
--(no-)enable-logging
Enable logging for regular encoder performance, error messages
are always disblayed. [enabled]
--crypto <string>
Selective encryption. Crypto support must be enabled at
compile-time. Can be 'on' or 'off' or a list of features
separated with a '+'. [off]
- on: Enable all encryption features.
- off: Disable selective encryption.
- mvs: Motion vector magnitudes.
- mv_signs: Motion vector signs.
- trans_coeffs: Coefficient magnitudes.
- trans_coeff_signs: Coefficient signs.
- intra_pred_modes: Intra prediction modes.
--key <string>
Encryption key [16,213,27,56,255,127,242,112,
97,126,197,204,25,59,38,30]
--stats-file-prefix
A prefix used for stats files that include bits, lambda,
distortion, and qp for each ctu. These are meant for debugging
and are not written unless the prefix is defined.
Video structure:
-q, --qp <integer>
Quantization parameter [22]
-p, --period <integer>
Period of intra pictures [64]
- 0: Only first picture is intra.
- 1: All pictures are intra.
- N: Every Nth picture is intra.
--vps-period <integer>
How often the video parameter set is re-sent [0]
- 0: Only send VPS with the first frame.
- N: Send VPS with every Nth intra frame.
-r, --ref <integer>
Number of reference frames, in range 1..15 [4]
--gop <string>
GOP structure [16]
- 0: Disabled
- 8: B-frame pyramid of length 8
- 16: B-frame pyramid of length 16
- lp-<string>: Low-delay P/B-frame GOP
(e.g. lp-g8d4t2, see README)
--intra-qp-offset <int>: QP offset for intra frames [-51..51] [auto]
- N: Set QP offset to N.
- auto: Select offset automatically based
on GOP length.
--(no-)open-gop
Use open GOP configuration. [enabled]
--cqmfile <filename>
Read custom quantization matrices from a file.
--scaling-list <string>: Set scaling list mode. [off]
- off: Disable scaling lists.
- custom: use custom list (with --cqmfile).
- default: Use default lists.
--bitrate <integer>
Target bitrate [0]
- 0: Disable rate control.
- N: Target N bits per second.
--rc-algorithm <string>: Select used rc-algorithm. [lambda]
- lambda: rate control from:
DOI: 10.1109/TIP.2014.2336550
- oba: DOI: 10.1109/TCSVT.2016.2589878
--(no-)intra-bits
Use Hadamard cost based allocation for intra frames. Default on
for gop 8 and off for lp-gop
--(no-)clip-neighbour
On oba based rate control whether to clip lambda values to same
frame's ctus or previous'. Default on for RA GOPS and disabled
for LP.
--(no-)lossless
Use lossless coding. [disabled]
--mv-constraint <string>
Constrain movement vectors. [none]
- none: No constraint
- frametile: Constrain within the tile.
- frametilemargin: Constrain even more.
--roi <filename>
Use a delta QP map for region of interest. Reads an array of
delta QP values from a file. Text and binary files are
supported and detected from the file extension (.txt/.bin). If a
known extension is not found, the file is treated as a text
file. The file can include one or many ROI frames each in the
following format: width and height of the QP delta map followed
by width * height delta QP values in raster order. In binary
format, width and height are 32-bit integers whereas the delta
QP values are signed 8-bit values. The map can be of any size
and will be scaled to the video size. The file reading will loop
if end of the file is reached. See roi.txt in the examples
folder.
--set-qp-in-cu
Set QP at CU level keeping pic_init_qp_minus26. in PPS and
slice_qp_delta in slize header zero.
--(no-)erp-aqp
Use adaptive QP for 360 degree video with equirectangular
projection. [disabled]
--level <number>
Use the given HEVC level in the output and give an error if
level limits are exceeded. [6.2]
- 1, 2, 2.1, 3, 3.1, 4, 4.1, 5, 5.1, 5.2, 6,
6.1, 6.2
--force-level <number>
Same as --level but warnings instead of errors.
--high-tier
Used with --level. Use high tier bitrate limits instead of the
main tier limits during encoding. High tier requires level 4 or
higher.
--(no-)vaq <integer>
Enable variance adaptive quantization with given strength, in
range 1..20. Recommended: 5. [disabled]
Compression tools:
--(no-)deblock <beta:tc>
Deblocking filter. [0:0]
- beta: Between -6 and 6
- tc: Between -6 and 6
--sao <string>
Sample Adaptive Offset [full]
- off: SAO disabled
- band: Band offset only
- edge: Edge offset only
- full: Full SAO
--(no-)rdoq
Rate-distortion optimized quantization [enabled]
--(no-)rdoq-skip
Skip RDOQ for 4x4 blocks. [disabled]
--(no-)signhide
Sign hiding [disabled]
--(no-)smp
Symmetric motion partition [disabled]
--(no-)amp
Asymmetric motion partition [disabled]
--rd <integer>
Mode search complexity [0]
- 0: Skip intra if inter is good enough.
- 1: Rough intra mode search with SATD.
- 2: Refine mode search with SSE.
- 3: More SSE candidates for inter and
chroma mode search for 4x4 intra.
- 4: Even more SSE candidates for both.
- 5: Try all intra modes.
--(no-)mv-rdo
Rate-distortion optimized motion vector costs [disabled]
--(no-)zero-coeff-rdo
If a CU is set inter, check if forcing zero residual improves
the RD cost. [enabled]
--(no-)full-intra-search
Try all intra modes during rough search. [disabled]
--(no-)intra-chroma-search
Test non-derived intra chroma modes.
[disabled]
--(no-)transform-skip
Try transform skip [disabled]
--me <string>
Integer motion estimation algorithm [hexbs]
- hexbs: Hexagon Based Search
- tz: Test Zone Search
- full: Full Search
- full8, full16, full32, full64
- dia: Diamond Search
--me-steps <integer>
Motion estimation search step limit. Only affects 'hexbs' and
'dia'. [-1]
--subme <integer>
Fractional pixel motion estimation level [4]
- 0: Integer motion estimation only
- 1: + 1/2-pixel horizontal and vertical
- 2: + 1/2-pixel diagonal
- 3: + 1/4-pixel horizontal and vertical
- 4: + 1/4-pixel diagonal
--(no-)fast-bipred
Only perform fast bipred search. [enabled]
--pu-depth-inter <int>-<int>
Inter prediction units sizes [0-3]
- 0, 1, 2, 3: from 64x64 to 8x8
- Accepts a list of values separated by ','
for setting separate depths per GOP layer
(values can be omitted to use the first
value for the respective layer).
--pu-depth-intra <int>-<int>
Intra prediction units sizes [1-4]
- 0, 1, 2, 3, 4: from 64x64 to 4x4
- Accepts a list of values separated by ','
for setting separate depths per GOP layer
(values can be omitted to use the first
value for the respective layer).
--ml-pu-depth-intra
Predict the pu-depth-intra using machine
learning trees, overrides the
--pu-depth-intra parameter. [disabled]
--(no-)combine-intra-cus: Whether the encoder tries to code a cu
on lower depth even when search is not
performed on said depth. Should only
be disabled if cus absolutely must not
be larger than limited by the search.
[enabled]
--force-inter
Force the encoder to use inter always. This is mostly for
debugging and is not guaranteed to produce sensible bitstream or
work at all. [disabled]
--tr-depth-intra <int>
Transform split depth for intra blocks [0]
--(no-)bipred
Bi-prediction [enabled]
--cu-split-termination <string>
CU split search termination [zero]
- off: Don't terminate early.
- zero: Terminate when residual is zero.
--me-early-termination <string>
Motion estimation termination [on]
- off: Don't terminate early.
- on: Terminate early.
- sensitive: Terminate even earlier.
--fast-residual-cost <int>
Skip CABAC cost for residual coefficients
when QP is below the limit. [0]
--fast-coeff-table <string>
Read custom weights for residual
coefficients from a file instead of using
defaults [default]
--fast-rd-sampling
Enable learning data sampling for fast coefficient
table generation
--fastrd-accuracy-check
Evaluate the accuracy of fast coefficient
prediction
--fastrd-outdir
Directory to which to output sampled data or accuracy
data, into <fastrd-outdir>/0.txt to
50.txt, one file
for each QP that blocks were estimated
on
--(no-)intra-rdo-et
Check intra modes in rdo stage only until a zero coefficient CU
is found. [disabled]
--(no-)early-skip
Try to find skip cu from merge candidates. Perform no further
search if skip is found. For rd=0..1: Try the first candidate.
For rd=2.. Try the best candidate based
on luma satd cost. [enabled]
--max-merge <integer>
Maximum number of merge candidates, 1..5 [5]
--(no-)implicit-rdpcm
Implicit residual DPCM. Currently only supported with lossless
coding. [disabled]
--(no-)tmvp
Temporal motion vector prediction [enabled]
Parallel processing:
--threads <integer>
Number of threads to use [auto]
- 0: Process everything with main thread.
- N: Use N threads for encoding.
- auto: Select automatically.
--owf <integer>
Frame-level parallelism [auto]
- N: Process N+1 frames at a time.
- auto: Select automatically.
--(no-)wpp
Wavefront parallel processing. [enabled] Enabling tiles
automatically disables WPP. To enable WPP with tiles, re-enable
it after enabling tiles. Enabling wpp with tiles is, however, an
experimental feature since it is not supported in any HEVC
profile.
--tiles <int>x<int>
Split picture into width x height uniform tiles.
--tiles-width-split <string>|u<int>
- <string>: A comma-separated list of tile
column pixel coordinates.
- u<int>: Number of tile columns of uniform
width.
--tiles-height-split <string>|u<int>
- <string>: A comma-separated list of tile
row column pixel coordinates.
- u<int>: Number of tile rows of uniform
height.
--slices <string>
Control how slices are used.
- tiles: Put tiles in independent slices.
- wpp: Put rows in dependent slices.
- tiles+wpp: Do both.
--partial-coding <x-offset>!<y-offset>!<slice-width>!<slice-height>
Encode partial frame. Parts must be merged to form a valid
bitstream. X and Y are CTU offsets. Slice width and height
must be divisible by CTU in pixels unless it is the last CTU
row/column. This parameter is used by kvaShare.
Video Usability Information:
--sar <width:height>
Specify sample aspect ratio
--overscan <string>
Specify crop overscan setting [undef]
- undef, show, crop
--videoformat <string>
Specify video format [undef]
- undef, component, pal, ntsc, secam, mac
--range <string>
Specify color range [tv]
- tv, pc
--colorprim <string>
Specify color primaries [undef]
- undef, bt709, bt470m, bt470bg,
smpte170m, smpte240m, film, bt2020
--transfer <string>
Specify transfer characteristics [undef]
- undef, bt709, bt470m, bt470bg,
smpte170m, smpte240m, linear, log100,
log316, iec61966-2-4, bt1361e,
iec61966-2-1, bt2020-10, bt2020-12
--colormatrix <string>
Specify color matrix setting [undef]
- undef, bt709, fcc, bt470bg, smpte170m,
smpte240m, GBR, YCgCo, bt2020nc, bt2020c
--chromaloc <integer>
Specify chroma sample location (0 to 5) [0]
kvazaar v2.3.2 September 2025 kvazaar(1)
kvazaar 2.3.2 - Generated Sat Sep 20 05:52:56 CDT 2025