OPTIONS¶
--container=0|1
0 = Do not encode using container format (strip
Exif/XMP/JPEG bitstream reconstruction data).1 = Force using container format
(default: use only if needed).
--jpeg_store_metadata=0|1
If --lossless_jpeg=1, store JPEG reconstruction metadata
in the JPEG XL container (for lossless reconstruction of the JPEG
codestream).(default: 1)
-d distance, --distance=distance
Max. butteraugli distance, lower = higher quality. 0.0 =
mathematically lossless. Default for already-lossy input (JPEG/GIF). 1.0 =
visually lossless. Default for other input. Recommended range: 0.5 .. 3.0.
Mutually exclusive with --quality.
-q quality, --quality=quality
Quality setting (is remapped to --distance). Range: -inf
.. 100. 100 = mathematically lossless. Default for already-lossy input
(JPEG/GIF). Other input gets encoded as per --distance default. Positive
quality values roughly match libjpeg quality. Mutually exclusive with
--distance.
-e effort, --effort=effort
Encoder effort setting. Range: 1 .. 9. Default: 7. Higher
number is more effort (slower).
Recognized effort settings, from fastest to slowest, are:
•1 or “lightning”
•2 or “thunder”
•3 or “falcon”
•4 or “cheetah”
•5 or “hare”
•6 or “wombat”
•7 or “squirrel” (default)
•8 or “kitten”
•9 or “tortoise”
--brotli_effort=B_EFFORT
Brotli effort setting. Range: 0 .. 11. Default: 9. Higher
number is more effort (slower).
--faster_decoding=0|1|2|3|4
Favour higher decoding speed. 0 = default, higher values
give higher speed at the expense of quality
-p, --progressive
Enable progressive/responsive decoding.
--premultiply=-1|0|1
Force premultiplied (associated) alpha.
--keep_invisible=0|1
Force disable/enable preserving color of invisible pixels
(default: 1 if lossless, 0 if lossy).
--group_order=0|1
Order in which 256x256 groups are stored in the
codestream for progressive rendering. Value not provided means encoder
default, 0 means scanline order, 1 means center-first
order.
--center_x=0..XSIZE
Determines the horizontal position of center for the
center-first group order. The value -1 means use the middle of the
image, other values [0..xsize) set this to a particular coordinate.
--center_y=0..YSIZE
Determines the vertical position of center for the
center-first group order. The value -1 means use the middle of the
image, other values [0..ysize) set this to a particular coordinate.
--progressive_ac
Use the progressive mode for AC.
--qprogressive_ac
Use the progressive mode for AC with shift
quantization.
--progressive_dc=num_dc_frames
Progressive-DC setting. Valid values are: -1, 0, 1,
2.
-m=0|1, --modular=0|1
Use modular mode (not provided = encoder chooses, 0 =
enforce VarDCT, 1 = enforce modular mode).
-j=0|1, --lossless_jpeg=0|1
If the input is JPEG, losslessly transcode JPEG, rather
than using reencode pixels.
--jpeg_reconstruction_cfl=0|1
Enable/disable chroma-from-luma (CFL) for lossless JPEG
reconstruction.
--num_threads=N
Number of worker threads (-1 == use machine default, 0 ==
do not use multithreading).
--num_reps=N
How many times to compress. (For benchmarking).
--photon_noise=ISO3200
Adds noise to the image emulating photographic film
noise. The higher the given number, the grainier the image will be. As an
example, a value of 100 gives low noise whereas a value of 3200 gives a lot of
noise. The default value is 0.
--dots=0|1
Force disable/enable dots generation. (not provided =
default, 0 = disable, 1 = enable).
--patches=0|1
Force disable/enable patches generation. (not provided =
default, 0 = disable, 1 = enable).
--resampling=-1|1|2|4|8
Resampling for extra channels. Default of -1 applies
resampling only for low quality. Value 1 does no downsampling (1x1), 2 does
2x2 downsampling, 4 is for 4x4 downsampling, and 8 for 8x8 downsampling.
--ec_resampling=1|2|4|8
Resampling for extra channels. Default of -1 applies
resampling only for low quality. Value 1 does no downsampling (1x1), 2 does
2x2 downsampling, 4 is for 4x4 downsampling, and 8 for 8x8 downsampling.
--already_downsampled
Do not downsample the given input before encoding, but
still signal that the decoder should upsample.
--epf=-1|0|1|2|3
Edge preserving filter level, -1 to 3. Value -1 means:
default (encoder chooses), 0 to 3 set a strength.
--gaborish=0|1
Force disable/enable the gaborish filter. (not provided =
default, 0 = disable, 1 = enable).
--intensity_target=N
Upper bound on the intensity level present in the image
in nits. Leaving this set to its default of 0 lets libjxl choose a sensible
default value based on the color encoding.
-x=key=value, --dec-hints=key=value
color_space indicates the ColorEncoding, see
Description(); icc_pathname refers to a binary file containing an ICC
profile.
--override_bitdepth=0=use from image, 1-32=override If nonzero,
store the given bit depth in the JPEG XL file metadata (1-32), instead of
using the bit depth from the original input image.
-I F, --iterations=F
[modular encoding] Fraction of pixels used to learn MA
trees as a percentage. -1 = default, 0 = no MA and fast decode, 50 = default
value, 100 = all.Higher values use more encoder memory.
-C K, --modular_colorspace=K
[modular encoding] color transform: -1=default, 0=RGB
(none), 1-41=RCT (6=YCoCg, default: try several, depending on speed)
-g K, --modular_group_size=K
[modular encoding] group size: -1 == default. 0 ⇒
128, 1 ⇒ 256, 2 ⇒ 512, 3 ⇒ 1024
-P K, --modular_predictor=K
[modular encoding] predictor(s) to use:
•0=zero,
•1=left,
•2=top,
•3=avg0,
•4=select,
•5=gradient,
•6=weighted,
•7=topright,
•8=topleft,
•9=leftleft,
•10=avg1,
•11=avg2,
•12=avg3,
•13=toptop predictive average
•14=mix 5 and 6,
•15=mix everything.
Default 14, at slowest speed default 15
-E K, --modular_nb_prev_channels=K
[modular encoding] number of extra MA tree properties to
use
--modular_palette_colors=K
[modular encoding] Use color palette if number of colors
is smaller than or equal to this, or -1 to use the encoder default.
--modular_lossy_palette
[modular encoding] quantize to a palette that has fewer
entries than would be necessary for perfect preservation; for the time being,
it is recommended to set --palette=0 with this option to use the default
palette only
-X PERCENT, --pre-compact=PERCENT
[modular encoding] Use Global channel palette if the
number of colors is smaller than this percentage of range. Use 0-100 to set an
explicit percentage, -1 to use the encoder default.
-Y PERCENT, --post-compact=PERCENT
[modular encoding] Use Local (per-group) channel palette
if the number of colors is smaller than this percentage of range. Use 0-100 to
set an explicit percentage, -1 to use the encoder default.
--codestream_level=K
The codestream level. Either -1, 5 or 10.
-R K, --responsive=K
[modular encoding] do Squeeze transform, 0=false, 1=true
(default: true if lossy, false if lossless)
-V --version:: Print encoder library version number and exit.
--quiet
Be more silent
--frame_indexing=string
If non-empty, a string matching ^(0*|1[01]*). If
this string has a 1 in i-th position, then the i-th frame will be
indexed in the frame index box.
-v, --verbose
Increases verbosity. Can be repeated to increase it
further, and also applies to --help.
-h, --help
Displays the options that cjxl supports. On its own, it
will only show basic options. It can be combined with -v or -v -v to show
increasingly advanced options as well.
