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DJXL_NG(1) User Commands DJXL_NG(1)


djxl_ng - djxl_ng


Warning: This is work in progress, consider using djxl instead! djxl_ng: JPEG XL decoder

Flags from ./tools/

-allow_more_progressive_steps (allow decoding more progressive steps in

truncated files. No effect without --allow_partial_files) type: bool default: false

-allow_partial_files (allow decoding of truncated files) type: bool

default: false

-bits_per_sample (0 = original (input) bit depth) type: int32 default: 0

-color_space (defaults to original (input) color space) type: string

default: "RGB_D65_SRG_Rel_Lin"

-display_nits (luminance range of the display to which to tone-map; the

lower bound can be omitted) type: string default: "0.f-255."

-downsampling (maximum permissible downsampling factor (values greater than

16 will return the LQIP if available) type: uint32 default: 0

-jpeg_quality (JPEG output quality. Setting an output quality implies

--pixels_to_jpeg.) type: uint32 default: 95

-num_reps (How many times to decompress.) type: int64 default: 1

-num_threads (Number of worker threads (0 == use machine default).)

type: int64 default: 0

-pixels_to_jpeg (By default, if the input JPEG XL contains a recompressed

JPEG file, djxl reconstructs the exact original JPEG file. This flag causes the decoder to instead decode the image to pixels and encode a new (lossy) JPEG. The output file if provided must be a .jpg or .jpeg file.) type: bool default: false

-preserve_saturation (with --tone_map, how much to favor saturation over

luminance) type: double default: 0.10000000000000001

-print_read_bytes (print total number of decoded bytes) type: bool

default: false

-quiet (silence output (except for errors)) type: bool default: false

-tone_map (tone map the image to the luminance range indicated by

--display_nits instead of performing a naive 0-1 -> 0-1 conversion)

type: bool default: true


This manual page was written by Mathieu Malaterre <> for the Debian GNU/Linux system (but may be used by others).

April 2022 djxl_ng 0.7.0