Add support for JPEG XL (#242)

Author: NathanMOlson

Makefile

@@ -20,7 +20,7 @@ endif
 EXIF_PY := $(if $(shell which EXIF.py),EXIF.py,./EXIF.py)
 
 # Find images, support multiple case insensitive extensions and file names with spaces
-FIND_IMAGES := find tests/resources -regextype posix-egrep -iregex ".*\.(bmp|gif|heic|heif|jpg|jpeg|png|tiff|webp|arw|avif)" -print0 | LC_COLLATE=C sort -fz | xargs -0
+FIND_IMAGES := find tests/resources -regextype posix-egrep -iregex ".*\.(bmp|gif|heic|heif|jpg|jpeg|png|tiff|webp|arw|avif|jxl)" -print0 | LC_COLLATE=C sort -fz | xargs -0
 
 
 .PHONY: help

README.rst

@@ -24,7 +24,7 @@ Easy to use Python module to extract Exif metadata from digital image files.
 
 Pure Python, lightweight, no dependencies.
 
-Supported formats: TIFF, JPEG, PNG, Webp, HEIC
+Supported formats: TIFF, JPEG, PNG, Webp, HEIC, JPEG XL
 
 
 Compatibility

exifread/core/find_exif.py

@@ -6,6 +6,7 @@
 from exifread.core.exceptions import ExifNotFound, InvalidExif
 from exifread.core.heic import HEICExifFinder, find_heic_tiff
 from exifread.core.jpeg import find_jpeg_exif
+from exifread.core.jxl import JXLExifFinder
 from exifread.core.utils import ord_
 from exifread.exif_log import get_logger
 
@@ -76,6 +77,18 @@ def find_png_exif(fh: BinaryIO, data: bytes) -> Tuple[int, bytes]:
     raise ExifNotFound("PNG file does not have exif data.")
 
 
+def find_jxl_exif(fh: BinaryIO) -> Tuple[int, bytes]:
+    logger.debug("JPEG XL format recognized in data[0:12]")
+
+    fh.seek(0)
+    jxl = JXLExifFinder(fh)
+    offset, endian = jxl.find_exif()
+    if offset > 0:
+        return offset, endian
+
+    raise ExifNotFound("JPEG XL file does not have exif data.")
+
+
 def determine_type(fh: BinaryIO) -> Tuple[int, bytes, int]:
     # by default do not fake an EXIF beginning
     fake_exif = 0
@@ -98,6 +111,8 @@ def determine_type(fh: BinaryIO) -> Tuple[int, bytes, int]:
         offset, endian, fake_exif = find_jpeg_exif(fh, data, fake_exif)
     elif data[0:8] == b"\x89PNG\r\n\x1a\n":
         offset, endian = find_png_exif(fh, data)
+    elif data == b"\0\0\0\x0cJXL\x20\x0d\x0a\x87\x0a":
+        offset, endian = find_jxl_exif(fh)
     else:
         raise ExifNotFound("File format not recognized.")
     return offset, endian, fake_exif

exifread/core/jxl.py

@@ -0,0 +1,23 @@
+"""
+Find Exif data in a JPEG XL file
+"""
+
+from typing import Tuple
+
+from exifread.core.heic import HEICExifFinder
+
+
+class JXLExifFinder(HEICExifFinder):
+    """Find JPEG XL EXIF tags."""
+
+    def find_exif(self) -> Tuple[int, bytes]:
+        ftyp = self.expect_parse("ftyp")
+        assert ftyp.major_brand == b"jxl "
+        assert ftyp.minor_version == 0
+        exif = self.expect_parse("Exif")
+
+        offset = exif.pos + 4
+        self.file_handle.seek(offset - 8)
+        assert self.get(8)[:6] == b"Exif\x00\x00"
+        endian = self.file_handle.read(1)
+        return offset, endian

tests/resources/dump.txt

@@ -5092,6 +5092,33 @@ Thumbnail YResolution (Ratio): 72
 Opening: tests/resources/jpg/xmp/no_exif.jpg
 No EXIF information found
 
+Opening: tests/resources/jxl/test_0001.jxl
+EXIF DateTimeOriginal (ASCII): 2025:08:15 22:25:54
+EXIF FocalLength (Ratio): 14
+EXIF FocalPlaneResolutionUnit (Short): 3
+EXIF FocalPlaneXResolution (Ratio): 3/2500
+EXIF FocalPlaneYResolution (Ratio): 3/2500
+EXIF Make (ASCII): Lab 308
+EXIF MakerNote (ASCII): {}
+EXIF Model (ASCII): Smart Pilot Cam
+EXIF TimeZoneOffset (Signed Short): 0
+GPS GPSAltitude (Ratio): 2019847/1000
+GPS GPSAltitudeRef (Byte): 0
+GPS GPSImgDirection (Ratio): 124223909/1000000
+GPS GPSImgDirectionRef (ASCII): T
+GPS GPSLatitude (Ratio): [525660803/11930465, 0, 0]
+GPS GPSLatitudeRef (ASCII): N
+GPS GPSLongitude (Ratio): [1447334054/11930465, 0, 0]
+GPS GPSLongitudeRef (ASCII): W
+GPS GPSSpeed (Ratio): 50399963/200000
+GPS GPSSpeedRef (ASCII): K
+GPS GPSTrack (Ratio): 34223909/1000000
+GPS GPSTrackRef (ASCII): T
+GPS Tag 0xD000 (Signed Ratio): 40
+GPS Tag 0xD001 (Signed Ratio): 0
+Image ExifOffset (Long): 38
+Image GPSInfo (Long): 220
+
 Opening: tests/resources/raw/sony_alpha_a7iii_raw_image.ARW
 EXIF BrightnessValue (Signed Ratio): -3483/1280
 EXIF ColorSpace (Short): sRGB