Pure python jpeg reader.
Developed with Python 3.8, but should be compatible with Python 3.6+.
This will get resolution, pixel aspect ratio, and some metadata from most JPEG files. Additionally, byte offsets to known segment markers are stored.
While JPEG files conform to a standard, there are a vast number of application-specific formats for image metadata and thumbnails. Therefore, this module won't read all metadata from each and every type of JPEG. That's a rabbit hole I don't care to go down.
jpeg_reader can be imported and used as a module to extract information from a JPEG file.
# Example: Print file info
from jpeg_reader import JpegFile
jf = JpegFile("test_image.jpg")
print(jf.resolution)
print(jf.pixel_aspect)
for key, value in jf.metadata.items():
print(key, value)# Example: Read SOS (Start of Scan) data
from jpeg_reader import JpegFile
from jpeg_reader import ReadSegment
from jpeg_reader import segment_markers
jf = JpegFile("test_image.jpg")
for segment in jf.segments:
marker = segment.marker
if segment.marker == segment_markers.SOS:
sos_segment = segment
break
with open("test_image.jpg", 'rb') as f:
with ReadSegment(file=f, segment_start=sos_segment.offset) as seg:
seg.go_to_segment_data()
# Do whatever you need to here
passjpeg_reader.py can also be used from the command line to print information about an individual file, or a directory containing multiple images.
jpeg_reader.py test_image.jpg
jpeg_reader.py C:\path\to\images
These are links that I found useful for reference.
JPEG:
- Specs: https://www.w3.org/Graphics/JPEG/itu-t81.pdf
- https://en.wikipedia.org/wiki/JPEG#Syntax_and_structure
APP Segments:
JFIF:
- Specs: http://www.ecma-international.org/publications/files/ECMA-TR/ECMA%20TR-098.pdf
- http://vip.sugovica.hu/Sardi/kepnezo/JPEG%20File%20Layout%20and%20Format.htm
- https://en.wikipedia.org/wiki/JPEG_File_Interchange_Format#File_format_structure
EXIF: