exiftool *Warning* *Invalid EXIF text encoding for UserComment* if specify more than 8 characters #6

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Benjamin_Loison · 2025-11-20T16:50:58+01:00

Benjamin_Loison commented

2025-11-20 16:50:58 +01:00

See Benjamin_Loison/firefox/issues/200#issuecomment-8375424.

Searching upstream open and closed issues and pull requests for "Invalid EXIF text encoding for" does not return anything.

Related to #5.

See [Benjamin_Loison/firefox/issues/200#issuecomment-8375424](https://codeberg.org/Benjamin_Loison/firefox/issues/200#issuecomment-8375424). Searching upstream open and closed issues and pull requests for `"Invalid EXIF text encoding for"` does not return anything. Related to #5.

Benjamin_Loison commented

2025-12-26 17:51:51 +01:00

DuckDuckGo and Google search "Invalid EXIF text encoding for" and "Invalid EXIF text encoding for" "8".

Note that whole UserComment is still retrievable with exiftool.

DuckDuckGo and Google search `"Invalid EXIF text encoding for"` and `"Invalid EXIF text encoding for" "8"`. Note that whole *UserComment* is still retrievable with `exiftool`.

Benjamin_Loison commented

2025-12-26 21:13:41 +01:00

Error:

Traceback (most recent call last):
  File "<tmp 1>", line 6, in <module>
    exif[0x9286] = ('a' * 8).encode('unicode')
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^
LookupError: unknown encoding: unicode

<details> <summary>Error:</summary> ``` Traceback (most recent call last): File "<tmp 1>", line 6, in <module> exif[0x9286] = ('a' * 8).encode('unicode') ^^^^^^^^^^^^^^^^^^^^^^^^^^^ LookupError: unknown encoding: unicode ``` </details>

Benjamin_Loison commented

2025-12-26 21:18:36 +01:00

DuckDuckGo and Google search "LookupError: unknown encoding: unicode".

DuckDuckGo search Python unicode string.

https://docs.python.org/3/howto/unicode.html

exif[0x9286] = ('a' * 8).encode()

results in the warning.

python-pillow/Pillow/issues/5254

DuckDuckGo and Google search JIS.

Wikipedia: JIS (1187947658)

Python script:

from PIL import Image

imageCropped = Image.new('RGB', (100, 100))

exif = imageCropped.getexif()
PREFIX = 'ASCII'
exif[0x9286] = (PREFIX + (8 - len(PREFIX)) * ' ' + 'a' * 8).encode('ascii')
imageCropped.save('test.png', exif = exif)

exiftool test.png

Output:

ExifTool Version Number         : 12.76
File Name                       : test.png
Directory                       : .
File Size                       : 163 bytes
File Modification Date/Time     : 2025:12:26 21:21:50+01:00
File Access Date/Time           : 2025:12:26 21:21:41+01:00
File Inode Change Date/Time     : 2025:12:26 21:21:50+01:00
File Permissions                : -rw-rw-r--
File Type                       : PNG
File Type Extension             : png
MIME Type                       : image/png
Image Width                     : 100
Image Height                    : 100
Bit Depth                       : 8
Color Type                      : RGB
Compression                     : Deflate/Inflate
Filter                          : Adaptive
Interlace                       : Noninterlaced
Exif Byte Order                 : Big-endian (Motorola, MM)
User Comment                    : aaaaaaaa
Image Size                      : 100x100
Megapixels                      : 0.010

DuckDuckGo and Google search `"LookupError: unknown encoding: unicode"`. DuckDuckGo search *Python unicode string*. https://docs.python.org/3/howto/unicode.html ```python exif[0x9286] = ('a' * 8).encode() ``` results in the warning. [python-pillow/Pillow/issues/5254](https://github.com/python-pillow/Pillow/issues/5254) DuckDuckGo and Google search *JIS*. [Wikipedia: JIS (1187947658)](https://en.wikipedia.org/w/index.php?title=JIS_encoding&oldid=1187947658) <details> <summary>Python script:</summary> ```python from PIL import Image imageCropped = Image.new('RGB', (100, 100)) exif = imageCropped.getexif() PREFIX = 'ASCII' exif[0x9286] = (PREFIX + (8 - len(PREFIX)) * ' ' + 'a' * 8).encode('ascii') imageCropped.save('test.png', exif = exif) ``` </details> ``` exiftool test.png ``` <details> <summary>Output:</summary> ``` ExifTool Version Number : 12.76 File Name : test.png Directory : . File Size : 163 bytes File Modification Date/Time : 2025:12:26 21:21:50+01:00 File Access Date/Time : 2025:12:26 21:21:41+01:00 File Inode Change Date/Time : 2025:12:26 21:21:50+01:00 File Permissions : -rw-rw-r-- File Type : PNG File Type Extension : png MIME Type : image/png Image Width : 100 Image Height : 100 Bit Depth : 8 Color Type : RGB Compression : Deflate/Inflate Filter : Adaptive Interlace : Noninterlaced Exif Byte Order : Big-endian (Motorola, MM) User Comment : aaaaaaaa Image Size : 100x100 Megapixels : 0.010 ``` </details>

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Reference: Benjamin_Loison/Pillow#6

exiftool *Warning* *Invalid EXIF text encoding for UserComment* if specify more than 8 characters #6

`exiftool` Warning Invalid EXIF text encoding for UserComment if specify more than 8 characters #6