clear_exif() / clear_iptc() / clear_xmp() not clearing Comment field

[dgtlmoon]

        exiv_image = pyexiv2.Image(filepath)
        exiv_image.clear_exif()
        exiv_image.clear_iptc()
        exiv_image.clear_xmp()

then I look at the file with exiftool

ExifTool Version Number         : 11.16
File Name                       : ab95627d37e9f9baecea24ee52b6377e.jpg
Directory                       : /var/www/tshirtslayer/web/files-tshirt/styles/shirtview/public/user-11635
File Size                       : 35 kB
File Modification Date/Time     : 2020:12:25 21:13:06+00:00
File Access Date/Time           : 2016:01:15 06:02:14+00:00
File Inode Change Date/Time     : 2020:12:25 21:13:06+00:00
File Permissions                : rw-rw-r--
File Type                       : JPEG
File Type Extension             : jpg
MIME Type                       : image/jpeg
JFIF Version                    : 1.01
Resolution Unit                 : inches
X Resolution                    : 96
Y Resolution                    : 96
Comment                         : CREATOR: gd-jpeg v1.0 (using IJG JPEG v80), quality = 80.
Image Width                     : 856
Image Height                    : 482
Encoding Process                : Baseline DCT, Huffman coding
Bits Per Sample                 : 8
Color Components                : 3
Y Cb Cr Sub Sampling            : YCbCr4:2:0 (2 2)
Image Size                      : 856x482
Megapixels                      : 0.413

I was hoping that

Comment : CREATOR: gd-jpeg v1.0 (using IJG JPEG v80), quality = 80.

would be gone

I'm also unable to override that with

            exiv_image.modify_exif({'Exif.Image.DocumentName': description,
                                    'Exif.Image.ImageDescription': description,
                                    'Exif.Photo.UserComment': description,
                                    'Exif.Image.Copyright' : "Copyright Creative Commons 3.0",
                                    'Exif.Image.DateTime': exif_date,
                                    'Exif.Image.DateTimeOriginal' : exif_date,
                                    'Exif.Photo.DateTimeDigitized' : exif_date,
                                    }
                                   )

ideas? file attached

[dgtlmoon]

after

        exiv_image.clear_exif()
        exiv_image.clear_iptc()
        exiv_image.clear_xmp()

exiftool with -v gives..

  ExifToolVersion = 11.16
  FileName = ab95627d37e9f9baecea24ee52b6377e.jpg
  FileSize = 35564
  FileModifyDate = 1608930786
  FileAccessDate = 1452837734
  FileInodeChangeDate = 1608930786
  FilePermissions = 33204
  FileType = JPEG
  FileTypeExtension = JPG
  MIMEType = image/jpeg
JPEG APP0 (14 bytes):
  + [BinaryData directory, 9 bytes]
  | JFIFVersion = 1 1
  | ResolutionUnit = 1
  | XResolution = 96
  | YResolution = 96
  | ThumbnailWidth = 0
  | ThumbnailHeight = 0
JPEG DQT (65 bytes):
JPEG DQT (65 bytes):
JPEG COM (58 bytes):
  Comment = CREATOR: gd-jpeg v1.0 (using IJG JPEG v80), quality = 80.
JPEG SOF0 (15 bytes):
  ImageWidth = 856
  ImageHeight = 482
  EncodingProcess = 0
  BitsPerSample = 8
  ColorComponents = 3
JPEG DHT (29 bytes):
JPEG DHT (179 bytes):
JPEG DHT (29 bytes):
JPEG DHT (179 bytes):
JPEG SOS

[LeoHsiao1]

An interesting picture. However, Github will automatically delete the metadata of your uploaded images, which is more thorough than my pyexiv2. Please send the picture to my mailbox and I will test it.

[dgtlmoon]

@LeoHsiao1 You should try to look at the data before making sweeping assumptions..

$ curl -q https://user-images.githubusercontent.com/275001/103142222-071f5c80-4700-11eb-9425-55cfc6d440e0.jpg|exiftool -|grep Comment
Comment                         : CREATOR: gd-jpeg v1.0 (using IJG JPEG v80), quality = 80.

I see it directly from github..

[dgtlmoon]

Can it be that this comment field is not part of the EXIF dataset?

[LeoHsiao1]

I parse your image with exiv2, and the metadata displayed is empty:

C:\Users\Leo>exiv2-0.27.2-2017msvc64\bin\exiv2.exe print D:\1.jpg
File name       : D:\1.jpg
File size       : 35564 Bytes
MIME type       : image/jpeg
Image size      : 856 x 482
D:\1.jpg: No Exif data found in the file

Then I parsed it with exifTool and showed that comment belonged to the JPEG tag.

$ ./exiftool ../1.jpg -v
  ExifToolVersion = 12.13
  FileName = 1.jpg
  Directory = ..
  FileSize = 35564
  FileModifyDate = 1608978733
  FileAccessDate = 1608979346
  FileInodeChangeDate = 1608979348
  FilePermissions = 33279
  FileType = JPEG
  FileTypeExtension = JPG
  MIMEType = image/jpeg
JPEG APP0 (14 bytes):
  + [BinaryData directory, 9 bytes]
  | JFIFVersion = 1 1
  | ResolutionUnit = 1
  | XResolution = 96
  | YResolution = 96
  | ThumbnailWidth = 0
  | ThumbnailHeight = 0
JPEG DQT (65 bytes):
JPEG DQT (65 bytes):
JPEG COM (58 bytes):                    # <--- here
  Comment = CREATOR: gd-jpeg v1.0 (using IJG JPEG v80), quality = 80.
JPEG SOF0 (15 bytes):
  ImageWidth = 856
  ImageHeight = 482
  EncodingProcess = 0
  BitsPerSample = 8
  ColorComponents = 3
  YCbCrSubSampling = 2 2
JPEG DHT (29 bytes):
JPEG DHT (179 bytes):
JPEG DHT (29 bytes):
JPEG DHT (179 bytes):
JPEG SOS

[dgtlmoon]

https://stackoverflow.com/questions/17447201/how-do-text-comments-in-jpg-files-work

[dgtlmoon]

So what todo? I guess this is not part of your library?

[LeoHsiao1]

In short, JPEG COM is part of the JPEG image structure and is not a generic metadata standard.

[dgtlmoon]

OK, yeah I think probably good enough..

[github-actions[bot]]

This issue has been automatically closed because there has been no activity for a month.