如何比较字段标签为 37680 (0x9330) 的 TIFF 文件？

Question

我们假设两个 TIFF 文件除了标签（根据网络搜索）“MSPropertySetStorage”/“OLE Property Set Storage”之外可能相同：

$ ls -l f1.tif f2.tif | cut -d ' ' -f 5,11
2211838 f1.tif
2211838 f2.tif
$ tiffcmp f1.tif f2.tif 
TIFFReadDirectory: Warning, Unknown field with tag 37680 (0x9330) encountered.
TIFFReadDirectory: Warning, Unknown field with tag 37680 (0x9330) encountered.
Directory 1:
Directory 2:
Directory 3:
Directory 4:
Directory 5:
$ tiffcmp -l f1.tif f2.tif
TIFFReadDirectory: Warning, Unknown field with tag 37680 (0x9330) encountered.
TIFFReadDirectory: Warning, Unknown field with tag 37680 (0x9330) encountered.
Directory 1:
Directory 2:
Directory 3:
Directory 4:
Directory 5:
$ tiffcmp -t f1.tif f2.tif
TIFFReadDirectory: Warning, Unknown field with tag 37680 (0x9330) encountered.
TIFFReadDirectory: Warning, Unknown field with tag 37680 (0x9330) encountered.
Directory 1:
Directory 2:
Directory 3:
Directory 4:
Directory 5:
$ diff -a f1.tif f2.tif | wc -c
180436
$ tiff2pdf -o f1.pdf f1.tif
TIFFReadDirectory: Warning, Unknown field with tag 37680 (0x9330) encountered.
TIFFReadDirectory: Warning, Unknown field with tag 37680 (0x9330) encountered.
TIFFReadDirectory: Warning, Unknown field with tag 37680 (0x9330) encountered.
TIFFReadDirectory: Warning, Unknown field with tag 37680 (0x9330) encountered.
$ tiff2pdf -o f2.pdf f2.tif
TIFFReadDirectory: Warning, Unknown field with tag 37680 (0x9330) encountered.
TIFFReadDirectory: Warning, Unknown field with tag 37680 (0x9330) encountered.
TIFFReadDirectory: Warning, Unknown field with tag 37680 (0x9330) encountered.
TIFFReadDirectory: Warning, Unknown field with tag 37680 (0x9330) encountered.
$ diff -a f1.pdf f2.pdf
11,12c11,12
< /CreationDate (D:20240428152134)
< /ModDate (D:20240428152134)
---
> /CreationDate (D:20240428152145)
> /ModDate (D:20240428152145)

输出结果exiftool稍微多一点，但仅此而已：

$ diff <(exiftool f1.tif) <(exiftool f2.tif)
2c2
< File Name                       : f1.tif
---
> File Name                       : f2.tif
5c5
< File Modification Date/Time     : …
---
> File Modification Date/Time     : …
$ exiftool f1.tif
ExifTool Version Number         : 12.57
File Name                       : f1.tif
Directory                       : .
File Size                       : 2.2 MB
File Modification Date/Time     : …
File Access Date/Time           : 2024:04:29 09:46:03+02:00
File Inode Change Date/Time     : 2024:04:29 09:42:41+02:00
File Permissions                : -rw-r--r--
File Type                       : TIFF
File Type Extension             : tif
MIME Type                       : image/tiff
Exif Byte Order                 : Little-endian (Intel, II)
Image Width                     : 1700
Image Height                    : 2338
Bits Per Sample                 : 8
Compression                     : LZW
Photometric Interpretation      : RGB Palette
Samples Per Pixel               : 1
Rows Per Strip                  : 7
X Resolution                    : 96
Y Resolution                    : 96
MS Property Set Storage         : (Binary data 3072 bytes, use -b option to extract)
Predictor                       : None
Color Map                       : (Binary data 1536 bytes, use -b option to extract)
Subfile Type                    : Full-resolution image
Strip Offsets                   : (Binary data 335 bytes, use -b option to extract)
Strip Byte Counts               : (Binary data 249 bytes, use -b option to extract)
Page Count                      : 6
Image Size                      : 1700x2338
Megapixels                      : 4.0
$ diff -a <(exiftool -b f1.tif) <(exiftool -b f2.tif) | wc -c
10776

我们在命令输出中看到的唯一有意义的部分diff -a <(exiftool -b f1.tif) <(exiftool -b f2.tif)是创建文件的用户的名称，后跟重音符 ` (U+0060) 和Microsoft Office Document Imaging 1.03.2349.01。

在查看器中查看 f1.tif 的六页，evince再查看 f2.tif 的六页evince，我们注意到没有区别，但这些文件是（可能经过后期处理的）打字和手写小文本的扫描件，因此一切都不准确。此外，evince可能还忽略了标签。

1. 如何获取具有上述特定标签 37680（0x9330）的字段的内容并在文件之间进行比较，以便比较结果对人类读者有意义？

2. 我们如何才能有意义地说明或直观地了解 180436 字节的差异diff -a f1.tif f2.tif和 10776 字节的差异diff -a <(exiftool -b f1.tif) <(exiftool -b f2.tif)是什么？这些命令会产生难以理解的垃圾。