This test is done on a gif file on Mac using exiftool 10.12.
exiftool -verbose 5abH_1484991728315_4d9b42ef_a234.jpeg
ExifToolVersion = 10.12
FileName = 5abH_1484991728315_4d9b42ef_a234.jpeg
Directory = .
FileSize = 335113
FileModifyDate = 1484991733
FileAccessDate = 1489051302
FileInodeChangeDate = 1489047135
FilePermissions = 33188
FileType = GIF
FileTypeExtension = GIF
MIMEType = image/gif
GIFVersion = 89a
ScreenDescriptor (SubDirectory) -->
+ [BinaryData directory, 7 bytes]
| ImageWidth = 250
| ImageHeight = 373
| HasColorMap = 128
| ColorResolutionDepth = 112
| BitsPerPixel = 7
| BackgroundColor = 255
Application Extension: NETSCAPE 2.0
ExtensionAnimation (SubDirectory) -->
+ [BinaryData directory, 5 bytes]
| AnimationIterations = 0
Image: left=0 top=0 width=250 height=373
Graphic Control: delay=0.00
Image: left=0 top=0 width=250 height=373
Graphic Control: delay=0.00
Image: left=0 top=0 width=250 height=373
Graphic Control: delay=0.00
Image: left=0 top=0 width=250 height=373
Graphic Control: delay=0.00
Image: left=0 top=0 width=250 height=373
Graphic Control: delay=0.00
Image: left=0 top=0 width=250 height=373
FrameCount = 6
The value of BitsPerPixel = 7 is probably incorrect. The 5th byte in Screen Descriptor of GIF file is 01110111. The three bold bits value is 7, and thus the value of Bits per pixel should be 8, according to http://www.martinreddy.net/gfx/2d/GIF87a.txt (Search for "# bits of color resolution"). It was the closest official document I could find.
Apologies if this post is a duplicate or the behaviour reported is intended of the application.
For gif file, you can use this link:- https://img0.ropose.com/story/1484290169397_475_25361880-6512-4b80-94a8-6a90ccdb0bc4.jpeg [The use of jpeg in extension is intentional]
You are looking at the "raw" values in the verbose output. This is before adding the +1 correction.
- Phil
Hi Phil,
Thank you for clearing this. :)