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Set Comment: Which field in JPEG file?

Posted: Wed Oct 12, 2016 4:07 pm
by wctopp
I apologize for this. I'm not a graphics programmer. I'm using "set comment" to add a description to scanned family photos so I can get rid of the hard copy. In what field within the jpeg file does this comment text go? I cannot find it with a metadata viewer. I asked a metadata expert for help and he found the text physically, but he too could not identify it as any specific metadata field. Can anyone tell me where physically "set comment" puts things in the jpeg file? Thanks. Bill Topp

Re: Set Comment

Posted: Wed Oct 12, 2016 4:24 pm
by cday
wctopp wrote:I apologize for this. I'm not a graphics programmer. I'm using "set comment" to add a description to scanned family photos so I can get rid of the hard copy. In what field within the jpeg file does this comment text go? I cannot find it with a metadata viewer. I asked a metadata expert for help and he found the text physically, but he too could not identify it as any specific metadata field. Can anyone tell me where physically "set comment" puts things in the jpeg file? Thanks. Bill Topp
A quick Google produces this result among others, is this the information you are looking for?

JPEG Syntax and structure - Wikipedia

Re: Set Comment

Posted: Wed Oct 12, 2016 4:58 pm
by wctopp
So "set comment" puts text in "COM 0xFF, 0xFE variable size Comment Contains a text comment."? If the answer is "yes" thanks so much. I've asked two computer graphics programmers, an image analysis programmer, and a metadata expert this question and none could give me an answer. I'm tremendously grateful. What kind of program would show both the picture in the jpeg AND reveal the "COM" field?

Re: Set Comment

Posted: Wed Oct 12, 2016 5:07 pm
by cday
wctopp wrote:So "set comment" puts text in "COM 0xFF, 0xFE variable size Comment Contains a text comment."? If the answer is "yes" thanks so much. I've asked two computer graphics programmers, an image analysis programmer, and a metadata expert this question and none could give me an answer. I'm tremendously grateful.
I hope it is what you're looking for, never underestimate the power of a Google search!
wctopp wrote:What kind of program would show both the picture in the jpeg AND reveal the "COM" field?
I'd like to know that myself, I did see the capability in one of the web photo album creation programs a while back, possibly jalbum.net, but hopefully someone can name some photo viewers with the capability... :?:

Re: Set Comment

Posted: Wed Oct 12, 2016 6:23 pm
by wctopp
On the latter, anyone have any suggestions?

Re: Set Comment

Posted: Wed Oct 12, 2016 8:00 pm
by XnTriq
Welcome to the forum, Bill Topp :-)
wctopp wrote:What kind of program would show both the picture in the jpeg AND reveal the "COM" field?
XnView Classic:
  • Browser
    • Tooltip
      • Tools » Options... » Browser » Browser » [×] Show tooltips » Insert » Image » Comment
    • Status bar
      • Tools » Options... » Browser » Browser » Info in status bar » Comment
      • View » [×] Status Bar
    • Label
      • Tools » Options... » Thumbnails » Thumbnail Label » Comment
      • View » View As » Thumbnails & Labels
  • Viewer
    • Status bar
      • Tools » Options... » View » View » Info in status bar » Comment
      • View » [×] Status Bar
    • Title bar
      • Tools » Options... » View » View » Title bar » Insert » Image » Comment
    • Info
      • Tools » Options... » Fullscreen » Fullscreen » [×] Show information » Insert » Image » Comment
      • View » Show information
BTW: XnView allows you to copy JPEG comments to the IPTC Caption tag (Edit » Metadata » Copy Comment to IPTC Caption). You can also add a button for the command (cmd_CopyCommentIntoCaption) to the main toolbar.

Re: Set Comment

Posted: Wed Oct 12, 2016 9:48 pm
by wctopp
Under "Edit" I don't see an item "Metadata".

Re: Set Comment

Posted: Wed Oct 12, 2016 9:59 pm
by cday
wctopp wrote:Under "Edit" I don't see an item "Metadata".
In XnView Classic in the file browser (not viewer) Edit > Metadata...

In XnView MP in the file browser under Tools > Metadata...

My vision, though, is for an image viewer that will display a caption prominently below the image in the main image window, or something equivalent, rather than inconspicuously in the status bar or other part of the viewer window, or superimposed on the image...

Re: Set Comment

Posted: Wed Oct 12, 2016 11:57 pm
by wctopp
XnView MP 0.82, not "Classic". Must have changed. Thanks so much for trying. I also can't figure out how to get the icon in the tray as you suggest.

Re: Set Comment

Posted: Thu Oct 13, 2016 12:30 am
by XnTriq
<--// Moderator's note: This topic has been moved from Classic to MP. //-->

Re: Set Comment

Posted: Thu Oct 13, 2016 1:07 am
by wctopp
Ubuntu Linux, not Windows.

Re: Set Comment

Posted: Sun Mar 19, 2023 12:18 am
by BuckSkin
wctopp wrote: Wed Oct 12, 2016 4:58 pm What kind of program would show both the picture in the jpeg AND reveal the "COM" field?
FREE Windows only FastStone is the best I have found to display a jpeg image AND it's Comment.

In FastStone, when in normal/browser view = View > Image Properties and choose the JPEG Comment tab; this sizable window can be moved around and will remain visible, displaying the Comment for each jpeg selected in the browser.

When you switch to Full Screen, mouse over to the right and the Comment will appear, plenty large enough for easy reading; mouse away and it will disappear.

XnView has one advantage over FastStone when it comes to writing these comments; FastStone can only write to a single image at a time; whereas, XnView can batch write to one or a thousand (or more).