Today I came upon some news weird enough to justify a post on this long-dormant blog. Ars Technica reports that it “began on January 30 and afflicted Mazdas from model years 2014 to 2017 when the cars were tuned to the local NPR station, KUOW 94.9. At some point during the day’s broadcast, a signal from KUOW caused the Mazdas’ infotainment systems to crash—the screens died and the radios were stuck on 94.9 FM.”
That shouldn’t be possible, right? A broadcast FM signal is just frequency-modulated audio. It might deafen you or damage the speakers, but it shouldn’t make the receiver stop working! Well, actually, it isn’t just audio. Broadcasters can optionally use the Radio Broadcast Data System (RBDS), which supports encoded digital data. It uses a 57 kHz subcarrier, well above the limits of human hearing. The data is encoded at 1187.5 bits per second, a strange-sounding number that yields 48 cycles of the subcarrier for every bit. Error correction codes bring the effective data rate down to 730 bits per second.
I’m not entirely sure where the right place to put this is. It’s a file format issue in part, since if people can’t keep using Finale after a macOS upgrade, they need to salvage all the files they’re created in its proprietary format.
The email which I got from MakeMusic, dated October 18, was alarming:
Finale v25.5 is not compatible with macOS 10.15 Catalina and will not be updated to support Catalina. It is our recommendation that users of Finale v25.5 not upgrade to macOS Catalina.
Most of today’s programming languages look vaguely similar. They’re derived from the C syntax, with similar ways of expressing assignments, arithmetic, conditionals, nested expressions, and groups of statements. If the files have their original extension and it’s accurate, format identification software should be able to classify them correctly.
JHOVE 1.22 is now available from OPF.
Malware has shown up which takes advantage of a path traversal bug in the WinRAR archiving utility. The bug, which reportedly existed for 19 years, is fixed in the latest version. The problem stems from an old, buggy DLL which WinRAR used. It allowed the expansion of an archive with a file that would be extracted to an absolute path rather than the destination folder. In this case, the path was the system startup folder. The next time the computer was rebooted, it would run the malware file.
MacOS provides a few different ways to do screen captures. My personal favorite is Grab, which is found in the Applications/Utilities folder. It lets me capture a selection, a window, or the whole screen without having to remember any magic key combinations. I keep it in the Dock for quick access.
Grab has one deficiency, though. It can save screenshots only as TIFF files. If Apple had to pick just one format, that’s hardly the most useful one. But there’s an easy workaround.
After you’ve got your screen shot, press Command-C or choose “Copy” from the Edit menu. Open the Preview application. Press Command-N or select “New from clipboard” from the File menu. You now have the screenshot in Preview.
In Preview, press Command-S or choose “Save…” from the File menu. You’ll get a dialog to save the file, with a choice of formats: JPEG, JPEG2000, OpenEXR, PDF, PNG, or TIFF. Pick whichever one you like. If you’re going to put the image into a Web page, PNG is usually the best choice. Preview will remember your choice for next time. Then save the file.
If you prefer, you can do the equivalent in Photoshop, Gimp, or any other image-processing application, but Preview has the advantage of launching quickly and keeping the process simple.
That’s it. You can now use Grab to save screenshots to a Web-friendly format.
Articles about JHOVE, such as Good GIF Hunting, grab my attention for obvious reasons. This article talks about false positive and negative results, and got me to thinking: What constitutes a “positive” result in file format validation? There are two ways to look at it:
- The default assumption is that the file is of a certain format, perhaps based on its extension, MIME type, or other metadata. The software sets out to see if it violates the format’s requirements. In that case, a positive result is that the file doesn’t conform to the requirements.
- The default assumption is that the file is just a collection of bytes. The software matches it against one or more sets of criteria. A positive result is that the file matches one of them.
Libtiff 4.0.9 has been released. According to the email announcing it:
A great many security improvements have been implemented by Even Rouault.
Much thanks to OSS Fuzz, team OWL337, Roger Leigh, and of course Even Rouault.
Obligatory reminder: Don’t download from libtiff dot org. It’s many years out of date.
An Open Preservation Foundation webinar, “Putting JHOVE to the acid test: A PDF test-set for well-formedness validation in JHOVE,” will be held on November 21, 10 AM GMT (that’s 11 AM in Central Europe and a ludicrous 5 AM or earlier in the US).
Popular Science has an article, “How to convert any file to any format.” The title overreaches, but the article actually isn’t too bad. It’s addressed at the ordinary user, not the file format specialist, so it wouldn’t be appropriate to complain too much that it has more breadth than depth.
It starts by recommending using the application that created the file, and that’s certainly good advice. Even when formats are open standards, an app knows more about how it creates its own files than anyone else does. Its files might have bits of application-specific information.
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