Finding and converting legacy media 1: still images

macOS 10.15, being 64-bit only, drops support for QuickTime 7 and all its codecs. In this series, I’m going to look at how to find and convert files which are most likely to be affected by this, starting with one of the simplest: JPEG 2000 images.

Most of the codecs which are becoming unsupported are those for video, but Apple’s list includes one still image format which could affect you, JPEG 2000. Although never popular, at some time in the past you may have saved photos or other images in this format, which is quite different from plain old JPEG (which won’t be affected by the loss of these codecs).

A quick check using my free UTIutility reveals that JPEG 2000 documents normally have the extension .jp2 or .JP2, although they can also use .jpf, .jpx, .j2k, or .j2c. Those are given the distinctive UTI of public.jpeg-2000, and these provide the information we need to search for them.


UTIutility can also scan folders and inform us of all the UTIs which it encounters. If you think you might have some JPEG 2000 images in your Pictures folder, for example, it is very simple to open its crawler and see whether public.jpeg-2000 appears in the list of UTIs found there.


To locate all your JPEG 2000 images, open a Finder window and select the Find command in the Finder’s File menu. Switch the search criterion to Kind, then set Other, and in the box paste the UTI public.jpeg-2000.


You’ll then see a listing of all the JPEG 2000 documents on your Mac, ready to convert.

If you inspect any of those images in the Finder, it should display their file type as JPEG 2000 rather than plain JPEG.


Most good image editors, including the king of conversion tools GraphicConverter, can open these and save them as regular JPEGs or PNG if you prefer. If you don’t have one of these apps to hand, use Preview instead. Simply open the image in Preview, and use the Export As… command in its File menu to convert and save the image in your chosen format.


It’s wise to make an archive copy of the original image, then simply replace each JPEG 2000 document with its JPEG or PNG conversion, and you’re done.

If you have other media files of distinctive types which become unsupported, you can use the same sequence to identify them. However this doesn’t work for container formats such as QuickTime movies which can include content encoded in a range of different formats, or for embedded encoded content.