[Chip Chester]

There are a few various decoder fonts out there in TrueType, and a few more 'locked away' in long-discontinued decoder chips. Built-in decoders in sets used caption decoder chips in the early years, then 'graduated' to using the same chip used with on-screen menus. Sony and Trinitron Akai used the best-looking fonts of the day. The 'no descender' fonts (shown in your post) are kind of the classic, so-ugly-they're-cute fonts.

When you 'extract' these, is it destructive to the set/decoder, or to the chip? Or could you work with a digital file of the on-screen presentation of all the characters, as brought forth by the caption encode/decode process?

I have a collection of good, bad, and fantastic caption decoders (and similar devices) from the past 25 years or so. Also have equipment to generate and harvest both 608 and 708 caption data in any format. Don't overlook the nice-looking caption fonts in QuickTime, too... In pro broadcast hardware, EEG has some great-looking decoders. Evertz has some lousy ones. They both cost $3000.

Most current-day caption displays are driven via graphics chips within the set-top box, be it cable, satellite, or OTT/AppleTV/Roku-type device. The internal caption decoder in current sets is only used with over-the-air broadcasts, since the HDMI cable spec has no 'lane' for caption data at all.

As captioning progressed over the years, the allowable character sets expanded as well. First-generation was pretty limited, with barely enough character set support for English, Spanish, French, etc. Later versions (Telecaption II compatible stuff) expanded that set a bit, but limitations still existed. Limitations, like decoders couldn't display an asterisk *, for example, not because of chip limitations, but it was an 'illegal' character in caption data. Once HD/708 captions hit the scene, there was no practical limit to characters, and fonts/attributes were more in the hands of the viewer, and varied by set manufacturer/graphics chip design.

- Chip
(Closed-captioner for 25+ years. Feel free to PM me if you'd like.)