True EIA-708 captions can be achieved without the use for an external HD captioning encoder that can cost well over $8000 (US) by using a new captioning work flow.
What You Need
You need Final Cut Pro 7, an AJA Kona card (3, LHi or LSe), and the most recent Kona drivers. Of course, you will also need a special caption file created by a closed captioning service like Aberdeen Captioning (ONLY created using CPC/Mac Caption software).
What You Get
If you have the above-mentioned hardware and software, you can create the HD master caption tape in various HD tape formats, create HD captions for optical disc format delivery, and create captions for web video--and all of this can be done in-house without having to ship anything back and forth with a caption company.
How it Works
The AJA Kona cards ($1490 US) function as an HD encoder and place the captions in the accurate area in the HD video data. Here's how:
The closed captioning file that you receive is then imported into Final Cut Pro 7 and it doesn't require you to do any rendering. Final Cut Pro 7 has been designed to accept this caption file and in conjunction with the AJA card, it places the caption data into the correct location in the video being laid to tape.
AJA, Final Cut Pro, and CPC have all worked together to create this new technology.
Note: This workflow can also work for SD video if needed.