Before moving to "what actually helps", the solution, I'd like to first address the problem very briefly.
What face blindness actually is
Face blindness (medically known as prosopagnosia) is a condition that prevents people from recognizing a face they've seen before. This includes friends, relatives, and, in severe cases, even themselves.
It's also a misconception that they see "scrambled faces", they don't. Instead, they see a clear, normal face but cannot connect it to an identity, and the next time that face appears, there's nothing to connect it to.
Why movies and TV are hard
If they cannot recognize people they see on a daily basis, imagine how difficult it'd be for them to link a name to a face for a simple 2-hour long movie with dozens of characters. There are different severities to this condition, but in the research I did for this project, difficulty with movies and TV shows came up again and again.
At the moment, they cope with this condition by utilizing non-facial clues, such as the person's voice, hair, clothing, posture, etc. In a movie or TV show, that means every time a character changes appearance, that's a new character they've never seen before. So, to keep track they may need to constantly ask "who's this character?" if they're with someone or look up "who's who in [movie]?" or "[movie] characters" on the Internet.
Things that can and have been helping
- Closed captions. The subtitles usually show the name of the person speaking through tags, i.e. "[Robert] Look over there!", which can help them link the person speaking at the moment with a character name in the story.
- Audio description. This one is underrated. AD tracks exist on most streaming platforms as an accessibility option, and the narration names characters as they appear on screen: "Robert enters the room." It was built for blind and low-vision viewers, but it happens to solve a good part of this problem too.
- External guides. Referring to a cast list or wiki constantly throughout the movie or TV show on a phone or laptop to check who is who.
- Non-facial clues. As mentioned above, distinct non-facial clues can be quite helpful whenever available. However, these may not always be present, so it could be less reliable.
- Animation. Animated movies and TV shows usually use vibrant designs and unique color palettes per character, which makes it easier to tell them apart.
- Watching with someone. Having someone you can always ask to clarify who is on the screen whenever you need help is very beneficial. Though some people may find it difficult or embarrassing to do so.
Tools
Now, with the advancement of technology, there are other more helpful tools that can allow affected people to not need CC, guides, or other people. One such tool is Face Recognition Track (FRT), which I built. It analyzes videos and generates a simple, custom .FRT file. This file can then be used to put a label on each face while you're watching, so the viewer can see who's on screen without having to work it out. This is what it looks like:
Sources
Most of the information in this article was based on my research while working on this project: searching on the Internet (Cleveland Clinic and Wikipedia) and even directly talking to people diagnosed with the condition (r/Prosopagnosia and r/SomebodyMakeThis/1ue69lu, where it all started).
If you've read this far, thank you for your time :)