Frame accurate captions: why anything less is not an option

Subtitle demo

When I’m explaining CaptionHub to people who haven’t spent their professional lives in broadcast video, I often have to pause. Some things about broadcast video, frankly, are just not that interesting.

But just because something’s not terribly interesting doesn’t mean it’s not important.

Take a video frame, for instance. Here in a Europe, there are generally 25 individual video frames that make up a single second of broadcast. (Our American cousins have even more.) So each frame is on screen for 40 milliseconds. An eye blink, in comparison, can last ten times longer than that.

Here at CaptionHub, we’ve invested huge resources into making sure that our software is frame accurate, that the captions we create are at the precise point that we say they are. I won’t bore you with the details, but true frame accuracy for a web-based application is hard. Really hard.

So, why did we bother?

It’s a fair point. After all, it’s only a few milliseconds. Who’s really going to care whether a caption starts or finishes at an exact time?

Actually, just about everyone. 40ms is easily inside the range of human perception. Take a look at the clip below:

Subtitle demo

Looks good, doesn’t it? Nothing jarring about that. Now take a look at this:

Seamless subtitle demo

The subtitles on this clip miss the edit point. It’s fairly subtle, but it’s definitely noticeable; I’d go so far as to say it’s slightly uncomfortable.

Still, you may be saying, surely it’s not that big a deal. In a limited instance like the videos above, sure: I agree. But consider the cumulative impact of poorly timed subtitles, which translates to an increasing level of discomfort. Consider further those who rely most on subtitles, whether they’re hard of hearing, or non-native language speakers. They’re having to work much harder to watch a video anyway. We should be doing whatever we can to ease that burden.

This is precisely why brands, broadcasters and film distributors – organisations like the BBC, Netflix, Sky and Apple – all mandate that captions need to be frame accurate.

These organisations have respect for their audiences. I think we all should.

Take a free demonstration of CaptionHub today and realise how to create seamless frame accurate captions.