Why Netflix Doesn’t Offer Subtitles or Closed Captions

Netflix’s (s NFLX) chief product officer, Neil Hunt, wrote an interesting blog post today about why his company doesn’t offer subtitles or closed captions on its streaming content.

Evidently, adding subtitles and closed captions is harder than it looks. English subtitles don’t need to be added to most English movies (they are “burned in” to the stream for foreign language movies), so the company needs to figure out a way to let individuals turn the words on or off. But as Hunt writes:

Encoding a separate stream for each title is not an option – it takes us about 500 processor-months to make one encode through the entire library, and for this we would have to re-encode four different formats. Duplicating the encoded streams is prohibitive in space too.

So we are working on optionally delivering the SAMI file (Synchronized Accessible Media Interchange), or similar, to the client, and having it render the text and then overlay it on the video at playback time. Unfortunately, the tools for rendering SAMI files in Silverlight, or in CE (Consumer Electronics) devices, are weak or non-existent, and there is some technology development required.

Rep. Edward Markey (D-MA) introduced a bill last year to ensure that people with disabilities have access to web video, but according to GovTrack.us it never became law. YouTube (s GOOG) has had captioning capabilities for its videos since August of last year. Hunt predicts that subtitles and captions will be available for Netflix Silverlight users sometime in 2010, and then will be migrated to other TV connected devices by working with each manufacturer from then on.