After spending many hours playing with wireshark and perl scripting, you can now download Hulu.com closed-captions / subtitles with get_iplayer v1.33+. Since I am in the UK, I had to set up a SOCKS proxy on a US based ssh server. By using:

ssh -D 1080 [server ip]

and then installing tsocks to transparently redirect all network traffic from my system via the US based server, then running up firefox to play a Hulu flash-based movie and clicking the ‘CC’ button, I was able to network sniff for the web requests that obtained the Subtitles. Simple really.

I’ve converted the SAMI subtitle stream to SubRip format because it seems to be the most widely supported subtitle format (see this comparison).

So all you need to do now is run:

get_iplayer --type hulu --subtitles --get [search terms]

Having recently noticed that subtitle support is now widely available on the iPlayer website, I thought I’d have a go at providing the ability for get_iplayer to download them (from version 0.61 onwards). So after some packet sniffing and perl hacking I have added subtitle support. It downloads the subtitles in W3C Timed Text format (see this post) and converts them into a more widely supported format, i.e. SubRip (.srt).
There is a rather annoying caveat though; The iPhone H.264 iplayer streams do not exactly match the flash versions; They often start a few seconds earlier which results n the subtitles being shown too early and out of sync with the audio So, as a workaround, I’ve added an option to munge the subtitle timestamps during download to add an arbitrary offset in milliseconds
To use this feature the program must, of course, have subtitles. You need to use the –subtitles option and optionally –suboffset nnnn, e.g:

get_iplayer –get Miller –subtitles –suboffset 3500

SubRip appears to be supported by mplayer, xine and vlc so hopefully you’ll be able to try this out.