todo

Red-Button

got an "Out of memory" error when doing avstream and video changed size
(start of C4 news)
can't see how avstream can cause an out of memory error

Sky Teletext - can't find PIDs for tags 1 and 2
BBC News Multiscreen - can't find default a/v PIDs

look into new splice() and tee() syscalls in 2.6.17 kernel for avstream

be able to read from a file

use a linked list of modules rather than an array in struct carousel
=> easier to delete/add modules

transactionId in DII messages is a version number
=> need to download again if it gets bigger
(we currently just look at the module version, is this enough?)

create carousels/PID/CID dir in add_dsmcc_pid()
(may need to use carousels/<assoc_tag> as stream2pid may return 0)