Just a couple of quick notes in case it's useful to anyone...
Recording portions of the broadcast for later viewing, found as expected the HD & std. digital streams are not protected since NBC is a OTA broadcaster, though they may be time limited, have an expiration date. Recordings -- saved portions of the stream -- are large as NBC is using a higher bit rate. If using win7's Media Center, win7 itself can easily convert .wtv to .DVR-MS without re-encoding -- Google for the fix if you don't see this conversion on the context menu when you right click a .wtv file.
Similar conversion to more standard mpg2 files [.mpg] can be handled by several apps/methods, again without re-encoding... the free MCTVConverter *usually* works, though I tend to use Roxio myself -- drag the DVR-MS file into Videowave & it'll offer to do the conversion.
For subs I've had a bit of a problem using the free ccextract on the saved NBC files, but the free SCC Tools works well on the de-muxed [no audio] mpg2 file. The result is a .srt text file that can be used by several apps/players. While CC is embedded in the mpg2 stream, it's difficult to play or display that embedded CC. While there are several free tools to work with .srt files, I've found the most useful of the lot to be the free Subtitle Workshop. Since the original CC is embedded I've found it works best to do any trimming &/or simple cut editing of the mpg2 video beforehand using a mpg2 editing app that doesn't re-encode, e.g. the apps from Womble or the free Cuttermaran... that way you don't have to worry about shifting the timing of the subs. I use Sony's DVDA [DVD Architect] because it allows you to shift, edit, & add/delete subs, either individually or including the rest of the sub track -- the DVD & Blu-Ray formats can often be the easiest way for me to package everything for playback with/without sub display, though my Android tablet's built-in player works with .srt files. [Using VLC Mobile Beta that tablet will also play Nero Digital (AVC) files with embedded subs I get using Recode to convert from the DVD format.]
Both the mpg2 video & the 5.1 AC3 audio included in the NBC HD stream are in a bit non-standard format -- the ATSC standards they're a part of are rather broad -- meaning you may or may not have problems playing those files as-is depending on the player [hard or software] you're using. AC3's also a bit iffy when doing any trimming &/or editing. I tend to re-encode both, 1st separating the streams [video & audio], then converting the AC3 to .wav, & then to whatever format needed after trimming & optionally editing. There are several free tools for working with, converting AC3 files, but note that if you want to keep all 6, separate channels in a 5.1 SC3 file, there are 2 .wav formats possible, a special version of .wav & .w64 [wave 64]. The latter [.w64] is better because all .wav files have serious size limitations in Windows -- getting over 2 GB can be challenging, while the 6 audio channels for a couple hour recording can total 4 GB+.
My general philosophy with video I've recorded is that any processing done while I'm doing something else is pretty much cost free... Yes it is a bit of trouble re-encoding or converting a recording that can be watched perfectly fine as-is, but if I keep any hands-on stuff to the barest minimum, my PC can do whatever conversions etc. while I'm not sitting at my desk, when it would be asleep otherwise. Say for example I'm going to put a recording on a Blu-Ray rewritable disc -- rather than spend time editing out commercials I'll maybe add a chapter when they end, so at the start of a commercial break I'll hit the Next button on the remote. Putting a recording on a Blu-Ray disc takes a bit of time, but very little hands-on effort -- the result is quicker easier to play on TV using the Blu-Ray player compared to firing up & setting up whatever player on my PC.