A reader contacted me today to ask me about something odd he’s been experiencing with his TiVo Series3. He’s a Time Warner Cable user in Raleigh, NC, and lately they’ve been adding new HD channels using SDV in his area. The oddity is that he’s been able to tune in three of these channels – A&EHD, TBSHD, and GOLF/VSHD – on his Series3. This is odd because the S3 is physically incapable of tuning SDV channels, that’s what the Tuning Resolver that’s coming out in 2008 is for. He said that early on he got error messages that the channels were unavailable, as I’d expect, but that he’s been able to regularly tune them lately. This is very odd indeed, and I had three theories:

1. The channels aren’t actually SDV, but are standard linear channels and TWC just gave out bad info about them being SDV. The S3 would be able to tune these channels like any other cable channel. The earlier error messages could’ve been a coincidence – some unrelated problem. Or perhaps the guide was updated before the channels were live.

2. The channels did start out as SDV, but demand was high enough that they were always in use, so TWC just converted them to linear channels. That would explain the error and then the channels working regularly.

3. The channels are SDV, and someone else on his cable network segment has tuned the channels. When an SDV STB tunes an SDV channel the head end dynamically assigns the channel to a frequency and then tells the STB which frequency to tune for the channel. I suppose it is possible that this updated channel map is also being picked up by the CableCARDs in his S3, allowing him to tune in the SDV channel so long as someone else on his segment has previously requested it. He would lose access to the channel whenever no one else on his segment was viewing it. And it is just coincidence that his tests have fallen during times when the channels are in use.

Now, I did some poking around online, and from what I can tell those three channels are SDV in Raleigh, NC, and have been since they were added in October. That seems to indicate hypothesis number 3.

Has anyone else who lives in an area using SDV been able to tune SDV channels on their CableCARD TiVo? Can anyone else who lives in Raleigh confirm that these are SDV channels? Can you tune them, or any other SDV channels, with your TiVo?

I suppose the ultimate test would be someone who has SDV channels, a CableCARD TiVo, and a regular cable STB. Find an SDV channel that the TiVo cannot tune. Then tune that channel with your STB. That would cause the head-end to issue a frequency for the channel. Then try to tune it on your TiVo again. If it works on the TiVo, then we know the TiVo can tune SDV channels if they’re in use. Unfortunately, if it doesn’t work all it means is that it doesn’t work there. Different cable systems could handle the channel mapping data differently. So it not working in one location doesn’t mean the TiVo is incapable of doing it everywhere. (And it working in one location doesn’t mean it will work everywhere, but it does mean it could work.)