I just installed the 7216 and when I record some programs the status shows 18 hrs, 59 minutes of standard definition programming recorded and no HD programming. It reports that I have used 53% of the capacity. If you do the math, that means that at 100% you would only have a total of 35.8 hrs. In Vz's sales pages, they say that you should be able to record "at least 80 hours". This is the fourth DVR that has been installed and they have all done about the same with capacity in the 30 to 35 hours neighborhood.
I have worked with tech support on this and their best comment is that some std.def content takes more space that others. Another says that the guide takes up some of that space. I have looked through all the menu items and could find no parameters that would seem to make my content take up more space than normal. Am I in a FIOS Bermuda Triangle here?
I did a quick search on the forum (SD Capacity 7216) , and found the following thread which appears to be similar to your experience:
My suggestion would be to try the theory out regarding some channels taking up more recording space.
Try recording a sports channel (say ESPN) for 1 or two hours and measure the increased percentage usage.
Then record another channel (like History Channel) for the same amount and see if the percent increase is the same or less.
The problem from what I understand is two fold.
1. there are sometimes when the dvr reports incorrect useage information.
that is fixable and you do that by going to start -> settings -> system info and enter in code 4883 to whipe the guide data
(you will see a success confrmation when this is executed properly) and then you reboot, and all is well in the universe again.
2. those numbers are marketing numbers that assume all SD is created equal, that a 1 hour program judge judy equals 1 hour of discovery. The problem with that theory is that these are VBR (variable bit rate) And so the more detailed and more going on with the station and more importantly the program, the more bits it takes to display the image. so high action VS law and order maybe. believe it or not there is a difference, and it can be huge sometimes, as much as 20-30% but shouldn't be much more than that.
So its tough to say how much will actually get recorded hours wise, but as far as space used, it goes like this 3.3mbps for SD, or 3,419,796.41 bits per sec = 1.433GB/hr = 94.19 hours into 134.64GB - the one hour LOD buffer = 85.8 hours of SD storage.
Same data for HD @ 13.7mbps, or 14,338,900.55bps comes out to 20.5 hours of HD storage.
Obviously, re-running the numbers with different bitrates yields different amount of capacity in hours.