Could you please give a more detailed explanation of how it does that without using an extra tuner? Only having 5 tuners is the only thing keeping me away from DTV. Thanx
Sure. Disclaimer here: I am no expert on the inner workings of DirecTV's DVR software. I have just read a lot on the internet, so please do not take my word as gospel. This may be a total misunderstanding on my part, but I have seem multiple people claim this is how it works with few if any arguing against it. If I am wrong about any of this, please let me know.
Most DVRs, including Tivos and maybe Dish's, handle the padding or buffer that is added to the beginning or ending of recordings which take place on
the same channel in adjacent time-slots by recording the same channel on another tuner for the duration of the overlap. For those few minutes, the DVR is using 2 tuners to record the same channel, thereby tying up those tuners for a short, but significant amount of time which may cause conflicts if you want to record more things at that time than there are tuners available to handle the demand, even though the total number of recordings you want to start or end at a given hour is less than the total number of tuners available.
DirecTV DVRs handle the padding by recording both shows on the same tuner, and somehow making sure the overlap ends up on both recordings. BEHOLD my seriously simplified diagram to try to illustrate the point:
FWIW: Dish's PTAT recording works kind of like DirecTV's from what I could tell when I had it, although with recording 4 streams at once, it is probably more complicated than that. Also, I think Dish will just truncate the recordings at the hour if you use the standard padding values. This can create situations where you go to watch a show you recorded months earlier and the beginning or ending are missing unexpectedly, and the adjacent show which caused this to happen is no longer on your DVR. Of course, with 16 tuners on the Hopper3, this should be less of an issue in theory.
Also of note is DirecTV now offering the HS17 with 7 tuners, and you could also add HR24s to the HR54 Genie to get more tuners that way. I hope that helped more than confused.