Improving Live TV Timeshift Performance

[smajor]

sub,

I'm interested in improving my Live TV time-shifting performance, I suppose cost vs. benefit is a big factor. Just a quick question about the internal temp cache for the Live TV Buffer...

GB-PVR had almost an "instant on" for Live TV, NPVR has a 4-5 second delay for starting live TV and changing channels.

I'd like to know how the buffer "behaves" if it runs out of drive space. I'm thinking that time-shifting will be a whole lot faster if I used a RAM disk. We don't pause an entire show, we'll pause and maybe get a commercial or two behind. 1 GB or 2 in a RAM disk would probably be plenty, and RAM is cheap. I can just set it up and point the Live TV buffer at the driver letter.

The question, of course, is what happens if it DOES fill up. With NPVR handle that in a graceful manner?

Am I overlooking something else, without all the above, that would increase that performance easily?

[sub]

In theory, it should be pretty much the same as GBPVR's live preview mode until you hit either pause or skip back (ie, no buffers involved), which is when it switches playback from the buffer. Thats what I get here. It takes about a second or so to change channels. I doubt placing the buffer files on a RAM disk would make any difference, until you press skip or pause, because its not using those files.

If you bump the thread in a couple of days (when I'm back home), then I'll see if we can work out why yours is taking so long.

[smajor]

Hi sub, thanks for looking at this. NPVR log attached. Here is what I'm seeing on my end:

From the main menu, select Live TV:

+1 sec, I see the channel change on my STB (exe channel changer fired).

+3 sec, HD-PVR LED comes on.

+3 sec, first image on TV.

7 seconds total.

Right after this, I fired up GB-PVR on the same computer. All that happened in about 2 secs.

[sub]

Ah, HDPVR - this isnt something I test, so I've got no idea how long it takes.

At the end of the day, startup time isnt really that important me. Time between channels is more important. There is some things done slightly different order in NPVR to work around bugs in the HD-PVR IR Blaster support, and this does add a bit of time.

Personally, I've always seen the HDPVR as more of a recording device than a live tv device. This is pretty much my view of any capture devices controlling set top boxes with blasters etc.

[smajor]

Well, fair enough I suppose. I never bothered with the blaster with all the bugs I read of here. I use Firewire Channel Changing.

For us, the HD-PVR is the only game in town. We're in a rural area and we get zero HD channels over the air. Nothing. I have to go with cable (or sat TV) and either way that amounts to STBs and Comp inputs. So, for us it's a Live TV viewing device first and a recording device second.

The channel changing between channels is a bit better at about 4 seconds.