How to set Per-channel tuner priorities?

[Frankenscript]

Hi folks,

I'm just getting started with NextPVR, coming from WMC. I've sorted out the usual firewall, video decoder, and EPG issues, thanks to searching the support forums and wiki and so on. But I've hit a snag that I couldn't find via search, so my first post is a request for clarification on how to do this presumably simple thing.

I've got four HDHomeRun OTA ASTC tuners available. Though they basically receive the same channels, each channel comes in decidedly better on some tuners than others. In WMC it's pretty straightforward to go in and set the priority order of the tuners within each channel's configuration. For the life of me, I can't figure out how to do this in NextPVR. Clearly, I'm missing something. Sorry for being dense.

Specifically, let's say the tuners are hypothetically named A, B, C, and D.

For channel 4.1 I want to assign tuner A as first priority for it and tuner B as second priority (and, possibly C and D as 3rd and fourth priority)
For channel 8.1 I want tuner B as first priority and Tuner D as second priority
For channel 59.1 I want Tuner A then C.
(and so on).

I've seen the tuner priority in devices, but that appears to be a global thing, with no per-channel settings. Not too useful if the signal for each channel comes in differently on different tuners.

I can't just make sure each desired channel appears on a single tuner's lineup, because conflicts happen with reasonable frequency.

How do people set this up? I've found nothing in the wiki or my search through the forums, so I'm starting to think this is a thing that NextPVR doesn't have, which would be a dealbreaker for my needs, unfortunately. I'm hoping I'm just looking at it the wrong way and there's a reasonable solution.

Please advise! Thanks in advance!

Marc

[Graham]

And the bad news ... NextPVR doesn't have the facility to set tuner priority for individual channels.

Plus, I don't understand how the problem can exist. Do all of the tuners receive their OTA signal from the same antenna? Can you amplify the antenna signal to get the same good quality signal at each tuner?

Edit: I suspect that I may know the answer to my question. Is it that different broadcasters use different transmitters requiring several antennas pointing in different directions? (In the UK most folk get all channels from a single transmitter).

[Frankenscript]

Hi Graham,

Thanks for the reply. And the information about NextPVR.

My situation is perhaps not unusual, just a bit strange. Where I live the terrain is flat and most of the transmitters are just about 8 miles from me in the same direction.

Basically, despite strong clear signal, I'm getting frequent breakups in WMC-recorded programs. Particularly on some shows (on certain channels) but it's kind of unpredictable. When I use the HDHomeRun utilities they show essentially 100% signal strength and symbol quality etc. Viewing these channels in QuickTV always is perfectly clear. While signal static can happen now and then, with the strong singal I have I don't know why I frequently get breakup many times during a show, sometimes every 10-15 seconds. And it comes in fits and starts. I'm starting to think my (old-ish) HTPC doesn't like to record while I am watching other content.

Anyway, I've tried to optimize my antennas to rule out signal issues. One antenna gives great VHF performance, another is optimized for UHF, and a third is a mix. My older HDHomeRun has two separate antenna inputs (VHF antenna goes in one, UHF in the other). The second HDHomeRun box has a single input (the blended antenna goes in there and feeds both of its tuners).

It seems to have gotten worse over time, to the point where I've got screwed up recordings and the wife is skeptical about watching anything recorded.

I decided to try recording on a different computer using different software, to see if changing that stuff would give better results.

I can probably arrange tuners and channel listings to come up with a reasonable arrangement, even if it is just for testing.

Thanks for the help!

Marc

[johnsonx42]

if you're that close to the antennas on flat terrain, you may be getting too much signal on some channels; this can over-drive the input stage of the tuner, like turning up an audio amplifier's pre-amp gain too much. try just using your uhf/vhf combo antenna, and put a splitter in to feed both of your HDHR's. That will act to attenuate the signal a bit. You might even have to put in a dedicated attenuator.

I'm 35 miles from the very powerful broadcast towers north of LA, and I can't get ABC (VHF 7) with any antenna connected directly to any tuner (nor on my TV's built-in tuner); it was only after putting in a 3-way splitter that I could finally receive it.

[Frankenscript]

Some of my problem may be dual-path issues, ground reflections, airplanes flying overhead, that kind of thing.

[Jaggy]

Basically, despite strong clear signal, I'm getting frequent breakups in WMC-recorded programs. Particularly on some shows (on certain channels) but it's kind of unpredictable. When I use the HDHomeRun utilities they show essentially 100% signal strength and symbol quality etc. Viewing these channels in QuickTV always is perfectly clear. While signal static can happen now and then, with the strong singal I have I don't know why I frequently get breakup many times during a show, sometimes every 10-15 seconds. And it comes in fits and starts. I'm starting to think my (old-ish) HTPC doesn't like to record while I am watching other content.

This is so much exactly the same symptoms I used to have I just had to reply to your message....

For me after years of trying to find the culprit (& blaming the signal for the breakups) I discovered that the problem was a lot less after a full computer cold boot & after some discussions on this forum I was talked into updating from XP to win7, due to outside circumstances I ended up just fitting a different boot drive & installing W7 on that very same (rather ancient) server which totally cured the problem for me (it's been great for over a year now).... but I'm fairly convinced (like 98%) that the real culprit was something to do with the boot drive & not the fact I was running XP as lots of users are still running XP without an issue.

[Frankenscript]

This is so much exactly the same symptoms I used to have I just had to reply to your message....

For me after years of trying to find the culprit (& blaming the signal for the breakups) I discovered that the problem was a lot less after a full computer cold boot & after some discussions on this forum I was talked into updating from XP to win7, due to outside circumstances I ended up just fitting a different boot drive & installing W7 on that very same (rather ancient) server which totally cured the problem for me (it's been great for over a year now).... but I'm fairly convinced (like 98%) that the real culprit was something to do with the boot drive & not the fact I was running XP as lots of users are still running XP without an issue.

Thanks for posting this experience. I would not be at all surprised if my own culprit was largely due to issues with my computer or the way it is used at the time of performing recordings (we are usually watching something else at the time). It is an older system, circa 2009 (Athlon X2 Kuma, 2.7 GHz), but has been upgraded over the years with a newer graphic card, an SSD for the OS, and has had Windows 7 since the pre-release ("RC1") days. It was most recently re-installed about 18 months ago, and at that time I hoped to cure any computer-specific ills. No dice. :-(

Meanwhile, I was able to record a test program last night. The resulting .ts file hardly plays at all on the desktop system I used to record it (a respectable, recent Core i5 system). Since I don't usually play .ts files (all my content is MKV) I'll need to investigate what renderer/codecs are being invoked. Interestingly MPC-HC stutters on the file too. I did a quick handbrake to an MKV file; that seems to play fine, though I haven't had time to watch it thoroughly for any "signal breakup" artifacts.

I will play around and do some experiments and see what I can figure out.

Thanks all!

Marc

[Graham]

Meanwhile, I was able to record a test program last night. The resulting .ts file hardly plays at all on the desktop system I used to record it

Simply stated, and with apologies if I'm stating the bleedin' obvious, there is no computing required to record a digital broadcast ... NextPVR simply copies the stream received from the tuner to disk. I would expect you to get smooth playback of a recorded file when the file was recorded with no other recording in progress (on any computer). Are the tuners network attached? Could there be a capacity problem on the network?

I am running a 2.1 GHz AMD processor on a four year old setup and I am able to record eight (or more) channels simultaneously (including several HD channels) while watching playback of an HD recording.

[Frankenscript]

Thanks, and don't worry about stating the bleedin' obvious! :-)

I understand and accept that the computer doesn't have to do much to copy the stream coming in on the (gigabit) network connection from the HDHomeRun to the hard disc (which is a SATA drive right there in the HTPC case, no network shares or anything). Still, since the computer is used to browse and view other (MKV) content at the same time, I had some thought that perhaps I was encountering some bottleneck unexpectedly causing it to drop frames and get glitchy.

It's not possible for me to rule out signal issues (too strong, multipath, improper aiming of antenna, etc.) but my observation has been that on the channels of interest, I can watch QuickTV (or now, the new FreeTV) from SiliconDust and not encounter glitches, but that same channel on the same tuner tends to produce intermittently glitchy recordings.

So, thoughts included issues with the computer itself including it's software environment, or Windows Media Center and it's recording mode. It seems when I play back glitchy recordings, the visual and audio interruption is relatively severe. As in, a single glitch typically results in at least a half second interruption in sound and video with the freezing and macroblocking effect. If I watch even a weak channel on QuickTV, with glitches due to weak signal, the glitches are a lot less intrusive, generally.

So, I figured WMC might be the culprit.

By using my (much) more powerful desktop PC (i5 4670) and different software (NextPVR) I eliminate two possible culprits at once. I can always transfer recordings down to the HTPC. No worries there.

I will record several shows on the most problematic channel, and see how it goes. The fact that I have trouble playing that first recording (as a .ts) on my powerful desktop is a bit surprising to me, but I've never tried playing a .ts file here... I may not have things set up properly (though, MPCHC ought to make short work of it, but didn't do much better). I will have to investigate that.

Marc

[sub]

You can also see if the 'Main Application' setting HDHomeRUn Setup to 'NextPVR' helps. This setting can greatly reduce the amount of data sent across the network. When its set to NextPVR it only sends the data for the channel you're watching/recording. Most other settings will send the complete transport stream, including other channels and data included on the same frequency.