Overscheduled

[pabaxt]

This is my first post here, so hello and more importantly a huge thank you for a great product.

I've been using NPVR for a few months now on a dedicated i7 PC that does little else except host an instance of Plex to view recordings as an adjunct to my main Plex.

The PC has a Hauppage dual USB stick as the secondary tuner, the primary tuner is a quad HD Homerun. All recording from DVB-T. I'm in Yorkshire UK.

I initially had a few recordings flagged as failed, which I think were just teething issues. I've not really sen any failures recently and I've recorded over 1000 movies, most seemingly successful (though I've by no means checked them all!) but occasionally I would get recordings that were not marked as failed but that was very short or even invalid. I lacked the time to try and investigate these issues, so all I did was to grab a copy of the recording folder and then delete the recording through NPVR. I suspected that in some instances NPVR was allowing more simultaneous recordings that I had tuners (6 in total). Last night I was able to prove this by grabbing a copy of the database and writing some code to create a heat map of tuners in use for each 5-minute slot over the scheduled period, and I saw that I had 7 recordings in three close instances. These had been set up manually using the latest version and no recordings are recurring.

I have a copy of the heat map (the relevant part shown below) the database and logs but I could not attach the database (zipped) for some reason, so here's a link. https://1drv.ms/u/s!AgGgXm4PZDRho7w7Z6a5...w?e=reXdDQ

Here's an example that seems to show the same tuner allocated to two recordings:

oid  name           filename status start_time          end_time            capture_source_oid channel_oid recurrence_oid channel_name

2346 Nowhere to Run          0      2020-07-17 20:00:00 2020-07-17 21:55:00 27                 7694         0               Sony Movies Action
2347 The Pact                0      2020-07-17 20:00:00 2020-07-17 21:50:00 27                 7210         0               Horror Channel

Any assistance etc. gratefully received.

      0  1  3  4   0  1  3  4   0  1  3  4   0  1  3  4
DD HH 0  5  0  5   0  5  0  5   0  5  0  5   0  5  0  5
17 12:............ ....-------- ------------ ------------
17 16:------------ --.......... ............ ............
17 20:............ ------------ 77777777777- -7777777----

18 00:777777------ ------------ ------------ ------------

. No recording, - <7 recordings

[Graham]

Here's an example that seems to show the same tuner allocated to two recordings:

Yep ... NextPVR does that ... DVB-T broadcasts multiple channels on a single frequency/mux ... NextPVR is able to record all of the channels on one frequency using a single tuner.

With six tuners ... you can probably record twenty or more channels simultaeously.

You might want to say why you are recording more than a 1,000 movies ... we don't want anyone (e.g. me) wondering if you are  within the terms of the NextPVR software licence ... or not.

Edit: Intermittant glitches in a recording are usually due to signal quality issues ... What happens if you test by removing all splitters and coax extension cables?

[pabaxt]

Hi Graham, thanks for replying. I hadn't considered that the tuners would be able to stream multiple channels from the same multiplex / NPVR decode a multiplex stream. I'm very impressed!

I'll take a look at the T&Cs and ensure I'm in compliance. Must admit I've been like a kid in a sweet shop when I realised how much good content is out there for free. It's all purely for personal consumption.

Point taken about signal quality. No splitters/extensions but I plan some mitigations to improve the signal to the USB stick which is currently connected to the sat side of a uhf/sat splitter fed from a lofbox which is fed from a good quality roof ariel with line of sight to a main transmitter.

Thanks again for your helpful input.

[pabaxt]

I just tried an experiment. I set two channels on the same multiplex to record and NextPVR used two tuners in my HDHomeRun network box, so does the ability of NextPvr to record multiple streams for the same multiplex depend on the device? Device 27 highlighted above is the Hauppage USB stick, which is my lowest priority device.

[Graham]

I just tried an experiment. I set two channels on the same multiplex to record and NextPVR used two tuners in my HDHomeRun network box, so does the ability of NextPvr to record multiple streams for the same multiplex depend on the device? Device 27 highlighted above is the Hauppage USB stick, which is my lowest priority device.

There are a gazillion posts in this forum ... dating back eons ... that discuss the NextPVR scheduling algorithm.

Simply stated ... NextPVR tries to cater for every possible eventiuality (or all the possibilities that Sub dreamt up) ... For example ... Did NextPVR do what it did because, this evening, you might start a "Quick Record" a few moments before a show starts ... or, perhaps, to allow for a quick channel change when watching Live TV ... and so on and on.

Also simply stated ... all digital tuners are equal and should multi-record ... That said ... I have a vague memory that HDHR devices are more equal than others and special circumstances might apply ... something to do with whether the HDHR is using BDA drivers or http transfers (but I may have rememebered this all wrong).

Edit: Did you do an EPG Update after scheduling your recordings? NextPVR has (kind of) two scheduling algorithms ... It does a full re-schedule at the end of an EPG update ... It does a (kind of) "bung it on any tuner" at the time that you first request the recording.

[pabaxt]

Hi Graham, thanks again. No, I just picked BBC1 & 2 (SD on BBCA) off the Guide and set them to record the currently showing programmes, so I guess its not a fair experiment. I'll try to schedule a couple of programmes tomorrow after an overnight EPG update (Schedules Direct) and see what I get.

[mvallevand]

The HDHR modes that use http (and likely legacy rdp) won't multirec muxes but will multirec the same channel. I think BDA mode does.

Martin

[Graham]

Hi Graham, thanks again. No, I just picked BBC1 & 2 (SD on BBCA) off the Guide and set them to record the currently showing programmes, so I guess its not a fair experiment. I'll try to schedule a couple of programmes tomorrow after an overnight EPG update (Schedules Direct) and see what I get.

NextPVR runs its recording scheduling process at the end of the EPG update (both automatic and manual EPG updaes) ... All requested recordings are allocated to tuners as part of the recording scheduling process at the end of the EPG update.  Any recordings that you set/request during the day tomorrow will not be scheduled "properly" until the following EPG update.

The tuner allocations that are made by the recording scheduling process at the end of the EPG update will be changed (or added to) at the time that you set/request recordings during the day.

[sub]

The HDHR modes that use http (and likely legacy rdp) won't multirec muxes but will multirec the same channel.  I think BDA mode does.

This.

Usually when you're using HDHR device, it can only be tuned to a single channel at time. (listed as a 'HDHR' device on Settings->Devices page)

If you're on Windows, and using the SiliconDust BDA drivers, then it can record multiple channels on the same frequency. (listed as 'DVB-T' or 'DVB-C' on the Settings->Devices page)

[BrettB]

If you're on Windows, and using the SiliconDust BDA drivers, then it can record multiple channels on the same frequency. (listed as 'DVB-T' or 'DVB-C' on the Settings->Devices page)

Or as "ATSC" or "QAM" on the Settings->Devices page in other parts of the world.