Multi record

ATSC 3.0 Forum
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therealmatey
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Multi record

Post by therealmatey »

On the Kickstarter FAQ it indicated that 2 ATSC 3.0 tuners would be sufficient due to the deployments in a given city sharing the same frequency. So, this suggests that we should be able to tune more than 2 channels simultaneously. NextPVR calls this multi record.

However, I have tried to record more than two ATSC 3.0 channels simultaneously without success. The 3rd and 4th get an error that the channel cannot be locked. The transmitter I’m accessing is in Buffalo, NY which definitely has all 5 ATSC 3.0 channels on the one frequency, and each tunes fine individually, or two at once.

So, is it possible to tune 4 ATSC 3.0 channels simultaneously that share the same frequency? If so, is there some trick to get this working? I would guess the HDHomeRun would use the 3rd and 4th “tuners” to tune the additional channels, or it might use some smarts that allow it to “multi record.”

If it helps any, I’m using NextPVR 5.1.1 on windows 10.

Thanks

FoodLioon
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Re: Multi record

Post by FoodLioon »

You have to use the ATSC protocol in NextPVR for multirec to work. If you are using the HDHR protocol, it won't work. Multirec also only works on Windows. The ATSC protocol in NextPVR has it's own scan, it doesn't rely on the HDHomeRun scan. I also set the compatibility mode to NextPVR in the HDHomeRun setup when using NextPVR.

I have no idea of the status of ATSC 3.0 in NextPVR. That would be a question for the developer.

jsmar
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Joined: Wed Aug 13, 2008 1:06 am

Re: Multi record

Post by jsmar »

Since the ATSC3.0 format is completely different from ATSC1.0, it's doubtful that developer has already added support for ATSC3.0 Multirec on NextPVR. Note that in order to do that development the author would have to have a developer mode version of the HDHR5-4K. Finally, at least currently (this is kind of a current pet peeve of mine, because who wants to develop only for other developers), if the author does add Multirec support for ATSC3.0 on NextPVR, it would only work for those with the developer version of the HDHR5-4K. This is because the only way it could be done is by parsing a full mux raw ALP packet capture of the physical channel, which can only be done on the developer version.

timeshifter
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Re: Multi record

Post by timeshifter »

I've seen this topic of being able to tune more than one virtual channel on the same RF channel from a single tuner come up before, but can't remember if there was an official position on it from SD. Is this a feature that could be made generally available with a firmware update to the HDHR5-4K? Or, is there more to it than that?

FoodLioon
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Re: Multi record

Post by FoodLioon »

timeshifter wrote: Fri Apr 23, 2021 7:47 am I've seen this topic of being able to tune more than one virtual channel on the same RF channel from a single tuner come up before, but can't remember if there was an official position on it from SD. Is this a feature that could be made generally available with a firmware update to the HDHR5-4K? Or, is there more to it than that?
It's a software issue. You need both the SiliconDust driver and DVR software to support it.
When NextPVR is using the HDHomeRun ATSC driver, the entire stream is coming over the network and can record whatever channels are in that stream. The SiliconDust DVR engine just sends one channel over the network.

signcarver
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Re: Multi record

Post by signcarver »

Not for what is being asked about here as it is to be done by the tuner and the software wouldn't even be aware of such. The idea is that when one requests http://<tunerid>:5004/auto/v5.1 and http://<tunerid>:5004/auto/v12.1 that a single 3.0 tuner would be used (if on same physical channel/plp) that way a single device can still tune 4 atsc 3.0 channels though it has only 2 atsc 3.0 tuners and as presented in the KS a feature would be added in that the device would use the same tuner to make separate channels available. Keep in mind that atsc 3.0 is a different beast compared to what 1.0 is.

One issue is that here in Phoenix one would need 3 ATSC 3.0 tuners to get any combination of 4 tuners as 27 can't have it's 4 channels tuned by 1 tuner as the plp's can't be simultaneously tuned by one tuner while 35 all the channels can in theory be tuned at once.

However from the topic name, as well as dealing with NextPVR which may or may not be using "auto", I can understand the confusion as it wouldn't be really considered "Multi Record" but rather "Multi Tune???" or some such.

FoodLioon
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Re: Multi record

Post by FoodLioon »

That's a bummer if you need the developer edition to get the entire 3.0 stream over the network. I have some tuners on NextPVR just for the multirec feature.

therealmatey
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Re: Multi record

Post by therealmatey »

Interesting. It would be good to get a response from SD that elaborates on what they were suggesting in the FAQ as I interpret the statement to mean that this should work under the native device they’ve provided. It was the reason for providing tATSC 3.0 on only 2 tuners.

NedS
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Re: Multi record

Post by NedS »

The plan is to eventually have some kind of multi-channel (2x) access from a single 3.0 tuner for all ATSC 3.0 HDHR models, not just the dev models.

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