HDHomeRun new 4K ATSC 3.0 tuner

Just received an email about their new 4 channel tunner:

Will this eventually be supported with Channels DVR?

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It already is! From the Kickstarter page:


3rd Party Compatibility

For those of you with Plex, Channels, or any other 3rd party software - we are excited to say that 3rd party support will work the same way. The HDHomeRun QUATRO 4K outputs MPEG-TS streams so existing apps can record content without changes and can playback content with the addition of codec support.

You can't really say that is compatible. Only the devs of Channels can do that.
I wold think the ATSC 1.0 streams would work fine as they do now, buy u have no way of knowing how the Channels DVR and the client apps on the varying ecosystems will handle the 4K res and HEVC streams. Transcodeing 4K streams also will require much stronger sever hardware, so many lower end devices that folks run their server on may no longer be up compatable.

Second, the devs of Channels would need to get one of these to test to properly tweak and optimize their software for use with this new device. Which won't be for years.

Well, since the Channels clients handled the Verizon FiOS 4K streams fine, I doubt there will be much difference with ATSC3 4K. Also, all of the Channels clients use the same player backend, so worrying about which OS/platform video player will support the codecs isn't a concern, either.

This is awesome! I've been waiting for this to finally upgrade my 2013 duo, been wanting the extra tuners but have been holding out for 4k. It also helps that I'm in one of the early markets.

Follow @getchannels on Twitter:

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Should be interesting to see how Channels implements the (4) ATSC 1 tuners with (2) of them ATSC 3 that can potentially tune up to 4 channels on just those 2 tuners, to get the maximum usage out of them.

Had to read the tuner details a few times before I even understood how it worked.

Deployment map:

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Here's a brief tech demo of the card. He doesn't show a 4K video but does show a 1080P stream that's encoded in HEVC.

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I don't think it works like that. It is the same thing that OTA does now with subchannels. For example, an OTA ATSC stream has space for usually 1 HD channel and about 4 SD subchannels. Channels gets 1 station (the one you selected) when you tune it to that frequency, not all of them. ATSC 3.0 just adds a lot more compression to fit more than 1 HD channel on the frequency.

If you are going to tune watch or record two different stations on the same frequency, the HDHomeRun will use two tuners, just like it does now, with ATSC 1. So basically, you can do 2 ATSC 3.0 channels at the same time with two tuners.

From their kickstarter page:

We plan to enable multi-channel support so you can watch up to 4 ATSC 3.0 sub-channels across the 2 ATSC 3.0 tuners, all in high definition!

AFAIK all this stuff is going to be part of their firmware, so as far as Channels (or other software) is concerned we just ask the tuner to give us the stream for a specific channel and it figures out the rest.

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I don't think they described it well. They should have said, you can split each ATSC3 tuner into four sub-tuners to get other channels on the same frequency. These can all be watched at the same time, without using the ATSC1 tuners, which are still available to tune even more channels. This effectively makes it a 10-channel device.

I'm not sure that is what it is though. More likely, the ATSC3.0 tuner can tune one frequency and split it off to the remaining 3 tuners, as long as 2 of the subchannels are 8VSB.

What about signal loss with all that splits?

Once it makes it to the device, I don't think you have to worry about further signal loss. I think what they are saying is this:

  1. You can tune 4 channels at a time.... regardless of where they come from. But only 2 ATSC3 at a time.
  2. Although the ATSC1 tuners can't pick up the ATSC3 frequency, An ATSC3 tuner that can get it is able to send the ATSC1 subchannel to one of the ATSC1 tuners. Meaning that you can have an ATSC3 channel tuned and an ATSC1 subchannel on the same frequency tuned using a different tuner on the device.

Curious how Priority works then. Assuming Tuners 0 and 1 are first, that are 3.0, if u tune to 1.0 channel, will it then detect that and instead use tuner 3 instead.
And if u tune to a 3.0 station, then tuner 0 activates, but if another user tunes to that same station secondary channel frequency channel, then it activates the 1.0 tuner (2 or 3)? or is that saying that Tuner 0 can mutil stream both a 3.0 channel and a 1.0 channel and not use other tuners?

I don't know. What @tmm1 stated made it sound like the single tuner could split itself into subtuners without using any of the other 3 tuners. Which is exciting at first. But, somehow, I think they would have made it more clear and advertised the device as supporting 10 simultaneous channels if this was the case (it wouldn't be a Quatro anymore, it would be a HDHR Deco). I think it is still limited to the 4 tuners on the device, able to tune 4 channels. But all 4 can be from a single frequency ATSC3 stream, as long as 2 of the subchannels are 8VSB.

Sweet. Love it that you guys are already looking at this.

I believe this will technically be possible, but only when tuning for the physical channel and not filtering the stream. Unfortunately, this is not presently how Channels handles tuning devices that can accept the HTTP API (HDHR4 and newer).

As an example, say that you receive your NBC and its subchannels on 4.1, 4.2, and 4.3, and they are broadcast on UHF channel 32. The way Channels currently works is that each virtual channel is separately requested, and consumes a separate tuner. So, when you want 4.1, Channels asks the tuner for it, the tuner tunes physical channel 32, filters out all of the other subchannels, and delivers only 4.1. If you want to tune 4.3 on a different client concurrently, Channels makes a second request for 4.3, and it uses a second tuner on the device. (This is also how SiliconDust's software works.)

Another way of achieving this is that Channels would request the full physical channel 32 and receive that from the tuner. Then Channels asks the tuner to filter out unwanted subchannels, leaving only 4.1. Later if you additionally wanted to simultaneously view 4.3, Channels could change the filter to also include that subchannel. Channels would then handle distributing the filtered streams (a mixed stream with 2 muxes, which Channels then must separate and feed separately to the different clients). This is the way some other DVR software works, like Tvheadend.

ATSC3 allows for up to 4 subchannels on each physical channel. So, while technically Channels could handle the situation in the second manner described, it's unlikely that it will. The process will probably continue much as before, as in the first situation described.

(Bandwidth is also a concern. The HDHR5-4K will only have a 100Mbps adapter, while physical ATSC3 channels can have a maximum of 57Mbps. So, it's easy to see that by using the second scenario of having Channels filter the muxes could easily overwhelm its network adapter. ATSC1 has a maximum bandwidth of 19Mbps for each physical channel; this means that is all 4 tuners we're delivering full bandwidth channels, that would be just under 160Mbps.)

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um...what? why is it not 1gig NIC (1000Mbps) in it? it woudl need that for 4K streams and load of other streams. if each stream is up to 57Mbps