ATSC 3.0 Portland - 2020

ATSC 3.0 Forum
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HTBruceM
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by HTBruceM »

NedS wrote: Tue Oct 20, 2020 7:39 pm That's one of the things we're looking into. If a device cannot decode AC-4, that it would automatically fallback to the ATSC 1.0 tuner.
How about using a trailing 0 on the virtual subchannel in the channel list for the ATSC3 tuner?
That way, the user can make a choice which tuner to use via the guide.
For example:
8.1 = use any of the available ATSC1 tuners for virtual 8.1
8.10 = use any of the available ATSC3 tuners for virtual 8.1

It would make it somewhat easier for users to choose the desired tuner type directly from the normal guide menu, rather than using command line methods.

ejohannes
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by ejohannes »

There has been lots of discussion the lack of AC-4 audio streams in many apps, which helps explain why VLC plays video fine but there is no audio.
But does this also explain why the HDHomeRun app on my PC, Mac and Firestick don't even play the video? On my PC it might play the video in a choppy manner for a second or two before freezing up completely.

Another question I have about all this is that is there only this single AC-4 audio track in these broadcasts?

methnen
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by methnen »

ejohannes wrote: Thu Oct 22, 2020 10:07 am There has been lots of discussion the lack of AC-4 audio streams in many apps, which helps explain why VLC plays video fine but there is no audio.
But does this also explain why the HDHomeRun app on my PC, Mac and Firestick don't even play the video? On my PC it might play the video in a choppy manner for a second or two before freezing up completely.
True. And like you with the latest 20201021b I'm still just getting choppy playback whenever I can get any play back at all and just blank screens from the HDHomeRun apps.

Trip
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by Trip »

HTBruceM wrote: Thu Oct 22, 2020 9:46 am How about using a trailing 0 on the virtual subchannel in the channel list for the ATSC3 tuner?
That way, the user can make a choice which tuner to use via the guide.
For example:
8.1 = use any of the available ATSC1 tuners for virtual 8.1
8.10 = use any of the available ATSC3 tuners for virtual 8.1

It would make it somewhat easier for users to choose the desired tuner type directly from the normal guide menu, rather than using command line methods.
The problem with this idea is that there are stations out there with virtual channels above xx.9.

- Trip

jakep82
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by jakep82 »

I'm already showing 8.10 in a recent scan on my Quatro. It's listed as KGWZLD.

ejohannes
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by ejohannes »

Trip wrote: Thu Oct 22, 2020 11:25 am
HTBruceM wrote: Thu Oct 22, 2020 9:46 am How about using a trailing 0 on the virtual subchannel in the channel list for the ATSC3 tuner?
That way, the user can make a choice which tuner to use via the guide.
For example:
8.1 = use any of the available ATSC1 tuners for virtual 8.1
8.10 = use any of the available ATSC3 tuners for virtual 8.1

It would make it somewhat easier for users to choose the desired tuner type directly from the normal guide menu, rather than using command line methods.
The problem with this idea is that there are stations out there with virtual channels above xx.9.

- Trip
This may not be a perfect solution, but perhaps it could be made an optional mode and a configurable parameter:
The user can turn on the separate ATSC1.0/3.0 into separate channel registrations with a configurable number parameter that appends to the end of the minor number. Thus I could set this to be say 7 and then I would end up with channel 10.1 for the ATSC1.0 and 10.17 for ATSC3.0 (or visa-versa with the 3.0 being on 10.1 and 1.0 being on 10.7). This would allow users in the various markets to tailor the settings work for their area.
Clearly there may be markets that this approach may still have collisions, but for probably 98% of the markets right now this would work. In the future once everything works for everybody this feature could be removed.

kyl416
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by kyl416 »

Or they could just finally implement a way to support duplicate major-minor numbers since this has been an ongoing issue long before ATSC 3.0 was a thing, especially in areas served by translators or people living in bordering counties where they can pick up multiple neighboring DMAs.

If the thing holding it up is how to handle the URLs, maybe they should start including the RF number as part of the URL. Like if you're in an area of eastern PA or central New Jersey that gets 2.1 WDPN on RF 2 from Philly, 2.1 WCBS on RF 36 from NYC, 4.1 WACP on RF 4 from Atlantic City and 4.1 WNBC on RF 35 from NYC, they can attempt to support both by using URLs like this:
http://ipaddress:5004/auto/r2v2.1 for WDPN
http://ipaddress:5004/auto/r36v2.1 for WCBS
http://ipaddress:5004/auto/r4v4.1 for WACP
http://ipaddress:5004/auto/r35v4.1 for WNBC
http://ipaddress:5004/auto/r22v2.1 for people on Long Island who can get WCBS's RF 22 translator


There's a similar issue that someone from the UK posted where they get multiple BBC and ITV regions over the air because they border a region, but since the Freeview system has a uniform lineup, BBC One is on channel 1 and ITV is on channel 3 on all lineups so the duplicates are hidden, leaving them no way to view their preferred region for local news.

HTBruceM
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by HTBruceM »

In Portland we have KGW (NBC) doing local broadcasting:
Virtual 8.1, 8.2, 8.3 for ATSC1 on VHF channel 8 subchannel 1-3.
Virtual 8.1, 8.2, 8.3 for ATSC3 on UHF channel 30 subchannel 1-3.
The problem is, both channels map back to the same 8.1 - 8.3. There are probably ways to deal with this, with some creative thinking. They're both going to live side by side for some time so something needs to be figured out. Of course all this might conflict with some standards somewhere that define the rules for virtual channel numbering., but what about these ideas:

1: Create another set/sequence of higher numbers for all the ATSC3 broadcasts, and somehow incorporate the virtual mapping into it. Like add 100 to all the virtual channels.
Code could look for a number >99 and that would mean it's ATSC3, just subtract 100 to get back to the virtual channel for guide data. No linkage to the RF channel though.
Example:
Virtual 8.1, 8.2, 8.3 for ATSC1
Virtual 108.1, 108.2, 108.3 for ATSC3

2: If additional delimiters can be used that might be even simpler. Append the RF channel being used. Channel ID parsing could just "lop off" characters starting with the 2nd delimiter "." in the sequence, to map back to the original virtual channel. Any channel with the 2nd "." delimiter in the virtual channel is an ATSC3 channel, and guide data can be mapped back to their 8.1, 8.2, 8.3 counterparts.
Example:
Virtual 8.1, 8.2, 8.3 for ATSC1
Virtual 8.1.30, 8.2.30, 8.3.30 for ATSC3 on RF30

jasonl
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by jasonl »

kyl416 wrote: Thu Oct 22, 2020 12:20 pm There's a similar issue that someone from the UK posted where they get multiple BBC and ITV regions over the air because they border a region, but since the Freeview system has a uniform lineup, BBC One is on channel 1 and ITV is on channel 3 on all lineups so the duplicates are hidden, leaving them no way to view their preferred region for local news.
The UK actually has a proper fix for this in that the transmitters in each region broadcast and identifier with the name of the region, and receivers are intended to give users an option to select their preferred region when multiple are present. SD has known about this for a long time but it apparently has never gotten high enough up the priority list. My guess is that it's because British culture is to suffer in silence rather than complain long and loud about things the way we Americans do :lol:.

Fixing duplicate handling in the US in a predictable way is a much bigger challenge, especially if the goal is to not break a dozen different applications that have built-in assumptions about how channel numbering is done. Adding 100 to ATSC 3 channels is one thought, but has anyone reviewed the ATSC 3 standard to make sure it doesn't allow channel numbers over 100? We know that channels over 69 aren't used in the US, but we aren't the only country using it now, and more will follow.

NedS
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by NedS »

HTBruceM wrote: Thu Oct 22, 2020 9:46 am
NedS wrote: Tue Oct 20, 2020 7:39 pm That's one of the things we're looking into. If a device cannot decode AC-4, that it would automatically fallback to the ATSC 1.0 tuner.
How about using a trailing 0 on the virtual subchannel in the channel list for the ATSC3 tuner?
That way, the user can make a choice which tuner to use via the guide.
For example:
8.1 = use any of the available ATSC1 tuners for virtual 8.1
8.10 = use any of the available ATSC3 tuners for virtual 8.1

It would make it somewhat easier for users to choose the desired tuner type directly from the normal guide menu, rather than using command line methods.
That violates the ATSC specs. Even in ATSC 1.0, there are .10 and higher numbered sub-channels. With ATSC 3.0 it wouldn't be crazy to see 20 or more sub-channels on a single transmitter.

NedS
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by NedS »

kyl416 wrote: Thu Oct 22, 2020 12:20 pm Or they could just finally implement a way to support duplicate major-minor numbers since this has been an ongoing issue long before ATSC 3.0 was a thing, especially in areas served by translators or people living in bordering counties where they can pick up multiple neighboring DMAs.
Dealing with these ATSC 3.0 issues will likely result in finally tackling these other situations as well.

robbadler
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by robbadler »

When I use chrome on my Mac or Android phone to record KGW http://192.168.1.15:5004/auto/v8.1?duration=30 I am still not seeing any audio stream in the capture. Is this a regional in issue, or something I'm doing wrong?

NedS
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by NedS »

robbadler wrote: Thu Oct 22, 2020 7:34 pm When I use chrome on my Mac or Android phone to record KGW http://192.168.1.15:5004/auto/v8.1?duration=30 I am still not seeing any audio stream in the capture. Is this a regional in issue, or something I'm doing wrong?
I don't know if there's any Mac software that is playing back AC-4 yet. There should be an update for the HDHomeRun app for Android that should make audio work on most recent Android hardware, and that should be out in the Google Play store shortly.

robbadler
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by robbadler »

NedS wrote: Thu Oct 22, 2020 9:32 pm
robbadler wrote: Thu Oct 22, 2020 7:34 pm When I use chrome on my Mac or Android phone to record KGW http://192.168.1.15:5004/auto/v8.1?duration=30 I am still not seeing any audio stream in the capture. Is this a regional in issue, or something I'm doing wrong?
I don't know if there's any Mac software that is playing back AC-4 yet. There should be an update for the HDHomeRun app for Android that should make audio work on most recent Android hardware, and that should be out in the Google Play store shortly.
I wasn't trying to play it on mac. I was using ffmpeg to inspect the streams, and don't see an audio stream.

As for the HDHomeRun app, I'm in the beta program, running v20201022, and while three video of much smoother, there is no audio on my OnePlus8, running Android 10.5.

kyl416
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by kyl416 »

robbadler wrote: Fri Oct 23, 2020 12:42 pm I wasn't trying to play it on mac. I was using ffmpeg to inspect the streams, and don't see an audio stream.
FFmpeg can't detect the audio stream because there's no open source AC-4 codec available. There's an open ticket about it:
https://trac.ffmpeg.org/ticket/8349

This also affects other FFmpeg based platforms like VLC, Kodi and Plex.

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