ATSC 3.0 Portland - 2020

ATSC 3.0 Forum
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kyl416
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by kyl416 »

Lost Dog wrote: Mon Oct 19, 2020 2:24 pmUsing the VLC network stream http://192.150.45.16:5004/auto/v8.1 it seems to tune in the ATSC3 option for 8.1:

How do you manually tune the ATSC1 8.1 option?

Thanks!
Try http://192.150.45.16:5004/tuner2/v8.1 or http://192.150.45.16:5004/tuner3/v8.1

signcarver
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by signcarver »

That won't work (usually) if 8.1 was detected as an ATSC 3.0 stream as it added the other location for the virtual channel numbers. The way I usually do it is to tune by physical channel

http://<ip-of-tuner>:5004/auto/ch# where # is the physical channel number and then in vlc choose playback, program, and choose which stream from that channel you want

Ken.F recently posted a way to get to the program number directly at viewtopic.php?p=361773#p361773 but I haven't been too successful with such (I get more success using a - rather than : but make sure you use the true physical sub channel number not the virtual sub channel number).

jakep82
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by jakep82 »

I just installed the Channels beta that was released today, and audio on ATSC 3.0 channels is now working properly on my Chromecast with Google TV. I'll need to do more testing, but so far it looks good.

codezilla
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by codezilla »

I'm not getting any audio on HEVC channels. For example with KGW, If I tune to channel 8.10 I get an MPEG2 stream with audio that plays perfectly in VLC. At this moment, the stream is broadcasting 7 PID's, consisting of 1 video, 2 audio, and 4 subtitles. If I tune to channel 8.1 (instead of 8.10) I get an HEVC video stream, with no audio. At this moment, I'm getting 5 PID's consisting of 1 video and 4 subtitles. I get the same situation on every HEVC channel. When I load the streams in TSReader, I'm seeing the same PID's, and I get the same playback on the ROKU app. My signal levels on this tuner are: Signal Strength 86%, Signal Quality 91%, Symbol Quality 100%. Is this a signal issue where I should replace/reposition my antenna? I am on firmware 20201018. Hopefully someone can help.

darcilicious
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by darcilicious »

codezilla wrote: Mon Oct 19, 2020 9:21 pm I get the same situation on every HEVC channel. When I load the streams in TSReader, I'm seeing the same PID's, and I get the same playback on the ROKU app.
The HEVC channels are broadcasting ac-4 audio, which most platforms do not support. See viewtopic.php?f=133&t=74253 for info.

codezilla
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by codezilla »

After posting this I had ran a few more channel scans. Now I'm only getting HEVC versions of channels 2, 6 and 12. I cannot get the regular mpeg2 versions. When I run another scan, the channels pop up in the list, then disappear upon completion. Am I now required to tune these channels using frequencies as discussed earlier in this thread?

robbadler
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by robbadler »

I'm using a OnePlus 8 which claims to support AC4. I captured a 30 second clip via the direct url to tuner0, and there was no audio from any HEVC stream

jakep82
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by jakep82 »

I can confirm that audio is working both through the HDHR app on my LG CX, and through the Channels beta app on my Chromecast with Android TV. Audio does not work when playing HEVC recordings on my Pixel 3a. I haven't checked to see if my phone is supposed to support AC-4.

methnen
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by methnen »

If it's true that AC-4 audio is the issue and there's devices that don't support it there should really be some sort of intelligent fall back shouldn't there?

Or at the very least a way to tell the device to only serve up the older version of the stream on a per channel basis maybe?

NedS
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by NedS »

methnen wrote: Tue Oct 20, 2020 4:59 pm If it's true that AC-4 audio is the issue and there's devices that don't support it there should really be some sort of intelligent fall back shouldn't there?

Or at the very least a way to tell the device to only serve up the older version of the stream on a per channel basis maybe?
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.

HTBruceM
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by HTBruceM »

Regarding the lack of AC-4 capable playback devices....

Fallback to one of the ATSC1 tuners is going to kick out a bunch of your Kickstarter beta testers, will it not?

For those of us using Plex clients... My hope is that (someday) our Plex server will transcode the AC-4 audio to AC-3 or some other audio stream compatible with the myriad of Plex client hardware. Any chance you guys have an engineering pipeline with the Plex team to see if/when the AC-4 transcoding is coming? I for one, have been hoping to "standardize" on the Plex client environment. It works very well today with the HdHomeRun Extend.

Does the ATSC3 standard allow for multiple audio streams? If so, it would be really nice if broadcasters would include an AC-3 stream in addition to the AC-4 stream... Then at least you guys could build in some code to fallback to the AC-3 stream.

jakep82
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by jakep82 »

NedS wrote: Tue Oct 20, 2020 7:39 pm
methnen wrote: Tue Oct 20, 2020 4:59 pm If it's true that AC-4 audio is the issue and there's devices that don't support it there should really be some sort of intelligent fall back shouldn't there?

Or at the very least a way to tell the device to only serve up the older version of the stream on a per channel basis maybe?
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.
This will require some care in implementation. My Channels DVR server is a mini PC running Ubuntu, and it definitely can't decode AC-4, but my client is a Chromecast that can decode AC-4. Once things have settled and bugs have been worked out, I would prefer everything to record in HEVC.

kyl416
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by kyl416 »

HTBruceM wrote: Tue Oct 20, 2020 10:46 pmAny chance you guys have an engineering pipeline with the Plex team to see if/when the AC-4 transcoding is coming?
The big problem is there's no open source AC-4 codec right now, which prevents FFmpeg based platforms like VLC, Kodi and Plex from decoding it. FFmpeg already has an enhancement ticket about it, but no progress has been made in the past year.

Maybe now that ATSC 3.0 is finally being deployed some of FFmpeg's developers might take a bigger interest in attempting to support it, but considering that most of the world uses the DVB-T2 standard for their "next gen" terrestrial TV, and AC-4 isn't part of that spec like it is for ATSC 3.0, it might not be a priority for their non-US developers.

krv
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by krv »

kyl416 wrote: Wed Oct 21, 2020 12:12 am
HTBruceM wrote: Tue Oct 20, 2020 10:46 pmAny chance you guys have an engineering pipeline with the Plex team to see if/when the AC-4 transcoding is coming?
The big problem is there's no open source AC-4 codec right now, which prevents FFmpeg based platforms like VLC, Kodi and Plex from decoding it. FFmpeg already has an enhancement ticket about it, but no progress has been made in the past year.

Maybe now that ATSC 3.0 is finally being deployed some of FFmpeg's developers might take a bigger interest in attempting to support it, but considering that most of the world uses the DVB-T2 standard for their "next gen" terrestrial TV, and AC-4 isn't part of that spec like it is for ATSC 3.0, it might not be a priority for their non-US developers.
It is true that the key to getting a lot software working with ac-4 hinges on FFmpeg. The enhancement ticket is currently marked as PRIORITY: WISH. if enough people logon to the ffmpeg forum and up-vote the ticket it might get some traction, but currently it only has two votes.

HTBruceM
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Re: ATSC 3.0 Portland: QUATRO 4K

Post by HTBruceM »

Well $hit

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