AC-4 Audio?

ATSC 3.0 Forum
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nickk
Silicondust
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Re: AC-4 Audio?

Post by nickk »

We found and fixed a problem that was preventing AC4 audio from working on ARM based platforms that support AC4 audio.

There will be Android, iOS, and AppleTV app releases in the next few days.

Nick

bgrubb1
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Re: AC-4 Audio?

Post by bgrubb1 »

Thank you sir for the information :-)

darcilicious
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Re: AC-4 Audio?

Post by darcilicious »

Yay!

chris_in_texas
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Re: AC-4 Audio?

Post by chris_in_texas »

Any word on the ATSC1 / ATSC3 switch that can be flipped on a per channel basis? For now I would like to remove ATSC3 until the AC4 addition is done. I can still use it as an ATSC1 tuner for Plex until something happens there.

darcilicious
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Re: AC-4 Audio?

Post by darcilicious »

Yes, either in this thread or in a related audio thread SiliconDust says there’s a update coming very soon. It will require both a firmware and an application update. I am assuming this means an update to the API so that third-party software can also do the right thing.

nickk
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Re: AC-4 Audio?

Post by nickk »

iOS and AppleTV app updates released.

The AppleTV app also improves MPEG2 picture quality on the AppleTV 4K.

Nick

darcilicious
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Re: AC-4 Audio?

Post by darcilicious »

nickk wrote: Fri Dec 04, 2020 5:11 pm iOS and AppleTV app updates released.

The AppleTV app also improves MPEG2 picture quality on the AppleTV 4K.

Nick
Getting audio on all seven ATSC 3.0 channels in Portland on the Apple TV 4K (version 20201204 (App)/20201204 (UI)).

Thank you!

bgrubb1
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Re: AC-4 Audio?

Post by bgrubb1 »

two versions ago of the AppleTV app two channels in the phoenix area were blocky green. In the previous version video was fine but no audio on 15.1 With this new version the green blocky is back but there is audio. Do I have a setting wrong ?? I am in SDR mode
Thank you for any help
...Barry

talkenrain
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Re: AC-4 Audio?

Post by talkenrain »

nickk wrote: Thu Dec 03, 2020 7:12 pm We found and fixed a problem that was preventing AC4 audio from working on ARM based platforms that support AC4 audio.

There will be Android, iOS, and AppleTV app releases in the next few days.

Nick
My experience using release 20201204 on AppleTV 4k:
The audio is much improved but still nowhere near what it should be. Im in the Portland market. Audio seems to be off center (ABC, CBS channels; left audio dominates, NBC channel; the right audio dominates, All channels, the audio fidelity is not what it should be.

I also have an LG OLED with the HD app running on it. Using the same audio gear while watching/listening the same channels, The audio from the LG is 1000% better, no balance issues and really preforms great compared to the same app on the AppleTV.

darcilicious
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Re: AC-4 Audio?

Post by darcilicious »

talkenrain wrote: Fri Dec 04, 2020 7:45 pm My experience using release 20201204 on AppleTV 4k:
The audio is much improved but still nowhere near what it should be. Im in the Portland market. Audio seems to be off center (ABC, CBS channels; left audio dominates, NBC channel; the right audio dominates, All channels, the audio fidelity is not what it should be.
Thanks for posting this, I didn't have the patience for determining detailed audio issues tonight :)

NedS
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Re: AC-4 Audio?

Post by NedS »

talkenrain wrote: Fri Dec 04, 2020 7:45 pm
nickk wrote: Thu Dec 03, 2020 7:12 pm We found and fixed a problem that was preventing AC4 audio from working on ARM based platforms that support AC4 audio.

There will be Android, iOS, and AppleTV app releases in the next few days.

Nick
My experience using release 20201204 on AppleTV 4k:
The audio is much improved but still nowhere near what it should be. Im in the Portland market. Audio seems to be off center (ABC, CBS channels; left audio dominates, NBC channel; the right audio dominates, All channels, the audio fidelity is not what it should be.

I also have an LG OLED with the HD app running on it. Using the same audio gear while watching/listening the same channels, The audio from the LG is 1000% better, no balance issues and really preforms great compared to the same app on the AppleTV.
That sounds like a channel mapping issue (what tracks are going to what speakers), which should be fairly easy to correct. The important part is that audio is working at all (which means the AC-4 decoding is working). We will have the dev team look into the audio mapping and try to get that fixed ASAP.

talkenrain
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Re: AC-4 Audio?

Post by talkenrain »

NedS wrote: Fri Dec 04, 2020 9:00 pm
talkenrain wrote: Fri Dec 04, 2020 7:45 pm
nickk wrote: Thu Dec 03, 2020 7:12 pm We found and fixed a problem that was preventing AC4 audio from working on ARM based platforms that support AC4 audio.

There will be Android, iOS, and AppleTV app releases in the next few days.

Nick
My experience using release 20201204 on AppleTV 4k:
The audio is much improved but still nowhere near what it should be. Im in the Portland market. Audio seems to be off center (ABC, CBS channels; left audio dominates, NBC channel; the right audio dominates, All channels, the audio fidelity is not what it should be.

I also have an LG OLED with the HD app running on it. Using the same audio gear while watching/listening the same channels, The audio from the LG is 1000% better, no balance issues and really preforms great compared to the same app on the AppleTV.
That sounds like a channel mapping issue (what tracks are going to what speakers), which should be fairly easy to correct. The important part is that audio is working at all (which means the AC-4 decoding is working). We will have the dev team look into the audio mapping and try to get that fixed ASAP.
A little more info... After more checking I see the output from the AppleTV to my AV preamp is PCM but the output of the LG to the same AV preamp is DolbyDigital 5.1

ppasteur
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Re: AC-4 Audio?

Post by ppasteur »

ATV always sends out PCM, for everything, always. It decodes all formats internally. It cannot "bitstream" audio.
Not that this is the cause of the problem, but it does determine what your AVR will display.

talkenrain
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Re: AC-4 Audio?

Post by talkenrain »

ppasteur wrote: Sat Dec 05, 2020 1:30 pm ATV always sends out PCM, for everything, always. It decodes all formats internally. It cannot "bitstream" audio.
Not that this is the cause of the problem, but it does determine what your AVR will display.
You are correct I just wanted to provide all the info I could.

Just to share my experience on various platforms and apps. Here is a little more feedback for the team working on issues.

My test case:
Portland market, tested on several local ATSC 3.0 stations (strong RF signal). Using only tuners 0 or 1. HDHR5-4K Firmware 20201030. All ethernet connected.

AppleTV 4k:
Using Channels app 4.3.1 - Choppy video/audio, one sided audio - Not usable.
Using HDHomeRun app 20201204 - Video good, audio one sided, low fidelity - Usable.

Nvidia Shield Pro:
Using Channels app 3.0.2 - Choppy video/audio, one sided, low fidelity - Not usable.
Using HDHomeRun app 20201113 - Choppy video/audio, one sided, low fidelity - Not usable.

LG OLED TV:
Using HDHomeRun app 20200923 - Excellent video, absolutely awesome audio on all channels.

By the way, to the SD team, thank you for the attention and progress you've made. I'm excited for the day when it's all up and running perfectly. I have confidence that day will come before I get a covid vaccine. ;)

dwaleke
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Re: AC-4 Audio?

Post by dwaleke »

I can also confirm that audio channel mapping appears to be incorrect on AppleTV 4k.

Center channel seems to be coming out of the right channel.

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