No Surround Sound on ATSC 3.0 Channels

The Baltimore stations were just updated to ATSC 3.0. When using the Channels DVR beta or current release on the Apple TV 4K (2017), I do not get surround sound on the ATSC 3.0 stations. I get surround sound fine to the same stations when using the Channels app on the Fire TV Stick. I also get surround sound to the same stations when using the HDHomerun app on the same Apple TV. Setting the audio format on the Apple TV to Dolby Digital 5.1 does not fix the issue. Also, the problem occurs with or without turn sharing enabled. I have tried the default and the experimental video driver. Any ideas?

Are you getting sound at all? How are you checking if it is surround or not?

Yes. I get sound. I can tell its not surround because I do not get sound from the center speaker.

Please select record on the ATSC3 channel, wait one minute, stop the recording, then email the mpg file to [email protected]

Also in the app after not hearing center channel click Settings > Support > Submit Diagnostics

Done.

Thanks

Correction. I'm not getting surround on the Fire Stick app either. However, I do through the HDhomerun app.

There is no surround sound on my Pittsburgh ABC affiliate WTAE. Stats show 6 channel but only getting stereo sound.

Thats probably your local station. Here in Baltimore/DC area. The DC stations have it. The Baltimore stations don't even though the stats show the six channels.

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Just to follow up on this, I checked with the company who handled the setup of the Pittsburgh ATSC 3.0 stations, Bitpath, and they confirmed they're transmitting AC-4 in full 5.1.

I also sent 30 second recordings of the ATSC 3.0 channels to the Channels devs for them to investigate and they came back and said the stereo being delivered by Channels is the best they can do now.

So it looks like there are limitations with the AC-4 decoding within Channels.

That is why the sound is so weak in Channels.

The sound is not weak on ATSC 3.0 using Channels on Nvidia Shield. It's just only coming out of the left front and right front speakers.

Yet they have no problem decoding the full 5.1 audio from the AC-4 transmission of the Washington, DC ATSC 3.0 stations.

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The Channels devs indicated that it's being done differently in different markets. There's no standard so consider yourself lucky.

I can receive two different markets from my location: Washington, DC and Baltimore. Baltimore launched first around June of '21. DC followed about six months later. When Baltimore first launched, I was never able to get 5.1 audio despite both my receiver and Channels reporting 6 channel AC-4 audio. The DC stations had 5.1 audio on day one and also reported as such. Since I was able to get 5.1 audio from the DC stations, I assumed there was just an ongoing issue in Baltimore. I recently purchased a new Sony Bravia TV which just happens to have an ATSC 3.0 tuner. To my surprise, all the Baltimore stations that do not have 5.1 audio through Channels have 5.1 audio when watched through the Bravia. So it looks like the issue may be specific to Channels and/or HDHomeRun devices. One more item of information, the Baltimore stations were setup by Bitpath, the same company mentioned in the Pittsburg rollout.