AC-4 Audio?

ATSC 3.0 Forum
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darcilicious
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Re: AC-4 Audio?

Post by darcilicious »

vanhln wrote: Sun Dec 27, 2020 5:48 pm Thanks.. I know the FFMpeg update is important also.. I do need more tuners so considering the connect 4k... Err by app awareness.. that prolly means Plex... I'm a patient man, so will still probably get the hardware at some point....
I'm not talking about the AC4/ffmpeg update; I'm assuming that there will need to be an update to Plex in order to tune the 1.0 channel once the 3.0 channels are broadcasting in your area, once SD has made the update to the firmware. I'm only basing that on what Nick posted previously, however...

vanhln
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Re: AC-4 Audio?

Post by vanhln »

ok.. thanks.

rainlake
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Re: AC-4 Audio?

Post by rainlake »

darcilicious wrote: Sun Dec 27, 2020 5:53 pm
vanhln wrote: Sun Dec 27, 2020 5:48 pm Thanks.. I know the FFMpeg update is important also.. I do need more tuners so considering the connect 4k... Err by app awareness.. that prolly means Plex... I'm a patient man, so will still probably get the hardware at some point....
I'm not talking about the AC4/ffmpeg update; I'm assuming that there will need to be an update to Plex in order to tune the 1.0 channel once the 3.0 channels are broadcasting in your area, once SD has made the update to the firmware. I'm only basing that on what Nick posted previously, however...
Nickk said they will move ATSC 3 to 100+ so plex should work without problem.

darcilicious
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Re: AC-4 Audio?

Post by darcilicious »

rainlake wrote: Sun Dec 27, 2020 7:38 pm
Nickk said they will move ATSC 3 to 100+ so plex should work without problem.
That'd be nice -- assuming what he originally said no longer applies :)

CBme
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Re: AC-4 Audio?

Post by CBme »

darcilicious wrote: Sun Dec 27, 2020 7:57 pm
rainlake wrote: Sun Dec 27, 2020 7:38 pm
Nickk said they will move ATSC 3 to 100+ so plex should work without problem.
That'd be nice -- assuming what he originally said no longer applies :)
Plex should work without issue with the workaround specified as it is simply additional channels, not some new way to select a channel and then select 1.0 or 3.0 that Plex wouldn't understand.
Plex likely won't be able to automatically map the atsc 3.0 100+ channels correctly but we should be able to do so manually as you can now (though you might need to drop the atsc 1.0 if you want to do that as you don't seem to be able to map two channels to the same guide channel). Of course it still won't play AC4 until FFMpeg gets updated.

viewtopic.php?f=133&t=74778
Tuning ATSC 1.0 vs 3.0 channels:
We have an ongoing effort to support multiple channels with the same virtual channel number to support user selection between ATSC 1.0 and ATSC 3.0. We want to get everyone up and running now so the pending firmware release has a short term workaround moving the ATSC 3.0 channels to 100+ channel numbers.
Last edited by CBme on Sun Dec 27, 2020 11:45 pm, edited 1 time in total.

darcilicious
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Re: AC-4 Audio?

Post by darcilicious »

CBme wrote: Sun Dec 27, 2020 10:54 pm
darcilicious wrote: Sun Dec 27, 2020 7:57 pm
rainlake wrote: Sun Dec 27, 2020 7:38 pm
Nickk said they will move ATSC 3 to 100+ so plex should work without problem.
That'd be nice -- assuming what he originally said no longer applies :)
viewtopic.php?f=133&t=74778
Tuning ATSC 1.0 vs 3.0 channels:
We have an ongoing effort to support multiple channels with the same virtual channel number to support user selection between ATSC 1.0 and ATSC 3.0. We want to get everyone up and running now so the pending firmware release has a short term workaround moving the ATSC 3.0 channels to 100+ channel numbers.
Also posted previously:
nickk wrote: Wed Dec 02, 2020 8:44 pm
darcilicious wrote: Wed Dec 02, 2020 8:05 pm
nickk wrote: Wed Dec 02, 2020 2:42 pm Shortly you will be able to specify which channels you want to record from (ATSC 1.0 vs 3.0), or let it pick automatically.
Nick
Is this going to happen at the device level or only implemented in the HDHomeRun app?
It involves both firmware and app awareness.

Nick

CBme
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Re: AC-4 Audio?

Post by CBme »

I don't seen anything in that statement about Plex needing an update to work with the ATSC 1.0 channel in this workaround. It is certainly possible but Plex currently lists the channels HDHR device shows it. It will display whatever the HDHR lists. So, without a statement to the contrary, my expectation is that if the HDHR lists all the ATSC 1.0 in channels in their normal Virtual channel locations and lists the 3.0 as 100+ channels, that is what Plex should show.
Last edited by CBme on Sun Dec 27, 2020 11:37 pm, edited 1 time in total.

NedS
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Re: AC-4 Audio?

Post by NedS »

The "100+" workaround will allow ATSC 1.0 channels to be used in Plex without Plex getting an update.

Long term, we would like to make it possible for both our app and third party apps to easily select the correct channel for the needs of that software/hardware, but how to best handle that is still being worked out, and likely will require an update for the third party software to take full advantage of.

EDIT to clarify: Plex will still show the ATSC 3.0 channels as being 100+, but I don't think they'll be used for recordings, as the Plex software is not expecting those channel numbers. They can still be selected for live TV, but still won't have audio at the moment.

vanhln
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Re: AC-4 Audio?

Post by vanhln »

CBme wrote: Sun Dec 27, 2020 10:54 pm
darcilicious wrote: Sun Dec 27, 2020 7:57 pm
rainlake wrote: Sun Dec 27, 2020 7:38 pm
Nickk said they will move ATSC 3 to 100+ so plex should work without problem.
That'd be nice -- assuming what he originally said no longer applies :)
Plex should work without issue with the workaround specified as it is simply additional channels, not some new way to select a channel and then select 1.0 or 3.0 that Plex wouldn't understand.
Plex likely won't be able to automatically map the atsc 3.0 100+ channels correctly but we should be able to do so manually as you can now (though you might need to drop the atsc 1.0 if you want to do that as you don't seem to be able to map two channels to the same guide channel). Of course it still won't play AC4 until FFMpeg gets updated.

viewtopic.php?f=133&t=74778
Tuning ATSC 1.0 vs 3.0 channels:
We have an ongoing effort to support multiple channels with the same virtual channel number to support user selection between ATSC 1.0 and ATSC 3.0. We want to get everyone up and running now so the pending firmware release has a short term workaround moving the ATSC 3.0 channels to 100+ channel numbers.

I'm doing more OTA recordings on Plex since I cut the cord COMPLETELY, so I need more tuners... HDHomerun Connect 4K is on order. ATSC 3.0 doesn't seem close in NE Ohio, so hopefully kinks will be worked out by then...

talkenrain
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Re: AC-4 Audio?

Post by talkenrain »

Nvidia Shield Pro App update: 20201226

Now crashes on more that 50% of available ATSC 3.0 channels (seconds after tuning in). Prior release would crash on only 1 channel. Don't see or hear any difference. Left channel still dominates.

nickk
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Re: AC-4 Audio?

Post by nickk »

talkenrain wrote: Mon Dec 28, 2020 11:31 am Nvidia Shield Pro App update: 20201226
Now crashes on more that 50% of available ATSC 3.0 channels (seconds after tuning in). Prior release would crash on only 1 channel. Don't see or hear any difference. Left channel still dominates.
Simple thing first is to check your reception. We have confirmed an issue where the app can crash if there is a chunk of audio missing. A fix is in the works now.

Nick

peanutbutter71
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Re: AC-4 Audio?

Post by peanutbutter71 »

I compiled this fork of ffmpeg on linux:

https://github.com/richardpl/FFmpeg/tree/ac4

and used the ffplay with it to play some sample ac4 files and atsc 3 recordings (https://onedrive.live.com/?authkey=%21A ... 31209CB69D) with ac4 audio and it works. Only one file out of like 5 it wouldn't play so this is promising.

I don't think this is in the main trunk for ffmpeg, but this is at least promising.

tmm1
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Re: AC-4 Audio?

Post by tmm1 »

Were there error messages on the file which did not play? Which station was it from?

peanutbutter71
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Re: AC-4 Audio?

Post by peanutbutter71 »

tmm1 wrote: Mon Dec 28, 2020 4:06 pm Were there error messages on the file which did not play? Which station was it from?
Actually I think all the video recordings played, it was this Lil Wayne audio recording that wouldn't play.

./ffplay ~/Desktop/01\ -\ Believer\ \(feat.\ Lil\ Wayne\).mp4
ffplay version 4.3.git Copyright (c) 2003-2020 the FFmpeg developers
built with gcc 9 (Ubuntu 9.3.0-17ubuntu1~20.04)
configuration:
libavutil 56. 62.100 / 56. 62.100
libavcodec 58.115.102 / 58.115.102
libavformat 58. 65.100 / 58. 65.100
libavdevice 58. 11.103 / 58. 11.103
libavfilter 7. 94.100 / 7. 94.100
libswscale 5. 8.100 / 5. 8.100
libswresample 3. 8.100 / 3. 8.100
[ac4 @ 0x7f698c0038c0] substream audio data overread: 1153B f=0/0
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/home/john/Desktop/01 - Believer (feat. Lil Wayne).mp4':
Metadata:
major_brand : mp42
minor_version : 1
compatible_brands: mp42isom
creation_time : 2019-12-08T11:50:13.000000Z
Duration: 00:03:25.01, start: 0.000000, bitrate: 257 kb/s
Stream #0:0(und): Audio: ac4 (ac-4 / 0x342D6361), 48000 Hz, 7.1, fltp, 256 kb/s (default)
Metadata:
creation_time : 2019-12-08T11:50:13.000000Z
handler_name : sound handler
vendor_id : [0][0][0][0]
[ac4 @ 0x7f698c44ae80] substream audio data overread: 1153
[ac4 @ 0x7f698c44ae80] substream audio data overread: 598
[ac4 @ 0x7f698c44ae80] substream audio data underread: 8
Segmentation fault (core dumped)

peanutbutter71
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Re: AC-4 Audio?

Post by peanutbutter71 »

There's a clip of a soccer match where it is playing the audio, but I guess the track with the announcer's audio is really muffled. Who knows if it was broadcast that way or it's a problem with ffmpeg. At least there is code for AC-4 decoder, I thought we'd have to wait a lot longer.

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