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giaur · 2021-01-04, 00:03

(2021-01-04, 00:00)emveepee Wrote: I can play the sample and while it is shorter than expected and a single program on the mux would have been easier, I can only toggle through audio tracks 2, 3 and 4 I assume because track 5 reports 0 channels.

Martin

I have no access to any dvb-t2 mux currently, once I get access I can try to make dump or record with Tvheadend

emveepee · 2021-01-04, 00:09

The point of my question was to find out if this AC4 stream is actually valid, ie can you hear a fourth audio channel anywhere else?

Martin

giaur · (This post was last modified: 2021-01-04, 01:24 by giaur.)

Other audio streams are valid, so ac4 should be valid too. Are you able to play it with your patched ffmpeg? I actually can't hear anywhere, because I don't know any software that supports ac4. But on tv it works (live, I can't check the file)

emveepee · 2021-01-04, 01:47

No as I showed earlier the patched ffmpeg shows 0 channels. That is different from the standard bin data. If you have four audio channels on your TV then you should submit your sample on the ffmpeg patch thread. It might help to identify the TV model that supports AC4 from DVB-T2

Martin

ferrellsl · 2021-01-19, 08:31

(2021-01-04, 01:47)emveepee Wrote: No as I showed earlier the patched ffmpeg shows 0 channels. That is different from the standard bin data. If you have four audio channels on your TV then you should submit your sample on the ffmpeg patch thread. It might help to identify the TV model that supports AC4 from DVB-T2

Martin

I've compiled a version of ffmpeg that supports ATSC3.0/AC-4 streams and it works great on said streams in the Phoenix area. I used MSYS2 as my build environment as I wanted Windows x86_64 binaries. You can download the binaries from my DropBox account here: https://www.dropbox.com/s/eene7ecard5xki...4.zip?dl=1

If you experience video stuttering and VQ dropping to 0 after a few minutes of streaming, add the infinite buffer and video sync switches to your script or command line. I.e.: ffplay.exe -i "http://192.168.2.142:5004/auto/v161.1?transcode=native" -infbuf -sync video

I've been using this build to test ATSC3.0/AC-4 streams on my HDHomeRun 4K tuner. I hope others here might find the binaries useful.

ferrellsl · 2021-01-19, 21:40

(2021-01-19, 08:31)ferrellsl Wrote:
(2021-01-04, 01:47)emveepee Wrote: No as I showed earlier the patched ffmpeg shows 0 channels. That is different from the standard bin data. If you have four audio channels on your TV then you should submit your sample on the ffmpeg patch thread. It might help to identify the TV model that supports AC4 from DVB-T2

Martin

I've compiled a version of ffmpeg that supports ATSC3.0/AC-4 streams and it works great on said streams in the Phoenix area. I used MSYS2 as my build environment as I wanted Windows x86_64 binaries. You can download the binaries from my DropBox account here: https://www.dropbox.com/s/eene7ecard5xki...4.zip?dl=1

If you experience video stuttering and VQ dropping to 0 after a few minutes of streaming, add the infinite buffer and video sync switches to your script or command line. I.e.: ffplay.exe -i "http://192.168.2.142:5004/auto/v161.1?transcode=native" -infbuf -sync video

I've been using this build to test ATSC3.0/AC-4 streams on my HDHomeRun 4K tuner. I hope others here might find the binaries useful.

I forgot to mention for those who want to conduct their own build, the source tree can be found here: https://github.com/richardpl/FFmpeg/tree/ac4

giaur · 2021-01-19, 21:51

Ok maybe I will try to build on Linux

ferrellsl · 2021-10-14, 07:30

(2021-01-19, 21:51)giaur Wrote: Ok maybe I will try to build on Linux

I've completed a successful build of Kodi that supports ATSC3/HEVC/AC-4 audio. It is a 64-bit Windows build and has been tested on Windows 10 & 11 with the latest version of NextPVR. It successfully plays all the ATSC3 broadcasts in the Phoenix area but it hasn't been tested in any other locations. If anyone wants to download and test this build, contact me for a download link. The user assumes the responsibility for installing and configuring NextPVR correctly as well as configuring the NextPVR add-on within Kodi. I created this build because I'm cheap and didn't want to pay the folks over at SiliconDust just for the privilege of being able to schedule, record, and play back the new ATSC3 stations in my area. This build targets users of the new SiliconDust HDHomeRun tuners that support the ATSC3 standard so folks who don't own ATSC3 compatible tuners can just ignore this build.

RKCRLR · (This post was last modified: 2021-10-21, 02:38 by RKCRLR.)

I'm pretty ignorant on how this stuff all ties together but have a question. I've asked this question other places but haven't received an answer.
I have a 2019 Shield TV Pro that uses the MS12 Dolby Stack which decodes AC-4. I'm currently running Kodi Matrix 19.2 on the Shield TV and use it to view OTA recordings using the TVHeadend client. I have a Ugoos X3 box that I use as my TVHeadend server and a SiliconDust ATSC 1.0 tuner. I have the Shield TV connected to my Atmos capable receiver via HDMI and can play Atmos soundtracks.

If I purchase a SiliconDust ATSC 3.0 tuner, can I somehow tell Kodi to use the Shield TV Pro AC-4 decoder and send the output to my receiver?

giaur · 2021-11-13, 10:19

Any news on this?

BeefJerky · (This post was last modified: 2021-12-22, 06:57 by BeefJerky.)

Bumping this. I don't care if Kodi can decode the AC-4 itself, as my Shield TV and Fire Stick 4Ks can handle that themselves. There needs to be a way to let this pass through to the existing hardware decoders.

EDIT: I forgot I do have one Shield TV 2017, so I guess I would like AC-4 decode. But, even passthrough to the existing decoder is much better than what we have now.

BeefJerky · 2022-04-19, 10:34

Bumping this. Even without FFmpeg support, is there really no way we can get a passthrough option, either to the built-in decoder on the streaming device (i.e. Shield TV Pro), or to a supported receiver. Apparently receivers with Atmos support can decode AC-4 if Kodi were willing to bitstream it.

RKCRLR · 2022-04-19, 17:31

(2022-04-19, 10:34)BeefJerky Wrote: Bumping this. Even without FFmpeg support, is there really no way we can get a passthrough option, either to the built-in decoder on the streaming device (i.e. Shield TV Pro), or to a supported receiver. Apparently receivers with Atmos support can decode AC-4 if Kodi were willing to bitstream it.

I bumped my thread on the Nvidia forum. Nvidia support responded that the version of the MS12 stack used on SHIELD does not contain AC-4 support.

BeefJerky · (This post was last modified: 2022-04-19, 20:46 by BeefJerky.)

(2022-04-19, 17:31)RKCRLR Wrote:
(2022-04-19, 10:34)BeefJerky Wrote: Bumping this. Even without FFmpeg support, is there really no way we can get a passthrough option, either to the built-in decoder on the streaming device (i.e. Shield TV Pro), or to a supported receiver. Apparently receivers with Atmos support can decode AC-4 if Kodi were willing to bitstream it.

I bumped my thread on the Nvidia forum. Nvidia support responded that the version of the MS12 stack used on SHIELD does not contain AC-4 support.

That's certainly an interesting response on their part. If I'm not mistaken, the native HDHomeRun app uses the 2019 Shield Pro's AC-4 decoder rather than the cloud service.

EDIT: It looks like you're right. I just tried the native HDHomeRun app on my Shield TV Pro 2019, and it just output stereo from an ATSC3 channel, so it must be using the cloud service. Too bad.

Now, I wonder if it's really true that Atmos receivers can decode AC-4 audio. If true, bitstream support for AC-4 in Kodi would solve the issue. If not, then we're really stuck until FFmpeg gets around to adding AC-4 support, which could take years based on what I'm seeing.

RKCRLR · 2022-04-19, 21:57

(2022-04-19, 20:40)BeefJerky Wrote:
(2022-04-19, 17:31)RKCRLR Wrote:
(2022-04-19, 10:34)BeefJerky Wrote: Bumping this. Even without FFmpeg support, is there really no way we can get a passthrough option, either to the built-in decoder on the streaming device (i.e. Shield TV Pro), or to a supported receiver. Apparently receivers with Atmos support can decode AC-4 if Kodi were willing to bitstream it.

I bumped my thread on the Nvidia forum. Nvidia support responded that the version of the MS12 stack used on SHIELD does not contain AC-4 support.

Now, I wonder if it's really true that Atmos receivers can decode AC-4 audio. If true, bitstream support for AC-4 in Kodi would solve the issue. If not, then we're really stuck until FFmpeg gets around to adding AC-4 support, which could take years based on what I'm seeing.

I suspect that Atmos receivers would licensed to provide AC-4 support but it is up to the manufacturers to incorporate it. And then the question becomes can it be done by a firmware update or is different hardware required.