Kodi AC-4 (GitHub) for Windows (for ATSC 3.0 TV)

[DSperber]

If it isn't already known, I have been given clearance by the GitHub project developer to share the availabllity of his own personally modified version of Kodi for Windows. It contains built-in native support for OTA broadcast ATSC 3.0 channels now rolling out across the country, and its new AC-4 audio along with HEVC video.

I have bought a Silicon Dust HDHomeRun Flex-4K network tuner box to specifically get me going in the new "NextGen" ATSC 3.0 world. This new standard will support video of not only 720p and 1080i supported by MPEG-2, but also 1080p and potentially 2160p supported by HEVC. And audio is improved as well over the AC-3 5.1 supported by ATSC 1.0, with AC-4 audio potentially also supporting 7.1 and even 7.1.4 Dolby Atmos.

While HEVC is freely available from the MS Store for Win10/11, the LAV Filters work for HEVC in Win7.

However support for AC-4 is essentially totally absent in widely available software today. Dolby has licensed the AC-4 codec to TV manufacturers for use in their built-in tuners supporting both ATSC 1.0 and ATSC 3.0, typically for TV models 2021 and newer. Certainly Sony, LG, etc., have taken this path. So if you buy a new TV you can automatically get support of OTA ATSC 3.0 channels (assuming you use a roof antenna or rabbit ears, of course, to receive them).

As of right now no AVRs have yet been produced by any manufacturer that support decoding AC-4, so bitstreaming (pass-through) the AC-4 audio to an external sound system is not an option. Also no currently available streaming devices provide support for decoding AC-4, so their pass-through audio option is similarly worthless for client apps like NextPVR running on them.

Even for apps written to run on new TV's (like the official HDHR client app for LG OLED) can only go as far as making use of the built-in AC-4 support (e.g. LG has had built-in support for AC-4 on all OLED TV models since 2017), which is designed to produce decoding support needed only for the two speakers in the TV. So its output (say via ARC/eARC bitstreamed to an external audio system via HDMI) is only 2-channel L/R 2.0 even if the original audio was AC-4 5.1.

In other words... at the moment we are still at the bleeding edge of ATSC 3.0. Appropriate hardware to actually make use of the new AC-4 audio is unavailable. Plus, there are really very few ATSC 3.0 channels available yet in the 36 cities where initial rollout has started. So far, only FOX has really been the major leader in the early charge to upgrade their local affiliates with ATSC 3.0 channels along with the existing ATSC 1.0 versions of the same channel. All the other channels will follow over the next year or two or three, but for now it's essentially only FOX which has taken the lead on ATSC 3.0.

So whereas FOX stations nationwide have all used 720p as their video protocol for ATSC 1.0, the new ATSC 3.0 versions of FOX channels are broadcasting in native 1080p. Looks beautiful upscaled to 2160p for display on a 4K LG OLED TV! Also, other early rollout channels that were interlaced 1080i on ATSC 1.0 are now also delivering native 1080p for the same program on ATSC 3.0.

We're probably years away from this really being the widespread norm, and people replacing their old equipment only capable of handling AC-3 and ATSC 1.0 broadcast TV with new equipment properly supporting ATSC 3.0 for both HEVC video and AC-4 audio.

Which brings me to the point of this post: there is available today a GitHub project which is "Kodi AC-4" for Windows 7, 10 and 11. And it delivers decoded AC-4 audio... natively, using a beta version of FFMPEG that adds support for AC-4.

So because it is actually Kodi it utilizes the NextPVR backend for its live TV and recording services, which in turn supports my Flex-4K tuners.  And it uses the beta FFMPEG to support AC-4 natively, so ATSC 3.0 channels containing AC-4 audio are perfectly supported and deliver 5.1. You will get 5.1 audio out, either on your PC or pass-through bitrstreamed to an external audio system. And if you connect your Windows Kodi-enabled desktop PC graphics card or laptop HDMI output to an external audio system, you can get true 5.1 audio while enjoying the native 1080p video upscaled to 2160p, on your home entertainment system. NATIVE AC-4 SUPPORT IN KODI!

Here is the GitHub project page, with all the details. It also shows my recent conversation with the author. So everything I've learned about and questioned over the past few days is documented there in the comments below. All his answers are in the comments below. You will know everything I know, because it's all written down there.

I have now installed Kodi AC-4 on both my Win7 and Win10 systems. Note that it uses PVR.NEXPVR as its add-on, which is the one from Graeme Blackley. Turns out we had some problems getting the add-on installed initially, because the Kodi distribution had been changed since November when this project was posted on GitHub. The solution/workaround is to download the add-on manually in ZIP form, and then place the un-zipped folder in Kodi's \addons folder. Then the add-on can be configured and enabled as normal (being sure to un-check the "automatically apply updates" option). 

And it works perfectly, albeit it only for Windows. But if you're looking for the perfect solution to how to properly support the new Flex-4K product from SD, and the new ATSC 3.0 channels with built-in native support for the imbedded AC-4 audio, THIS IS THE CLIENT FOR YOU as your Windows client!

[ferrels]

Hi. Thanks for the kind words DSperber. For folks who want to test this AC-4 friendly version of Kodi, here's the download link: https://www.dropbox.com/s/sz1wq5kriq2l2v...p.exe?dl=0
To work properly with NextPVR as your back-end, you will need to add Graeme Blackley's NextPVR add-on to Kodi, ver. 20.1.3.

This is a Kodi Nexus (20.0 Alpha build). The Kodi Add-ons repositories seem to be in a state of flux with Nexus at the moment so when attempting to add PVR Clients, you won't see any PVR Clients available if you browse the repository. To get around this, install Graeme's add-on as a ZIP file. You can get the ZIP file here: https://www.dropbox.com/s/sz1wq5kriq2l2v...p.exe?dl=0

Just refer to the link that DSperber shared for detailed installation instructions if you need them: https://github.com/ferrellsl/VideoPlayer...5d2cb25dd1

[sub]

To work properly with NextPVR as your back-end, you will need to add Graeme Blackley's NextPVR add-on to Kodi, ver. 20.1.3.

That is me. Martin has pretty much been the sole maintainer of it the last few years though.

[ferrels]

To work properly with NextPVR as your back-end, you will need to add Graeme Blackley's NextPVR add-on to Kodi, ver. 20.1.3.

That is me. Martin has pretty much been the sole maintainer of it the last few years though.

Hi.  I'm really new to Kodi so I have no idea who the personalities are behind the add-ons and such or who the moderators/admins are.  I didn't start using Kodi until just a few months ago when I was searching for a TV client that might support ATSC3.0/AC-4 or be easily modified to that end.  Kodi was a very good candidate for modification so I decided to take a stab at building it and linking it against a modified version of ffmpeg that supports AC-4 audio.  I was grateful for the detailed build instructions without which I would have surely failed.  I think it was early Nov. when I completed the build and posted about it here but no one seemed interested.  I may have simply posted in the wrong area because I'm really new to the forum here as well and not familiar with the layout.

Anyway, I hope folks here find this version of Kodi as useful as I have.  For folks who want the sources to this modified version of ffmpeg that supports AC-4 audio, here's a download link:  https://www.dropbox.com/s/2ja2olyyqtk73t...d.zip?dl=0

The binaries within the archive were built using Visual Studio.  DLLs, EXEs, .def and .lib files are included to make life easier for folks who don't want to go thru the build process for ffmpeg.

The Kodi sources that I used for my build were directly off github back in Nov.

[sub]

FYI, there is later branch of ffmpeg with ac4 support at https://github.com/sub3/FFmpeg/tree/ac4

Still based on Paul Mahol's changes, but a few further minor tweaks. My specific interest was around the raw ATSC 3.0 DASH content, rather than the remuxed HDHR output.

[ferrels]

FYI, there is later branch of ffmpeg with ac4 support at https://github.com/sub3/FFmpeg/tree/ac4

Still based on Paul Mahol's changes, but a few further minor tweaks. My specific interest was around the raw ATSC 3.0 DASH content, rather than the remuxed HDHR output.

Yes, that later branch has problems so I stuck with the earlier branch.

[sub]

Yes, that later branch has problems so I stuck with the earlier branch.

What problems exactly? I literally posted it like 5 minutes go, so you definitely have not used this version yet.

[ferrels]

Yes, that later branch has problems so I stuck with the earlier branch.

What problems exactly? I literally posted it like 5 minutes go, so you definitely have not used this version yet.

Why the accusatory tone? Yes, I have used the later branch and it refused to decode the HEVC streams coming from my SiliconDust ATSC3.0 tuner. No one is saying you even have to use the earlier branch. Use whatever you like.

[sub]

Yes, that later branch has problems so I stuck with the earlier branch.

What problems exactly? I literally posted it like 5 minutes go, so you definitely have not used this version yet.

Why the accusatory tone? Yes, I have used the later branch and it refused to decode the HEVC streams coming from my SiliconDust ATSC3.0 tuner.

It's not related to any other branch you may be thinking of.

It is the first time this branch has been available. It's based on the current ffmpeg. ffplay is playing HEVC from SiliconDust recordings.

[ferrels]

Yes, that later branch has problems so I stuck with the earlier branch.

What problems exactly? I literally posted it like 5 minutes go, so you definitely have not used this version yet.

Why the accusatory tone? Yes, I have used the later branch and it refused to decode the HEVC streams coming from my SiliconDust ATSC3.0 tuner.

It's not related to any other branch you may be thinking of.

It is the first time this branch has been available. It's based on the current ffmpeg. ffplay is playing HEVC from SiliconDust recordings.

Well, that's fine.  I was just providing folks with the version of ffmpeg that I used to create an AC-4 friendly version of Kodi.  Take it or leave it.  Doesn't really matter to me as I have a version of Kodi now that works perfectly for me based off of the ffmpeg sources that I provided in the zip archive.  You're free to use to use whatever you want.