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oldtvwatcher · (This post was last modified: 2021-05-05, 02:00 by oldtvwatcher.)

I am just wondering if any LINUX users in the land of ATSC 3.0 where you actually have stations on the air have been able to record programs in ATSC 3.0 using Tvheadend and then successfully play them using Kodi (with the Tvheadend PVR plugin). ATSC 3.0 has recently arrived in my area but those HDHomeRun devices are pretty pricey at $200 a pop, and although they have four tuners, only two of them will receive ATSC 3.0. But maybe it would be worth it IF they work okay with Tvheadend and Kodi, but I have been reading comments about it either not working at all, or that the video freezes and there is no sound (because they use AC-4 audio and apparently ffmpeg can't handle that yet?). But those comments were from about four months ago. So what I am asking is, are there any ATSC 3.0 viewers here that have recent experience using this combination (without having to futz around with it), and if so does it work well for you or not?

Also, just to be clear, if you were able to get it to work but only after jumping through all kinds of hoops that included compiling software from scratch, then the answer is no, and for me you could just leave it at that. I'm not a programmer or a developer or a Linux expert. I just run Kodi in Ubuntu Linux because in the past it has worked pretty well (other than the problems getting the remote to work after they came out with that godawful new version of lirc, until I found the article that shows how to revert to the old version), so anything that involves that extra level of expertise is beyond me. The last thing I need is any more problems, and my fear is that if I try to move to ATSC 3.0 too early that's exactly what I am going to get.

emveepee · 2021-05-05, 05:08

(2021-05-05, 01:57)oldtvwatcher Wrote: Also, just to be clear, if you were able to get it to work but only after jumping through all kinds of hoops that included compiling software from scratch, then the answer is no, and for me you could just leave it at that.

No.

Martin

oldtvwatcher · 2021-05-05, 05:35

(2021-05-05, 05:08)emveepee Wrote:
(2021-05-05, 01:57)oldtvwatcher Wrote: Also, just to be clear, if you were able to get it to work but only after jumping through all kinds of hoops that included compiling software from scratch, then the answer is no, and for me you could just leave it at that.

No.

Martin

Thanks, no point in wasting any money then until they get it worked out. Much appreciated!

ferrellsl · 2021-10-14, 07:39

(2021-05-05, 05:35)oldtvwatcher Wrote:
(2021-05-05, 05:08)emveepee Wrote:
(2021-05-05, 01:57)oldtvwatcher Wrote: Also, just to be clear, if you were able to get it to work but only after jumping through all kinds of hoops that included compiling software from scratch, then the answer is no, and for me you could just leave it at that.

No.

Martin
Thanks, no point in wasting any money then until they get it worked out. Much appreciated!

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.

smicklem · 2021-10-23, 08:41

(2021-10-14, 07:39)ferrellsl Wrote: 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.

I started to get excited until I saw this was for Windows. Like you, I'm cheap, but that also includes not wanting to pay Microsoft for a copy of Windows when Ubuntu Linux is free, and more secure in my opinion. Also, I use Tvheadend as my PVR backend.

But even so, I hope that the Kodi developers will take some interest in what you have done because it sounds like ATSC3 is coming whether any of us really want it or not, and as far as I know Kodi currently has no support for it, with the AC-4 audio being the main issue from everything I've read.

noggin · (This post was last modified: 2021-10-23, 11:20 by noggin.)

Looks like ffmpeg support for AC-4 audio is getting somewhere https://trac.ffmpeg.org/ticket/8349

AIUI that will be the key factor in supporting playback of ATSC 3.0-delivered content in Kodi cross-platform. Once the version of ffmpeg used in Kodi supports AC-4 decoding, then that will make things potentially much easier.

The PVR backend used will need to support the ATSC 3.0 tuner (like the new HDHR) and the multicast IP-over-RF system that ATSC 3.0 uses to deliver DASH/ROUTE, or similar, streams. Some tuners like the HDHR developer edition will re-wrap the DASH/ROUTE (?) stuff into an old-skool MPEG2 transport stream (optionally) I believe - so that makes the transition easier (note - this leaves the video in HEVC/h.265 and audio in AC-4 - it just changes the way it is carried - it's not transcoding to MPEG2 video and AC-3 audio)

smicklem · 2021-10-23, 18:12

My experience with free-to-air satellite signals is that Tvheadend just records whatever transport stream it receives from the tuner, with minimal processing. So if the video is HEVC/h.265 and the audio is AC-4, that is exactly how Tvheadend will save it. It is then up to whatever player you use to decode it. I don't think the HEVC/h.265 will be a huge issue except on underpowered systems, for example I doubt that a Raspberry Pi will be able to deal with that. Also many GPUs won't decode those so in such cases the decoding has to be delegated to the CPU, which may or may not be a problem.

ffmpeg does many things well but there are some things it doesn't do well, or at all. Its support of USA/Canada style closed captioning is terrible - VLC displays closed captions just fine, but on some channels Kodi either doesn't display them at all, displayed a very garbled version, or displays them all in the same font with no distinction between text and music, and that's because ffmpeg's support of US-style closed captions is minimal at best. As for AC-4, the ffmpeg developers seem to act as if they couldn't care less if it ever gets added - all the action on AC-4 is coming from third parties that are making custom builds. Sometimes I wish Kodi would use whatever decoding engine VLC uses, although there could be drawbacks to doing that which I am not aware of.

emveepee · 2021-10-23, 18:27

There is nothing intrinsically "Windows" about the ffpeg patch for AC-4. I've applied it to Kodi and to ExoPlayer and it appears to decode audio ok. Also playing ATSC 3.0 with the cheapest ($20-30) ONN and TiVO 4k devices HEVC/AC-4 is not an issue. Not sure why it has to run on the RPi to considered relevant.

It seems like you are confusing the closed captioning decoding and rendering engine with ffmpeg which there is no doubt that it can be improved in Kodi.

Also note AFAIK nothing in the non-commercial realm decodes AC-4 xml subtitles

Martin

smicklem · 2021-10-23, 23:19

(2021-10-23, 18:27)emveepee Wrote: There is nothing intrinsically "Windows" about the ffpeg patch for AC-4. I've applied it to Kodi and to ExoPlayer and it appears to decode audio ok. Also playing ATSC 3.0 with the cheapest ($20-30) ONN and TiVO 4k devices HEVC/AC-4 is not an issue.

Will either of those act as a tuner for any of the PVR programs that Kodi supports? Specifically a PVR program that runs under Linux?

(2021-10-23, 18:27)emveepee Wrote: Not sure why it has to run on the RPi to considered relevant.

Never said it did, I was just making a point about underpowered hardware possibly having problems playing that type of video.

(2021-10-23, 18:27)emveepee Wrote: It seems like you are confusing the closed captioning decoding and rendering engine with ffmpeg which there is no doubt that it can be improved in Kodi.

Also note AFAIK nothing in the non-commercial realm decodes AC-4 xml subtitles

All I know is there are some recordings where VLC has no problem playing the subtitles but Kodi can't seem to decode them, or in some cases doesn't seem to even know they are there. So I guess that would be decoding. Then there is the fact that even when it does decode the subtitles it puts everything in the same font, with no italics and no musical note characters to indicate where it's song lyrics and not speech, and I suppose that would be rendering? As for not being able to get subtitles from AC-4, that does not surprise me.

emveepee · 2021-10-24, 01:08

The NextPVR backend runs on most platform Linux, Docker, current CE/LE (using a package install) and MACOS not just Windows. There is no Kodi support for AC-4, since Team Kodi doesn't want to support it but you can build your own ffmpeg on linux from the PR. On any platform of course you can schedule and manage the recordings, you just won't have sound on the AC-4

So for now, if you don't want the HDHR app you are stuck with the Android NextPVR client which BTW via ExoPlayer has pretty good closed captioning however again no ATSC 3.0 captioning. I also haven't tested comskip on ATSC 3.0 since I don't live in the US but if the EDL file is good it will work.

Martin

smicklem · 2021-10-24, 10:18

(2021-10-24, 01:08)emveepee Wrote: The NextPVR backend runs on most platform Linux, Docker, current CE/LE (using a package install) and MACOS not just Windows. There is no Kodi support for AC-4, since Team Kodi doesn't want to support it but you can build your own ffmpeg on linux from the PR. On any platform of course you can schedule and manage the recordings, you just won't have sound on the AC-4

So for now, if you don't want the HDHR app you are stuck with the Android NextPVR client which BTW via ExoPlayer has pretty good closed captioning however again no ATSC 3.0 captioning. I also haven't tested comskip on ATSC 3.0 since I don't live in the US but if the EDL file is good it will work.

Martin

noggin · 2021-10-24, 17:06

(2021-10-23, 18:12)smicklem Wrote: My experience with free-to-air satellite signals is that Tvheadend just records whatever transport stream it receives from the tuner, with minimal processing.

Yes - though in this case there isn't a transport stream with ATSC 3.0 - it uses DASH/ROUTE (?) instead - so there may be additional support required (though you may well be able to do this using an ffmpeg script as an IPTV source in TV Headend) if ffmpeg can rewrap.

emveepee · 2021-10-24, 22:40

The Silicon Dust ATSC 3.0 device is actually converting the ATSC 3.0 into an mpeg-ts http stream just like they do with ATSC 1.0, Cable Card and DVB.

Martin

smicklem · 2021-10-24, 23:35

(2021-10-24, 22:40)emveepee Wrote: The Silicon Dust ATSC 3.0 device is actually converting the ATSC 3.0 into an mpeg-ts http stream just like they do with ATSC 1.0, Cable Card and DVB.

Martin

It's good that they do that, and that makes it all the more surprising that they don't also convert the audio into a more widely accepted format, such as AC-3.

emveepee · (This post was last modified: 2021-10-25, 00:27 by emveepee.)

Transcoding firmware and licensing would cost more and you lose the future benefits of AC-4. No doubt some DVB users would benefit from AAC 5:1 transcoding to AC-3 too. 10-15 years ago users didn't want AC-3 and wanted 2:0 MPEG2 audio. Times change.

That discussion is better for the SiliconDust forum anyway. Maybe if other vendors enter the market you will get more choice.

Martin