Server Version#: PlexMediaServer-1.20.3.3483-211702a9f-x86_64
Player Version#: Firefox on Fedora Linux
Tuner Make/Model: HDHomeRun Connect 4K
Guide/Lineup name:
Using XMLTV?: no
Channel number/Name: Phoenix 15.1 KNXV-NG
Plex records and live plays the ATSC3.0 channel but there is no sound. Silicondust tells me that’s because Plex doesn’t (yet) support AC-4 sound. So let me spend my 2 cents and encourage timely development of that feature! Any chance I can keep my hopes up?
Plex doesn’t yet have it because FFMPEG have it.
FFMPEG had, and closed, one request. It reopened the request 12 months ago.
You can search and see no progress has been made in that regard.
I’m told this hangs on FFmpeg ticket #8349
I’ve sent off a message to Engineering.
I will report back when I know more.
Thanks for the update. I’d really like to have sound for these channels again. Why did they pick AC-4 for the audio codec?
Since I started this thread my PLEX server has been upgraded to PlexMediaServer-1.20.4.3517-ab5e1197c-x86_64 and the HDHomeRun Connect 4K tuner has had several firmware updates. The result is that the sever now categorically refuses to record any ATSC3.0 streams claiming that there isn’t a valid signal (not even the picture it showed earlier). Now, I know that’s not the case since HDHomeRun’s own app on client platforms that have the needed HEVC and AC4 support (for me that’s my Windows 10 PC and a LG TV) the channels work flawlessly - both picture and sound.
I realize that this is leading edge and I can’t expect everything to work right immediately - that’s going to take time. However, I believe we need to recognize that this is the future and it’ll be mainstream soon enough that it behooves us to get ready. So my question is: what is PLEX’s plan and timeline to get ATSC3.0 broadcast supported?
Yes, this is the “not very distant future” as many products and TV stations have embraced ATSC 3.0. In my market (Portland, Or), all the local channels are now broadcasting using ATSC 3.0. There is a growing number of TV manufactures including ATSC 3.0 tuners as well so I don’t think it will be long before this will become a real issue for users of PLEX live TV and DVR.
I’ve spoken to engineering staff of some of the local broadcasters, they have told me there are really great reasons to move to ATSC 3.0 beyond the possibility of 4k including improved multi-path rejection, more available channels, much improved audio, etc…
Please make this a priority to address before it becomes a “black eye” for this otherwise great platform. Or at least give an update and/or reasons why it’s going to take some time (IE, licensing, technology challenges, roadblocks, etc)…
I know that some HDHomeRun devices can transcode the video (to H.264?) before passing it to Plex.
I don’t know if that feature exists in the ATSC 3.0 devices. Or if it transcodes audio, too. If it does, could it be a potential way to sidestep the AC-4 issue?
(Of COURSE AC-4 is a Dolby thing. Of course…)
(Edit, much later: I don’t think any modern HDHomeRun devices can transcode on the fly. Darn.)
Add Tampa FL to the 4k Local channels no audio problem. They just turned on the service yesterday.
If I read https://gstreamer.freedesktop.org/releases/1.18/ correctly, GStreamer has AC4 support. Can that be leveraged?
Seattle is now live and Plex Live TV/DVR isn’t usable due to this AC4 problem and that it doesn’t support HVEC interlaced content so the image gets squashed as it reads 1080i as 1920x540p (CBS is broadcasting this way here unfortunately). EDIT: Squished 1080i video was resolved by the station “forcing the aspect ratio” in their broadcast.
Everyone who wants this in the near future or is already blocked by the issue should sign up at FFMpeg and upvote the issue and apply comments as appropriate.
AC4
HVEC Interlaced problem
According to https://trac.ffmpeg.org/ticket/8349#comment:29 the AC4 ffmpeg patches at https://github.com/richardpl/FFmpeg/tree/ac4 work. If a test version of PLEX with those patches could be created I would be thrilled to try it out…
@ChuckPa is this information above about the patch possible to make work?
Jason,
I’m not sure where Engineering is at with the ATSC 3.0 effort.
I’m also not the right person to ask about FFMPEG.
I did get the ATSC 3.0 EPG problem submitted to them last weel.
You all do realize there is one big gating factor in this work?
Whichever team member gets assigned (the transcoder team), that person needs to have ATSC 3.0 source material from their provider to work with. ( You know they don’t just compile something and throw it to the users to try like I do 
)
I will ask on Monday but I wouldn’t hold my breath too much.
cough cough
Plex not withstanding …
there’s nothing stopping you from spinning your own ffmpeg from the public source and trying it yourself.
It won’t be integrated into PMS but will allow you to take ATSC 3.0 captured material and play it as if a “normal tv series” as proof of concept and personal satisfaction.
I’m sure a few of us could hook you all up with transport streams, if desired. Just reach out!
Obviously not the same as having it live via antenna, but it would be a good starting point for testing.
Thanks for the reply. I do appreciate it. I have it working on my Galaxy S s20 5G through emby but the screen is too small, it’s not practical, and want to have everything in one system lol. But I do like my local channels in full 1080 at 60 frames per second!! Thought I was getting it because of 4K but that was kind of misleading:(.
I use the Nvidia Shield player. It plays 2160p 59.94 fps without blinking. It even does its own transcoding down to 1080p for the TV with HDR -> SDR tone mapping. All this is done by the app in conjunction with the Shield Experience 8.2 firmware.
(FYI: We worked with Nvidia to get those issues resolved by getting them good samples and showing where the deficiencies were. They stepped up to the plate and did a super job.)
My reply is essentially – Choose a good player and, in this case, PMS will DirectPlay to it. When I do eventually get ATSC 3.0 (going to be a while for my provider), I will be ready.
One thing to consider: What’s the bitrate of that 1080p 60? Is it 15+ Mbps or is it still in the 5-7 Mbps range like most ?
Oh, I’m sure they will get some streams for initial testing. There are plenty of ATSC 3.0 test streams available but you know there’s nothing like a good long soak test sucking down multiple episodes of content and verifying no anomalies.
O yes I have many testing devices, including all Nvidia Shields:). I think it’s 13-16 Mbps, from the hdhomerun tech tool if I’m reading it correctly.
ATSC 3.0 files with AC-4 are easy to get, just ask and we can give whatever team member whatever amount of streams they want. And they will need some different ones to test as different groups of channels are doing something different (that is causing something that seems to be channel mapping problems with HDHR).
As the channels are max of 1080p and are mostly crammed together on one lighthouse, the bitrate that I see is around 3-8mbit for a single virtual channel. Just sampled CBS and the mpeg 2 1.0 channel was 10mbit and the HEVC 3.0 channel was 7. ABC 1.0 was ~6mbit and 3.0 was ~3.5mbit. My NBC 1080p channel isn’t working currently to check it but I would expect it to be a little higher.
