ATSC 3.0 support - HDHomeRun Flex 4K

[DSperber]

The Spanish designation is from the source, NextPVR can't control that.  I am actually surprised that you need to hit the SAP button that often (AC-4 and other testing aside) don't most of your broadcasts in NextPVR come up with the principle audio track correctly?

If you have followed my posts on this thread, I have mentioned that there is PC based transcoding for AC-4 available in NextPVR should you need it.

Since you seem happy with obsolete tech WMC and the DMA2100's should be OK.  Those boxes couldn't even do h264 so I skipped them back in the day. 

Martin

Just to be clear, I have never and probably never will again need to actually use the SAP button... on ANY TV or device. Obviously English is the normal default language played and typically it is 2.0/5.1 as whatever the broadcaster sent. Perfect. Virtually all TV's and AVR-based audio systems can accept this, including down-mixing to stereo (e.g. if the TV only has two speakers but is able to accept a DD5.1 audio stream). SAP is of zero interest or value to me, normally.

The only reason it is "so important" this week is because of the "no audio" problem here in LA with ATSC 3.0 channels. And research has revealed it's because the LA broadcasters have placed the English DD5.1 audio on audio track #2, not track #1. And since the absence (at the moment, before hopefully getting fixed this week by a new firmware upgrade for the HDHR tuner hardware that will now correctly out the audio track language in the PMT/VCT so that the client apps can figure out which track the English audio lives in) of the language identity of the audio tracks causes the client to default to audio track #1 (which as it turns out here in LA is either Spanish-stereo, or silence, or who knows what low-quality English), that is why the SAP functionality is so important.

I, the user, need to be able to get sound along with video, and that means for the ATSC 3.0 channels being able to invoke the SAP feature so I can switch from audio track #1 to audio track #2. That's the ONLY reason I need SAP.

For ATSC 1.0 channels, where there is no firmware defect (I assume), the language of the audio tracks IS being sent out, so whichever imbedded audio track is the proper English track is automatically selected by the clients. No need for me to use SAP, clearly.

I was only experimenting further with how to get SAP, and to see if it did what it was supposed to, for ATSC 1.0 channels, just to see how it worked... if at all. It certainly doesn't actually work on the ATSC 3.0 channels (because of the AC-4 format preventing it from behaving properly), so I was using the ATSC 1.0 channels just to give it a look-see.


As far a PC transcoding audio from AC-4, I'm not sure I saw a description of that or how it is facilitated. But I will look back. I'm not sure it's really that important yet, since the workaround technique for this issue is seemingly satisfactory using HDHR instead of NextPVR, at least for the time being. And it's only for one channel, KTTV NX, and then only probably for very rare broadcasts.

I almost never watch Fox broadcast, so this all is largely theoretical as my "sandbox" for learning about ATSC 3.0, HDHR Flex 4K, etc.


As regards WMC, I've been using it since back in 2009... but just for TV. I know it had lots of additional "media" capabilities but I only wanted to replace my Time Warner cable hardware costs with my own whole-home solution. WMC was PERFECT as a TV service device, and DVR!! And it only had to deal with MPEG-2 and the resolutions of broadcast and cable, which were 480i,720p and 1080i. And for that it was 100% a success story... at least for me and my objectives. WMC supported NTSC originally, and I've had lots of different AMD TV tuner cards, hardware adapters to accept S-VHS feed for direct MPEG-encoding and viewing, etc.

That's why I opted for the Linksys DMA2100 as my extender (obviously the functional equivalent of today's "client apps" that run in smart and streaming devices) rather than the DMA2200, because I only wanted to deliver HDTV from the WMC HTPC throughout my house to the multiple TVs, and the extender was the required device in order to support copy-protected DRM content thanks to the deal MS made with Cablelabs for WMC to support recording as well as live TV of DRM-protected content.

From a software DVR perspective for me there are no complaints about WMC. And here it is 12 years later and I'm still using it, and Win7 HTPC's (obviously upgraded many times but always WMC). I mostly watch cable content (through my Ceton 6-tuner cablecard-enabled card, along with my Hauppauge Quad-HD 4-tuner OTA/ATSC card) and thats' why I knew I had to look to more modern hardware/software for OTA ATSC 3.0 support. It is essentially FLAWLESS, in the perfect rendition of exactly what it was designed to do. I don't care that it is no longer actively supported by MS. It still works perfectly for me and my needs.

But the WMC Guide design (now supported by EPG123 via Schedules Direct) and related supporting functionality... I mean it's perfect. Basic, but intuitive for ANYBODY to use immediately. Just like the basic functionality of the early DVR's and their user interface built by Motorola.

[mvallevand]

No need to repeat, I understand your issue. What I am saying is it is a noniissue since the only NextPVR client that supports AC-4 also supports SAP.

When you think you are ready to use NextPVR I can help you with the Extra https://forums.nextpvr.com/showthread.ph...ight=extra until then I don't think it is worth either of our time.

Martin

[DSperber]

Have you even tried the uidroid client on your Shield like we keep telling you to do? It should support selecting the audio track from any that are available. And, as I keep telling you, it will probably also support your ATSC 3.0 channels (both video & audio) natively.

To be honest I've never "side-loaded an app", which is part of the implementation of this client. But I really can't defend that position as a justification for not taking on uidroid. In all honesty this first week with the Plex 4K, HDHR software Win7/10 server and multiple clients, NextPVR Win7/10 server and multiple clients... it's been an awful lot of time spent. And lots of issues to chase and resolve. Not much sleep.

So, to begin week 2 I will make it my goal to install uidroid. I really do want the look and feel of the Windows NextPVR at the very least, so that should be enough of a motivation to dive in. And not to mention the other benefits pertaining to audio improvements especially for ATSC 3.0.

Hopefully SD will push out the firmware update which will address the language problem responsible much of this week's "no audio" resolution efforts.

I will get uidroid installed. I don't mind that's you're pushing me to try it... and probably like it.

[DSperber]

Have you even tried the uidroid client on your Shield like we keep telling you to do? It should support selecting the audio track from any that are available. And, as I keep telling you, it will probably also support your ATSC 3.0 channels (both video & audio) natively.

I will get uidroid installed. I don't mind that you're pushing me to try it, and probably like it.

Mission accomplished. It's now installed! I used ADB2Link installed on Windows to do the install of the APK downloaded/saved on my Windows PC, through the network and directly onto the Shield Tube.

And of course you were right. I DO like it. It is the Windows UI version of NextPVR.exe, but operating on my Shield tube.  Perfect. I now have the NextPVR Guide to browse and select through. Excellent!

And it does produce audio and video for the ATSC 3.0 channels as well as for the ATSC 1.0 channels. And as you predicted long-press up-arrow does bring up the dialog to select audio track.

Thank you for badgering me. And to Jocala Software for ADB2Link which made side-loading it onto my Shield Tube a trivial few minutes work.

One final question: how is it that AC-4 audio on the ATSC 3.0 channels is supported, as you say "natively"? I thought there was no AC-4 software codec available yet, so how is it that there is sound? There's no sound from the NextPVR ATV4K and Android Android clients. So how is it that this particular NextPVR UI client on Android is able to deliver sound? I thought the HDHR app variants (with its cloud-assisted transcoding) were the only way to get sound from any client apps at the moment, and not natively at that? So what am I not understanding?

[mvallevand]

I understand the thought that we were badgering you especially with 3 of us repeating the same mantra but we know that is what you wanted.

NextPVR doesn't do a perfect job of detecting details on the AC-4 tracks to present on the "long up" menu as it only does a general AC-4 but you should be able to see the audio track on long up. If you aren't seeing any tracks listed under Audio please provide a link to a one minute sample and sub and I can have a look. You can use OneDrive GoogeDrive or your local server.

Native support for AC-4 is only provided if your Android device supports AC-4, your Samsung S21 would be an example. Otherwise Exoplayer, the player uidroid uses, uses ffmpeg to decode several audio audio formats if they not natively supported eg. AC-3, MP3, FLAC, DTX. I used a patch for ffmpeg that added AC-4. Technically this is not "direct-play" but audio transcoding on 2021 devices is going to impact performance. I do remember a time years ago where even mp3 transcoding wasn't possible real time.

The patch for ffmpeg is work-in-progress but I expect there will be improvements over time. I don't believe ATSC 3 broadcasts offer any quaility benefits over ATSC 1 for video or audio at this point although HEVC will take less disk space then MPEG2video so most users are good for many years. Probably by then we will looking at 8K or beyond. I doubt most users will have the 18 speaker setup that you can get with AC-4 today (and that is just the start)

Martin

[DSperber]

Also via an Extra it is possible to transcode the AC-4 to AC-3 or AAC for more portability.

Martin

Can you please point me to where I can get detailed instructions on what I have to set, tweak, install, or configure, in order to accomplish this correctly and completely using whatever built-in NextPVR resources are available.

Is this functionally equivalent to the following, which copies input-TS to output-TS substituting AC-3 5.1 audio in the output for the original AC-4 5.1 audio in the input, while also just COPY'ing the HEVC video, through use of the AC4-modified FFMPEG?

ffmpeg.exe" -i "input TS file" -c:a eac3 -map 0:0 -map 0:2 -af "channelmap=0|1|4|5|2|3:5.1(side)" -vcodec copy "output TS file"

I'm not sure but I fear the use of FFMPEG will lose any DVR-installed metadata written by NextPVR at the start of the actual TS file when creating the recording. I'm just speculating here, because I believe HDHR recordings do have 64 packets (about 12K) of metadata at the start of its MPG files.

I'm still trying to get the complete instructions on how to do what you've suggested using NextPVR and and "extra device", instead of using the FFMPEG copy-approach.

[mvallevand]

First I wouldn't worry at all about ffmpeg if you do you command line properly I've been doing it for two year for many of my recordings and NextPVR uses it too for recording from some IPTV and for playback on the web server. It might even improve streams via the remux.

The beauty of using the transcoding Extra is it will play in all NextPVR clients but the web client won't like the HEVC/AC3 combination so it would be transcoded again.

If you go the Extra route, my suggestion would to keep channels < 100 as HDHR channels remove the 100+ and use the extra for 100+ For archival and quality recordings I would stick with ATSC 1.0 at least for now. I make this recommendation even if you are saving native AC-4 as an HDHR since it is still work in progress from the broadcasters. I don't even think closed captioning is working yet.

I know NextPVR detects the Flex 4K as a quad but I don't know how the 4 ATSC tuners and 2 ATSC 3.0 tuners work, I don't think you can use 6 at a time so you'd need to play around with that.

Better to followup on the discussion in the Extra forum here is the main extra https://forums.nextpvr.com/showthread.php?tid=62097 You are free to use whatever ffmpeg commands you like, it really was proof of concept anyway as there is no ATSC 3.0 here for me to test.

However since that post I would recommend that you try the ffmpeg from current Emby pre-release. Released without source (Emby doesn't respect open source) but it is the only way to create an mp4 from AC-4 that I am aware of. My linked ffmepg would be about the same as ferrels' and you can use either.

Also of note for this discussion I don't help users with ffmpeg commend lines. If you don't like mine you can experiment with the batch file and pipe it into ffplay to see how NextPVR will see it ie

hdhrconnect.bat | ffplay -

Martin

[garyysmirht]

The 100+ channels are bogus Silicon Dust channels.  I have suggested to sub to simply subtract 100 from the major number.

The NextPVR UI client uidroid should support HEVC and some level of AC-4 on most modern Android boxes that support HEVC.

Also via an Extra it is possible to transcode the AC-4 to AC-3 or AAC for more portability.  Unless you need HEVC and not H264 I don't think it is currently worth it.  Maybe when there is true ATSC 3.0 content things will be different.

Martin

Signcarver confirms what Martin and I have stated that SiliconDust is arbitrarily adding 100 to the channel numbers (provided by the broadcaster in the ATSC 3.0 stream) for ATSC 3.0 channels

[mvallevand]

It looks like broadcasters continuing their greed after successfully killing Locast.org are going to use DRM with ATSC 3.0 https://www.cordcuttersnews.com/tablo-wi...d-ota-dvr/ so NextPVR as a solution for ATSC 3.0 could come to an end.

Martin

[sub]

From what I've read, this is likely to be for "other" content. I'm guessing it'll be like ATSC-MH, where the spec covers the ability to DRM, but there is a whole lot of reason they never really use it except for select content.