Transcoder settings- Best Practice ?

[klyneshouse]

Being a recent convert from WMC, I appreciate the no nonsense setup, but there are a few things I am not understanding.
The transcoder settings were originally set to NVIDIA, as the back end has a GTX970 on a current Win10 installation.   
Is there other things i am missing to properly use NVIDIA transcoding ? Is it even worthwhile ? 


When ever trying to use the NextPVR player on PC's,Shield etc, i always got Streaming Failed (transcoder exited).
When set transcoding to CPU, all the NextPVR apps now play, (except ATSC 3.0 channels still get Streaming Failed (transcoder exited)).


Normal use is the NEXTPVR backend, RPI/Kodi frontends, with TV/Cable HDHR tuners, and has been quite reliable for months.
I am even able to watch (just not listen to AC-4 audio)  to ATSC 3.0. 

Thanks in advance for any direction/ insight ! 


  

[sub]

Transcoding is largely used for when you're viewing in the web app, or in some cases on Android/iOS. Other types of clients typically do directplay of the stream and no transcoding is required. In the app on your Shield, you should be able to enable direct play.

ATSC 3.0 support is probably going take a little while. We're dependent on decoders, and ffmpeg etc being updated to support the AC-4 audio codec. I have heard about progress on that front, so it will happen.

[mvallevand]

I don't know what version of Exoplayer the Android App has but some Exoplayer versions do support AC4 with direct play. The Shield doesn't support it though you'd need to pass through an appropriate device like Samsung or LG phones. It might work with sub's Apple TV app on the 4K, but it doesn't seem to work on eariler versions.

The huge downside with ffmpeg and the Shield is enabling transcoding for everything. Hopefully one day NextPVR will have a transcode audio only option.

Martin

[klyneshouse]

Thanks for the explanation on directplay versus transcoding.
So for 99% of my viewing, since done on a Kodi client, then the transcoding setting is not really important if I am understanding correctly.
Since "CPU" setting results in the most functionality, then I will just leave it as is.

ATSC 3.0 is just hobby at this point, the few stations out there are still at 1080 so its not mission critical by anymeans.
The Shield + HDHomerun app will play AC-4 audio through an 7703 AVR. But the video is jerky and unwatchable.
While the NextPVR > Kodi video is nice and smooth and will run for days, even on a RPi-3.
So when the ffmpeg/AC-4 gets sorted it will be happy times.

[sub]

So for 99% of my viewing, since done on a Kodi client, then the transcoding setting is not really important if I am understanding correctly.

That is correct. With kodi it doesn't use transcoding.

ATSC 3.0 is just hobby at this point, the few stations out there are still at 1080 so its not mission critical by anymeans.
The Shield + HDHomerun app will play AC-4 audio through an 7703 AVR. But the video is jerky and unwatchable.
While the NextPVR > Kodi video is nice and smooth and will run for days, even on a RPi-3.
So when the ffmpeg/AC-4 gets sorted it will be happy times.

I have seen confirmation the ffmpeg guys have started looking at this, so only a matter of time.

[mvallevand]

There's a ticket on ffmpeg http://trac.ffmpeg.org/ticket/8349 so yes it is active so it might be ok when ATSC 3.0 is more widespread, but I think years not months.

I don't see it in Kodi Matrix most ffmpeg devs don't even good samples and when I uploaded a sample to the Kodi PVR devs there was no interest.

For NextPVR web HEVC is also a big problem for direct play on many platforms until browser support it. Maybe AC3.0 will force browsers other the Safari to have built in support for "newer" standards.

Martin

[mvallevand]

I was quite wrong about the timeframe. I just compiled ffmpeg with a recent patch submitted with AC4 support and ffplay seems to work nicely. From a NextPVR user perspective. It is hard to extrapolate from one file but this ffmpeg did work to convert 5:1 audio to 5:1 ac3 for audio purists.

Stream #0:0 -> #0:0 (copy)
Stream #0:1 -> #0:1 (ac4 (native) -> ac3 (native))

So it seems like an extra for ATSC 3.0 is already possible.

Martin

[ferrels]

I was quite wrong about the timeframe. I  just compiled ffmpeg with a recent patch submitted with AC4 support and ffplay seems to work nicely.  From a NextPVR user perspective.  It is hard to extrapolate from one file but this ffmpeg did work to convert 5:1 audio to 5:1 ac3  for audio purists.

Stream #0:0 -> #0:0 (copy)
Stream #0:1 -> #0:1 (ac4 (native) -> ac3 (native))

So it seems like an extra for ATSC 3.0 is already possible.

Martin

I completed a successful MSYS2 x64 build of ffmpeg that supports AC-4 audio streams and everything is working great for ATSC3.0/AC4 streams in the greater Phoenix area. For those who want to run the binaries outside of the MSYS2 shell, you will need to copy the following DLL files to the folder where your ffmpeg binaries ultimately reside.

They are:
libbz2-1.dll
libiconv-2.dll
libintl-8.dll
liblzma-5.dll
libstdc++-6.dll
libwinpthread-1.dll
libzstd.dll
SDL2.dll
zlib1.dll

On my system these DLL's are located in: C:\msys64\mingw64\bin

For those who want to conduct their own build, you can get the source for the AC-4/WIP here: https://github.com/richardpl/FFmpeg/tree/ac4

For those who don't want to build from source, you can download the Windows binaries from my DropBox account here: https://www.dropbox.com/s/eene7ecard5xk ... 4.zip?dl=1

An example command to play channel 161.1 here in Phoenix follows: C:\ffmpeg\bin>ffplay -i "http://192.168.2.142:5004/auto/v161.1?transcode=native" 
Substitute the IP address above with the correct IP address for your HD Homerun Tuner.

For those who used my binaries and experienced stuttering video and the VQ dropping to 0 after a few minutes of streaming an ATSC3.0 channel, add the "-sync video" and infinite buffer 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

[mvallevand]

@ferrels I posted my static compiles here https://forums.nextpvr.com/showthread.ph...#pid551326 a few weeks ago. I have Ubuntu and Debian builds too.

Note you can use that linked feature or your build with that addon and get ATSC 3.0 playback from the HDHR on any NextPVR client that supporst HEVC including Kodi. Live TV and tecordings are transcoded to AC3 It seems that no HDHR users were interested though.

Martin

[ferrels]

@ferrels I posted my static compiles here  https://forums.nextpvr.com/showthread.ph...#pid551326 a few weeks ago.  I have Ubuntu and Debian builds too.

Note you can use that linked feature or your build with that addon and get ATSC 3.0 playback from the HDHR on any NextPVR client that supporst HEVC including Kodi.  Live TV and tecordings are transcoded to AC3  It seems that no HDHR users were interested though.

Martin

I was hoping for a means to schedule ATSC3.0 recordings WITH audio so thanks for creating a method to do so.  I'll have to test it and give you some feedback if I encounter any errors.  Ultimately it would be nice to see AC4 audio baked into NextPVR or even VLC natively.  I may take a stab at building VLC with the AC-4 tree but the build process for VLC looks to be pretty daunting.