Using HDhomerun I posted over at there forum and got this message back :
Well I am back LOL I was using Raspberry Pi-3 OSMC 17.6 Zoltan HDhomerun addon and noticed audio is out of sync on channel 247 which is Antenna TV on Comcast so to check if its Comcast I used my WMC to see if it works and on WMC-7 the audio is fine. Next test I used your zuki.pvr.hdhomerundvr-raspbian-armhf-krypton-1.3.13.6982 to see if it works and same thing audio is out of sync so both addons are doing the same. So its not only you Zoltan has the same problem
Both this PVR and Zoltan’s use Kodi (ffmpeg) for all decoding/demuxing of the streams. I’ve seen a couple Issues on the Kodi GitHub about similar problems (Issues · xbmc/xbmc · GitHub). Unfortunately Krypton development has ceased beyond version 17.6, so it’s going to be hard to get any type of resolution to it on that baseline, at least from Kodi. OSMC may be able to help.
Your best bet here is probably the Kodi/OSMC forums, my understanding of ffmpeg is very limited. It’s possible without a DVR account to record from the HDHomeRun tuners, having a sample of the raw stream will likely be needed as well for somebody to be able to triage the problem.
Sorry I don’t think I can be of much help to you on this one. The PVR addon is a go-between, it takes the data from the tuner and hands it to Kodi/OSMC unmodified. What Kodi/OSMC does with it … above my pay grade