Nvidia Shield TV - Buffering Issues

Hi there,

I am having constant buffering issues watching live TV. Although I've done some research, I haven't found any solution to my problem. Below is an overview of my setup:

  • Nvidia Shield TVs, I have both the 2017 and 2019 models
  • A Sony TV with Android TV Built in
  • Orbi Mesh WiFi (WiFi 6 Model)
  • HD Homerun Prime
  • Synology Nas running the server package

HD HomeRun Prime Diagnostics

  • Cable Card Status
    • OOB Frequency: 104.200 MHz
    • OOB Lock: 2.048 Mbps
    • Signal Strength: 94% (-3.6 dBmV)
    • Signal Quality: 100% (38.1 dB)
  • Tuner Status (Example)
    • Signal Strength: 100% (5.6 dBmV)
    • Signal Quality: 100% (37.9 dB)
    • Symbol Quality: 100%
    • Streaming Rate: 3.969 Mbps

On average, when watching live TV and viewing stats I have about a .5 second cached and my stream rate fluctuates between 3 and 5 megs. I get much higher cache and stream rate values when watching a recording from the server and don't have any buffering issues. I'm not exactly sure what the problem is here. I feel my stream rate should be higher based on what I've read, but this is all new to me.

Any help would be much appreciated, thanks!

Is tuner sharing on? What does Settings > Support > Speed Test show?

Tuner sharing is off and the dvr speed test showed ~460Mbit/s.

How are the HDHomeRun and DVR server connected to the network? Are either of them wireless as well?

The are both connected to the 'router' of the mesh network through ethernet.

Can you do a test by connecting one of the shields by ethernet and see if the buffering ends? If not, it may be a transcoding limit issue. I'm not sure on a Synology NAS CPU performance for transcoding.

Do you have your shields set to 'original' under playback -> streaming quality so the NAS isn't doing any transcoding? 3-5mbps for a live stream sounds too low (unless you watching ATSC3). It should be 8-20 for an 'original'.

Edit: nevermind, I see you using cablecard and not OTA. So 3-5mbps may be normal for original content.

I could be wrong, but I was under the impression that there wasn't any transcoding for internal streaming. That said, CPU usage is near 0 and ram usage under 50% on my nas while watching live tv. I wish I knew what a normal stream rate was for cable card.

Try enabling tuner sharing and see if the behavior changes any. Even if it doesn’t improve, this will allow the DVR server to log what is happening so when the issue occurs share the logs details and it might help narrow down the issue.

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Depends upon the cable carrier. In my experience, H.264 encoded channels tend to have lower bitrates (3–6Mbps) than H.262 (MPEG-2) streams (5–8Mbps). Also, some streams will peak at 12Mbps, while others can hover around 2Mbps.

I think I'm getting mpeg-2 streams from Xfinity. With an average stream rate of 3.5 to 4 mb/sec.

Giving it a shot now.

Submitted a diagnostic log while turner sharing is on shortly after experiencing this issue.

Seems like symbol quality and bitrate are dropping to zero randomly.

Does the same issue occur in the official HDHR app?

Are you using any coax splitters or amps with your HDHR prime?

I haven't used the official app, well because it's kinda a pain to use IMO. I do occasionally use the live channels app and don't have any issues.

And yes, the HDHR prime is connected to a splitter amplifier. I had to add that as the HDHR was reporting a weak card lock.

I'd advise you to trace and document the coax line from the street to your prime. Figure out where all the splitters are, and make sure there are: as few as possible, they're all high quality, there are no unterminated ends (unused split points), and the cables used are all very thick and screwed in all the way.

If you can move the amplifier closer to the entry into your house that would probably improve the situation. Right now its just turning the volume up on a bad signal.

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tmm1 has good advice. Really, your cable card(s) should have 0 to 1 splits between them and the line into the house. Since they are feeding all your TVs, you have no reason to send your cable signal to each room. The only other device that would require a split is your cable modem. Usually, you can go to the cable box on the side of your house and open it up. It will probably have a 4-way splitter. Figure out which one is the line that feeds to your cablecard, and replace the splitter with just a grounding female/female connector to that one coax. If you do this, remove the amplifier, as you may over power the signal then.

That coax line to your cablecard could also have another split on it in the attic to share it between rooms. But if you go from a 4-way to a single as mentioned above, it wouldn't matter.

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I'll see what I can find out over the weekend. I want to say there's 2 splits before the HDHR Prime. I really don't know the difference between high quality and cheap splitter is. l'm guessing they were supplied by the cable provider at some point.

Thanks for all the advice on this! Like I said, this setup is all new to me.

I was able to trace the wiring yesterday. I found there were 2 splitters between the line coming from my house and the HDHR Prime. The splitter closest to my HDHR was a powered signal amplifier. I was able to temporary remove one of these splitters. This puts my setup at 1 splitter, plain ole normal splitter, between the main line at my house and the HDHR. The other end of the splitter is connected to my modem. I spent quite a bit of time testing yesterday, primary watching sports, and noticed the following:

-local channels, like fox, stream rate is much fast than other cable channels. These channels range from 5 - 7 mb/s. These are provided by cable provider, not OTA.

-other channels stream rate is about the same 2 - 4 mbs. Not much of a difference here, but slightly better.

  • I still get buffering with only 1 splitter with both local channels with higher stream rate and other cable channels. I submitted diagnostic logs this morning for each scenario.

My guess at this point is the signal coming into my house is just weak. I live at the end of my neighborhood. That being said, internet speeds are fast and I don't have any packet loss. I also had a new line put in, from the main box to my house, about a year ago.

I tried try some other apps, I'll be happy to list them if needed but the HDHR was one of them, for about an hour and didn't get any pauses or buffering during playback. I was actually surprised with how good the picture quality of the HDHR app. This totally throws off my assumption of a weak signal. That being said, neither of the apps have the features of channels.

Please don't take any of this as bashing or saying anything about this software. I really like it and it checks all my needs. I'm just trying to add as much info here as I can.

Once again, thanks for all the advice and assistance troubleshooting this issue.

The HDHomeRun has a web interface. Browse to its IP and when you tune channels you can look at the tuner details and it will give you detailed signal statistics. I was recently having an issue with my prime that was a real head scratcher. All channels on the 57 MHz frequency were weak, but all other frequencies were fine. Had Spectrum send out a tech and he had to trace it all the way from the wall to figure out the issue. It was an obscure one too. The tuning adapter that Spectrum provided has a pass through so I had the coax going out from that to the HDHomeRun. Turns out the signal was being dropped in that pass through. He added a splitter to bypass the pass through and now no problems.

I used to be a cable tech back in the day. Being at the end of a neighborhood or on a terminating tap doesn't make any difference. Not saying that you may not have a signal issue, you absolutely could. I'm saying that being on the end of a line doesn't automatically mean that.

In general you only need an amp to overcome signal loss. You should never need one to overcome a mainline issue like the signal is too low at the tap.
Let's say you have a 100ft drop from the street feeding a 4 way splitter. You are going to lose about 4.5db on the drop and then 7db on each leg of the splitter. So that's an 11.5db drop plus the length of cable from the ground block to each device. Take a 15db amp and you are close to net 0 on your signal. But... You should never just add an amp to overcome loss. The signal feeding your drop may be on the hot side and you may not need to overcome any loss. You have to look at your signal level to figure out if one is necessary. Also the amp should NEVER be placed behind the device, that just amplifies bad signal. You should also avoid multiple splits and never use gold plated radio shack splitters. I can't tell you how many of those I ripped out as a tech.

If the hdhomerun app doesn't give you the errors it's likely not a cable/signal issue.