[mythtv-users] HDHomeRun tuners and network switches

[Hika van den Hoven]

Hoi James,

Thursday, January 20, 2022, 2:51:31 PM, you wrote:

> I'm trying to fix some issues with mythtv having breakups in the
> signal that could be a number of things like antenna placement,
> original signal quality, or networking issues.


> My production mythtv backend is using a WinTV quadHD PCI3 tuner
> card and I generally don't have issues with those recordings.  It's
> always the HDHomerun tuners that are connected to a test backend.


> I watch either backend using FireTV 4K sticks or Nvidia Shield TV
> with the mythfrontend and Leanfront apps. So lots of networking
> potential problem areas.  All of the streaming devices and backends
> are wired with either CAT5e or CAT 6 cables.


> I have at the top of the tree a TP Link AX50 WiFi 6 AP/router. 
> Each of the ports are connected to 8-port GbE switches in other cabinets or rooms.


> The problem got bad enough this morning that I decided to dig
> deeper into the situation.  While watching the recorded morning
> news, the picture kept pixelating with lost sound a lot more than is
> tolerable.  I checked the HDHR tuner with their signal app and the
> quality and stability of the signal looked great.


> The Shield TV and mythtv test backend that was recording the
> program are on the same switch 1 in a cabinet and the HDHR tuner was
> connected to another switch in another cabinet.  So I moved the
> cables around so that one of the GbE switches had the HDHR, mythtv
> backend, and the cable running to the cabinet with a switch for the
> streaming devices. This seems to fix the issue.  However if the
> cable going to the streaming devices is plugged into the switch
> above then I have issues. An attempt at a schematic below to make it clearer.


AP-router----->> switch 1 in closet (test mythtv-backend, HDHR tuner)
>                |-----> switch 2 in closet
>                |-----> switch 3 in cabinet with streaming devices (FireTV, Shield)


> The above has the most break ups when watching


> However, moving the cable leading to switch 3 from the AP/router to switch 1 seems to work best.


> Does this make sense or point to a problem?


> Jim A

This is probably a recording issue. The suspects are:
1. The hdhr power supply
2. The available network bandwidth. Try connecting to a dedicated nic
   on the backend. This however requirs you to setup a dhcp server on
   that backend
3. The available disk bandwidth

To check if it is not a playback issue, try playback on the backend
or a frontend connected to the same switch as the backend while there
is no recording activity. However bad playback connection would give
stuttering not pixelation.







Tot mails,
  Hika                            mailto:hikavdh at gmail.com

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