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Increased BER, Uncorrected Blocks and Continuity Errors while EPG scan/grab

Added by Michael Wieland almost 7 years ago

In the last few days I noticed that the BER value, Uncorrected Blocks and Continuity Errors increase some time after EPG scan/grab is starting.

The EPG scan starts every day at 5:00 AM and today finished at 6:49 AM.

Tuner 1:

BER:

Uncorrected Blocks:

Continuity Errors:

Tuner 2:

BER:

Uncorrected Blocks:

Continuity Errors:

Any ideas why those value increase while EPG scan is running? All of them also decrease but after the EPG scan finished, the Uncorrected Blocks and Continuity Errors increase and stay at the same value till I manually clear the stats in the Tvheadend frontend.

I'm "OK" with Continuity Errors while switching the mux as this also happens while watching TV and changing the channel (it's not perfect, but that's something different). But why is there an increase in the BER value (whatever BER means?) and why are there Uncorrected Blocks. I don't have Uncorrected Blocks or an increase in the BER value while watching or recording TV.

btw. the graphs are generated by Check_MK/Icinga with a local check requesting /api/status/inputs.


Replies (13)

RE: Increased BER, Uncorrected Blocks and Continuity Errors while EPG scan/grab - Added by Michael Wieland almost 7 years ago

I've installed collectd and enabled the irq plugin. I will check what's happening once the next EPG scan is running.

RE: Increased BER, Uncorrected Blocks and Continuity Errors while EPG scan/grab - Added by Michael Wieland almost 7 years ago

OK that's weird, the IRQ values don't change much. Or collectd is collecting different data.

RE: Increased BER, Uncorrected Blocks and Continuity Errors while EPG scan/grab - Added by Michael Wieland almost 7 years ago

I'm using DVB-S2.

Tvheadend version: 4.2.4-30~g09eb70281
Tuner: Digital Devices CineS2 v6.5
Driver: ddbridge 0.9.32
OS: Debian 9.1 (Stretch) x64

I also have issues on switching a mux (i.e. changing the channel) on the same tuner and on another tuner (e.g. I can see artefacts once a recording starts and ends while watching live TV). This also leads to continuity errors. Maybe this is related and some type of driver or hardware problem?

RE: Increased BER, Uncorrected Blocks and Continuity Errors while EPG scan/grab - Added by saen acro almost 7 years ago

hardware problem can be power supply
lm-sensors can help

watch -cd sensors

next to check cable connectors and lnb

p.s.
update your TVHeadend

RE: Increased BER, Uncorrected Blocks and Continuity Errors while EPG scan/grab - Added by Michael Wieland almost 7 years ago

lm-sensors... you mean the CPU temperature could be a problem?

The collected data in collectd doesn't show any issues with the CPU temperature:

Also weird: Tvheadend reports only SNR of -13 dB. A "normal" satellite receiver reports both a signal strength and signal quality (which is the SNR?) of about 70%.

Previously I used the ddbridge driver included in the Debian kernel (I think it was version 0.5) which also reported the signal strength and SNR in percent. With the old driver I got an SNR of about 25% and signal strength of about 70%. Therefore I don't think it's an issue with the coaxial cable, F-connectors, LNB or the dish. Otherwise, the satellite receiver also would have an SNR of about 25%.

RE: Increased BER, Uncorrected Blocks and Continuity Errors while EPG scan/grab - Added by saen acro almost 7 years ago

lm-sensors monitor also voltages
voltage variations on
+3.3v
+5v
+12v
outgoing lines of PS

RE: Increased BER, Uncorrected Blocks and Continuity Errors while EPG scan/grab - Added by Michael Wieland almost 7 years ago

OK, I just correctly configured lm-sensors, now it also reports voltages. Let's see what's happening with the next EPG scan. :)

RE: Increased BER, Uncorrected Blocks and Continuity Errors while EPG scan/grab - Added by Michael Wieland almost 7 years ago

I just looked for the collected voltage values but they don't change much in the EPG scan time range.

RE: Increased BER, Uncorrected Blocks and Continuity Errors while EPG scan/grab - Added by Michael Wieland almost 7 years ago

I just realized that the IRQ values collectd writes are continuously increasing slightly. My collectd installation writes the data into InfluxDB and shows them in Grafana. So I just added the "difference" transformation function into my metrics query and there we go: There are changes in some IRQ values.

I've rendered all IRQ values of today 04:00 am till 08:00 am into separate images (as they have really different value ranges making it hard to show the tiny value changes) and omitted the IRQ values staying permanently at zero.

I don't know much what those values should say, so here you go: https://imgur.com/a/N3smf

RE: Increased BER, Uncorrected Blocks and Continuity Errors while EPG scan/grab - Added by Michael Wieland over 4 years ago

Rai Martins Ferreira wrote:

Hello how are you?, I saw your post and found it very interesting and ingenious, and would like help to connect my tvheadend to checkmk but I'm having difficulties, would you have any tutorial?

Currently I'm using a Python script as a local check for CheckMK which is executed by the CheckMK agent (usually located in /usr/lib/check_mk_agent/local). I've added my current version of the check as an attachment. As I'm using Tvheadend in a Docker container I'm using environment variables to configure the connection to Tvheadend (i.e. username and password).

check_tvheadend.py (6.41 KB) check_tvheadend.py

RE: Increased BER, Uncorrected Blocks and Continuity Errors while EPG scan/grab - Added by Gergely Cs. over 4 years ago

Wget / curl + some grep or json cli parser like jq does the job fine.
With munin it's easy, you just have to return a name:value pair and almost done.

I will do with my cards soon and if you interested i'll share the plugin script.

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