Experiences with Raspi3, Libreelec, Tvh4.2+HDhomerun

cubrilec · July 21, 2016 at 10:18 PM

Hi There!
After using Mediportal since years i switched to an Raspi3 with an HDhomerun eu DVB-C tuner (and DVB-t, but i only use dvb-c) . I am situated in germany.

I installed Libreelec on an 8gb SD Card (Ultra sandisk) activated tvheadend 4.2 as service and PVRclient.
First i had problems with stuttering, after using the official software for the HDhomerun and rescanning all channels with it (under windows), i got a much bettter result.
But it was not perfect:

1. i had every 10 to 15 min a short stutter in video (pixelation and so on)
2. When audio passthrough was activated, it showed audio stutter (audio was going suddenly very quiet and then going back to normal every 5 or so minutes)

Then i tested the timeshift feature, i activated in tvheadend (throug webpage) and started watching tv. I got the above mentioned stutter in video and audio.
Then i pressed pause, started watching again after 10 min or so and since then i experinced perfect sound and pictures since hours.

Great!

Has anybody an explanation for that? I know, i need to test this further, but i was excited and used that energy to write about it here
Grüße

Cubrilec

**popcornmix** · July 22, 2016 at 5:13 PM

There is a complication with live streams (like PVR) that the clock of the backend is probably not synchronised with the clock of the frontend.

The clocks will typically be driven by a crystal oscillator with an accuracy of around 100ppm (0.01%).
If it turns out that the frontend clock runs 0.1% faster than the backend, the amount of buffered data will gradually deplete until it is empty and kodi will pause to buffer again.

It is possible you are hitting this issue and by pausing you are giving more time before the buffered data runs out.

The good news is that if this is your issue then Kodi Krypton has a solution for this (audio resampling is used to manage the amount of buffered data, so synchronising the backend and frontend clocks).

You could try a LE 17 Kypton alpha build, or a Milhouse nightly build to see if the issue is still present.

cubrilec · July 23, 2016 at 8:03 PM

Thanks for the answer:

I have the frontend (client) and server on the same raspberry. Does the clock problem also exist then?

cubrilec · July 27, 2016 at 8:49 AM

So i had the chance to test the LibreELEC (Krypton) v7.90.003 ALPHA version of libreelec and the stuttering is much better there. I could watch 30 min without it, and get 1 or 2 times stutter per hour.
I also had a crash of the whole system when switching channels, but this could be because of the beta version...

So i hope the best for the new version.

cubrilec