I’ve had a problem with LiveTV stuttering ever since receiving my Vero4k+
By stuttering, I mean that for a second or so the playback (Video and Audio) stops, and I see the spinner in the middle of the screen; then playback starts back up again. There are no artefacts or errors in the TVHeadend Server logfile. Sometimes it will stutter a few times in a row, sometimes just once. I can normally get it back to normal by switching channels back and forth.
I am using the pvr.hts plugin, which is connecting to a Debian Stretch Server with TVheadend 4.2.5
I have used TVHeadend on this server for the past 2-3 years without these stuttering problems on other clients.
The TVheadend server has 2x MyGica T230 DVB/T2 USB sticks (for Freeview), and 2x DVBSky S960 DVB/S2 USB adapters (for Freesat).
The stutters occur more frequently when tuning to Freesat channels (i.e. using the DVBSky S960 adapter) - these appear to have higher bandwidth and an additional narrated audio track.
I have no problems whatsoever when playing back recordings, it only affects playback of LiveTV.
I am also running kodi on an PRi3 in another room, with latest stable LibreELEC v8.2.5 - PVR live playback is flawless on this machine
After alot of testing, I seem to be able to reduce the stuttering with the following settings:
- Sync playback to display: disabled
- Adjust framerate: “Always” (Note: have also tried “On Start/Stop”)
- H/W accelleration set to “always” for all codecs
- Fallback framerate set to “off” in PVR settings - have also tried setting to 50Hz
I have a soundbar connected via SP/Dif and have enabled the Mute HDMI Audio option.
I have tested with both -119 and -121 (video improvements) kernels (https://discourse.osmc.tv/t/testing-vero-4k-4k-video-improvements) both have same issue
After reverting the video improvements kernel, I still get occassional stutters but they seem less frequent.
I have tried iperf3 tests between Vero->TVHeadend Server - results are good both ways ~900Mbps (ran a test for 30 minutes)
Have tried various tweaks to the TVHeadend settings - Status Period, Input Buffer, Use Packet Backlog (none had any effect - though decreasing the Status Period made things worse so i set it to the maximum 8000ms)
When problem occurs I see the following error in kodi.log:
WARNING: CRenderManager::WaitForBuffer - timeout waiting for buffer
There was no other traffic on the network whilst performing the tests
I’m starting to wonder whether the Gigabit adapter in the Vero4K is a little too fast, causing the buffer under-runs - i.e. it’s grabbing the data too fast.
I’ve posted debug logs when I reproduced the problem this morning on the -121 video improvements test kernel are here: https://paste.osmc.tv/nuhicozara
The times I hit the stutters with debug logging enabled were
This afternoon I have tried adding an Audio Stream filter in the TVHeadend Config to strip out the narrated (nar) streams, which seems to have reduced the stuttering - in 2 hours I only had two occurrences, but I still get the odd stutter.
Any thoughts on what to try next?