Posts by nvdias

Quote from fatgerman

To add my voice to the mix I'm also noticing stuttering and juddering on Pi4, with newest LibreElec on videos with 5.1 audio in all formats (AC3, EAC3, and DTS). I'm using an external USB sound card and I do set the audio to 'Fixed' at 48KHz. This setup, and these videos, have been playing fine on a 3B+ for months.

I've also noticed that, sometimes when the juddering starts the audio channels suddenly get randomly mixed up - eg center becomes left, left becomes subwoofer, etc etc - this happens during playback and then it gets stuck like that. Sometimes even a reboot doesn't cure it. There's nothing whatsoever in the kodi log.

that is basically the same behaviour I've got.

Try forcing 4.0 audio output (or less) and confirm that Judder disappears.

(Stutter will continue on some subtitles - if you use them)

Yes. Ir works fine with Pi 3.

Waiting for new betas for pi4

Yes: There is some stuttering with subtitles (not with every subtitles. only some).

But there is a lot of stuttering if the audio conditions defined above (4 or more audio channels being sent to the tv) even without subtitles.

After some more testings I can do a very educated guess, that the video issues are really related to audio configuration !

I've previously said that disabling audio pass trough gives me a perfect video experience, but some of you could not confirm this.

So, I've looked deeper in this issue and found that:

a) If the audio output has 4.0 or more channels there are always artefacts in video. For both 23.976 and 25 fps (at a video output on 1920x1080).

b) If the audio output is less than 4.0 (2.0, 2.1, 3.0, 3.1), video plays perfect and smooth.

So, I'm now forcing 2.1 audio output trough HDMI and either video files and live-tv are playing great.

This is true for audio pass-trough enabled or disabled - of course that only with audio pass-trough disabled, you can guarantee the output format.

This is just a quick turn-around to help diagnose this "audio configuration that implies issues in video playback"

Quote from Klojum

This is still the news and announcements section. For support, please create your own topic(s).

You're right (I'm sorry).

Placed-it here: LibreELEC 9.2 beta 1 video judder and stuttering.

Thanks

EDIT [2020/04/29 - apparently solved ?]

EDIT [2020/04/29 - see here: LibreELEC 9.2.X video judder and stuttering [renamed]]

As suggested, I'm reposting my message originally in announcement tread:

I’m running LibreELEC-RPi4.arm-9.1.501 in my Rpi 4.

I’ve noticed that some video does not play smoothly.

There is judder, jerkyness and stuttering (lost frames?).

The odd thing is that no report whatsoever in kodi.log.

Butthe result is very unpleasant to watch.

It happens with 23.976fps material and also live-tv @25fps.

In the first case, kodi switches the tv to 23.976fps in the second one to 50fps (as it should be).

Kodi.log reports the correct fps switching.

But Looking to the video playback there’s a lot of strange motion artifacts, as if kodi is processing output to another fps different from the one it is outputting.

I have configured “Adjust Display Refresh Rate” as “start/stop”.

TURN AROUNDS:

a) In version LibreELEC-RPi4.arm-9.1.501 this seems to happen only if I have audio with “Allow Pass Trough” enabled. Disabling it, the video runs fine!

b) In version LibreELEC-RPi4.arm-9.1.002, I found a turn around by forcing “Adjust Display Refresh Rate” as “always”.

My TV is a SONY Android TV from 2016.

Note: I also have a RPi 3, with same configurations, in which all goes very smoothly.

Hope this can be fixed in the next releases.

Keep up the great work supporting the Pi 4

Quote from HypnoToad

More than likely has to do with the file. H264 and H265 are very smooth, but I've noticed with some old and badly/oddly encoded videos there is slight stutters. The pi doesn't seem to break a sweat on the codecs it supports via hardware. Have been thinking about just re-encoding things to h264.

Nope !

The exact same video files working great with pi3.

And it fails also in every live video channel ! (again: ok with pi 3).

And looking into other reports, it seems to be related to this release for pi4.

Quote from krobolbus

re: stuttery video playback on rpi4

I think I also found a workaround while fiddling with it.

It seems like this is somehow related to audio - when I set the audio output to analogue or hdmi+analogue the video playback is smooth, but when the audio output is set to hdmi only (which is the default) the video playback gets stuttery.

So:

I've noticed that disabling audio passtrough works ok.

krobolbus also had good response by forcing hdmi+analogue.

Someting at the audio processing level ???

(I hope this would help devs into the right way).

Quote from krobolbus

Video playback on rpi4 is still very stuttery as on the previous release ( LibreELEC (Leia) 9.1.002 ALPHA ) hope you guys will address this as it is pretty game breaking.

I’m running LibreELEC-RPi4.arm-9.1.501 in my Rpi 4.

I’ve also noticed that some video does not play smoothly. There is judder, jerkyness and stuttering (lost frames?) - The odd thing is that no report whatsoever in kodi.log – the result is very unpleasant to watch.

It happens with 23.976fps material and also live-tv @25fps.

In the first case kodi switches the tv to 23.976fps in the second one to 50fps (as it should be).

Kodi.log reports the correct fps switching.

But Looking to the video playback there’s a lot of strange motion artifacts, as if kodi is processing output to another fps different from the one it is outputting.

I have configured “Adjust Display Refresh Rate” as “start/top”.

TURN AROUNDS:

a)     In version LibreELEC-RPi4.arm-9.1.501 this seems to happen only if I have audio with “Allow Pass Trough” enabled. Disabling it, the video runs fine!

b)     In version LibreELEC-RPi4.arm-9.1.002, I found a turn around by forcing “Adjust Display Refresh Rate” as “always”.

My TV is a SONY Android TV from 2016.

Note: I also have a RPi 3, with same configurations, in which all goes very smoothly.

Hope this can be fixed in the next releases.

Keep up the great work supporting the Pi 4