LibreELEC 9.2.X video judder and stuttering [renamed]

  • in Kodi settings, player, video. make sure expert is enabled. scroll down to find processing section and in there turn off or on the hardware acceleration

  • Thanks. That's this MMAL thing...


    It does the trick for now!


    Without mmal- HW decoding, video is much smoother and better regarding the sound, passthrough and subtitles problem.

    Thank you chitalov and Kramer!

  • I have also problem that some movies doesn’t play smoothly on pi 4b. But for now its only on 1080p files with VC-1 Format, 4K works fine. The sources are untouched, video as audio also.

    I could see, that in this moment the CPU usage was at the level 100-115%. So far its smaller then ~94% movie plays really smoothly.

    I’ve tried already with and without mmal- HW decoding. Also options with sync video to display.

    My audio is as pass-through but I also tried without it. It also doesn’t matter if audio is AC-3, DTS, DTS-HD etc.


    With license for hardware decode on my “old” pi 3b+ it works best.


    Version I’m using: LibreELEC-RPi4.arm-9.1.501


    have you some suggestions?

  • I confirm the problem with VC-1 at RPI4 running LibreELEC Beta 1. The playback is not smooth. Monitoring CPU usage, it is visible that one CPU core is running at almost 100%, while other CPU cores are idle.

  • The situation with VC-1 is getting clear. RPI4 decodes it by software. Kodi is using ffmpeg and its implementation is only single-threaded (see pending new feature #1885). So there isn't any easy way how to resolve this.

  • Same thing here with VC-1 decoding at 1080p. I don't have 4K material with VC-1 so can't test that.


    Is my understanding correct that the RPi3B+ (and lower) use hardware decoding for VC-1?

    Hence the license needed for it. Same with MPEG2?


    I tried MPEG2 but since it's just DVD source I guess software decoding is fast enough for that.

  • Doesn't look like it :(

    The move to 9.2 Beta 2 didn't solve the issue. Kodi that runs under Raspbian exhibits the same issue, judder/frame skips that are visible on 24p playback especially when external subtitles are in use.

  • Oh, so it's a Kodi problem, platform independent....can't find any threads in different Kodi forums. We should start reporting, maybe they haven't got a clue what's going on?

  • Besides the subtitle problem, 9.2 still has the stutter and judder with aac audio. AC3, Dolby and stereo are fine!
    Only solution that works is to switch to 2 channels and or let Kodi convert aac to ac3.
    Pi3 works still fine with Channels set to 5.1 and decodes AAC to PCM 5.1 which shows as "Multichannel in" on the AVR...

  • Same here with my new Pi4. Lots of studdering and audio drop out. If I turn of the subtitles and switch audio to 2.0 the playback is perfect, like on my old Pi3.


    Hope these issues will be solved with the next updates. Otherwise I thank all developers for the great job.


    Regards

    Chris

  • Hi,

    I had the same problem, with randomly mixed up audio channels with 5.1 settings and random stuttering not showing up as dropped or skipped frames, but smooth playback in 2.0 setting. This is a workaround for paththrough signals, but disadvantage is not havving 5.1 upmix for audio files.

    Regarding the subtitle stutter, this discussed e.g. in this thread or this thread

    It can be removed (at least for me) by adding the following lines to the advancedsettings.xml file:

    Code
    1. <gui>
    2. <algorithmdirtyregions>0</algorithmdirtyregions>
    3. <smartredraw>true</smartredraw>
    4. </gui>

    My question: Did anybody report the audio setting stutter problem related ro rpi4 to kodi/xbmc already? I looked at the issues on the xbmc github, but did not find anything related, so I'm wondering if anyone of the developers is aware?

  • Ha. This solution seems to be working for me too...Great, I love you..kind of ;-)

    Did anybody report the audio setting stutter problem related ro rpi4 to kodi/xbmc already? I looked at the issues on the xbmc github, but did not find anything related, so I'm wondering if anyone of the developers is aware?


    I only asked in the official Kodi Forum without answers.

    Seems this is the only entry in Githun Bug Tacker, but closed because of ignored rules
    KODI 18.5 playback still stuttering ONLY with subtitles · Issue #17001 · xbmc/xbmc · GitHub
    So there is no open issue.

  • Sorry to bump this old thread, but I am experiencing the same issue and maybe have some more data on it.


    Scenario A: If my Pi4 is connected directly to my projector, libreelec displays without issue and all video plays without any stutter. All playback/video/audio/etc settings as per a default install.

    Code
    1. > tvservice -s
    2. state 0xa [HDMI CUSTOM RGB lim 16:9], 1920x1080 @ 60.00Hz, progressive


    Scenario B: If I connect the same Pi4 to my AV amp (which outputs to my projector), it initially returns 'no signal' (though the sound plays through the speakers), requires a tvservice intervention, and then the same video, played off the same network drive stutters.

    Code
    1. > tvservice -s
    2. state 0xa [HDMI CUSTOM RGB lim 16:9], 1920x1080 @ 60.00Hz, progressive
    3. > tvservice --explicit "CEA 16 HDMI"
    4. Powering on HDMI with explicit settings (CEA mode 16)
    5. > tvservice -s
    6. state 0xa [HDMI CEA (16) RGB lim 16:9], 1920x1080 @ 60.00Hz, progressive

    Obviously, I'd like to be running Kodi through my Amp. Any suggestions? It seems like the video stutter in this case is connected to what the HDMI is connected to..


    EDIT:

    I've since shifted over to Raspbian Buster with Kodi manually installed, and while I have the same issue with having to manually intervene to get tvservice to output a working HDMI signal, there are no video stuttering issues on 720P/1080p x264/x265 files I was seeing on libreelec.

  • Ok, some updates.


    Setup: RPI4 -> HDMI -> AVR -> HDMI -> TV


    Libreelec 9.2.1: The subtitle stutter seems to be gone for me as far as i can see? But maybe i was just lucky with the files i tested.


    BUT while h264/h265 (1080p) generally work i get weird "image bugs" regularly on those files now. They consist of:

    * Weird tearing for 1 second

    * Black screen for 1-2 seconds (while the audio continues fine)


    Those "hiccups" happen multiple times (Edit: was an understatement, correct is every 4-5 minutes) in a film/episode and it is getting pretty annoying. I will try to capture the errors in the debug log but last time i tried there were no noticeable entries while these errors happened. That makes it kind of difficult to analyze...


    Anyone of you also experiencing this?


    Edit2: The hiccups happen exactly every 5 minutes when "adjust framerate" is on (so the movie plays correctly at 24fps)

    When i turn that off and force 60fps constantly everything is fine (enough).

    Edited 2 times, last by gierthi ().

  • in Kodi settings, player, video. make sure expert is enabled. scroll down to find processing section and in there turn off or on the hardware acceleration

    I did this but all my .mkv videos still show “Hardware decoding: Active”. What’s the deal?