RPi LibreELEC fails to play VP9 codec in mkv file

  • A friend of mine passed onto me that he has problems with LibreELEC playing on a RPi2, with the HW codec keys installed (if that's relevant), a mkv container file with VP9 and OPUS inside.


    The same issue occurs on my install (and has done for a number of releases), I'm running 8.2.5.


    The symptoms are the video plays very slowly (practically frame by frame) and the audio initially sounds normal, but seems to get upset eventually.

    There is nothing in the log file that is complains during this playback. The file plays fine on VLC.


    Any ideas? I'll try and attach an example file or link to it.

  • Here is a on expirebox


    mediainfo is:


    Unique ID : 68295835849727551218027313336917870918 (0x33614CAE4286A9C467DD0FDAE526C946)

    Complete name : file.mkv

    Format : Matroska

    Format version : Version 4 / Version 2

    File size : 184 MiB

    Duration : 10 min 5 s

    Overall bit rate : 2 552 kb/s

    Writing application : Lavf57.41.100

    Writing library : Lavf57.41.100


    Video

    ID : 1

    Format : VP9

    Codec ID : V_VP9

    Duration : 10 min 5 s

    Width : 1 920 pixels

    Height : 1 080 pixels

    Display aspect ratio : 16:9

    Frame rate mode : Constant

    Frame rate : 29.970 (30000/1001) FPS

    Language : English

    Default : Yes

    Forced : No


    Audio

    ID : 2

    Format : Opus

    Codec ID : A_OPUS

    Duration : 10 min 5 s

    Channel(s) : 2 channels

    Channel positions : Front: L R

    Sampling rate : 48.0 kHz

    Compression mode : Lossy

    Language : English

    Default : Yes

    Forced : No

  • Interesting, do you have the HW codecs installed.


    I guess the answer might be to wait until 9 comes out? Unless anyone can verify on 8 or if you can think of anything else you have done that might be making this work for you and not us?

  • The HW VC1 and MPEG-2 codecs are irrelevant. VP9 is decoded with ffmpeg on Rpi. The performance of software decoded VP9 and HEVC is massively improved in Kodi 18.

  • The video requires considerable CPU resources. On my RPi3 (8.2.5) it was using 100% on all 4 cores.


    On LE9 it plays, but still uses about 60% on all 4 cores.


    So your best bet would be to decode it to something else (If you have a more powerful machine)

  • Greetings,


    Because there is no hardware support for RPI's VP9 code.

    There are even some versions of Amlogic s905 chips.


    Best regards...

  • Thanks for the information, I guess the issue is simply lack of cpu speed. Sounds very possible.

  • To be factual, it's a lack of hardware support for that codec as ozkaradag mentioned, so the decoding has to be done in software and that's where the CPU usage comes in, as the video has to be decoded in software on the fly - which is why it stutters.


    You could try a LE9 Milhouse build, but even at 60% usage you might still suffer from stuttering if you have any other processes running (TVHeadend etc) Also you'll need to keep an eye on the temperature as well.