RPi LibreELEC fails to play VP9 codec in mkv file

simpz · June 11, 2018 at 11:17 PM

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.

simpz · June 11, 2018 at 11:30 PM

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

**smp** · June 12, 2018 at 12:01 AM

It plays fine on Rpi3 with LE 9 (current Milhouse build).

simpz · June 12, 2018 at 2:21 PM

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?

**smp** · June 12, 2018 at 2:29 PM

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.

**Iridium** · June 12, 2018 at 2:42 PM Official Post

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)

ozkaradag · June 12, 2018 at 3:07 PM

Greetings,

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

There are even some versions of Amlogic s905 chips.

Best regards...

simpz · June 12, 2018 at 4:10 PM

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

**Iridium** · June 12, 2018 at 5:52 PM Official Post

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.

FeFiFoFum · September 3, 2019 at 5:53 AM

VP9 and AV1, in Raspberry Pi 4? 2022? (shrug)