Playing 4k video on RPI4, why does it transcode

Hi all,

I recently changed from RPI3B to a RPI4 because i would like to play 4k (home) video's.

I'm struggling to get some 4k content to play smooth on this setup.

I did a lot of reading of the forum

I'm using the Librelec 9.2.5. build for RPI4.

I connected the RPI via my AV receiver (Pioneer VXS 831) which is 4k capable to my Samsung q90r series TV (also 4k capable)

In my config I enabled : hdmi_enable_4kp60=1 (but I tested with and without this line with the same result in the end)

Apart from that it's unchanged after setup.

I use 1080p (30hz) for my desktop, and I whitelisted all the format my TV will take

I downloaded some 4k 2160p test content from this website (¦› 4K video test UHD trailers -Full 4K and UHDV 4k 60fps demo files-)

All of the content I downloaded does play on my TV set very nice when I put it on a USB HD and start it from the TV directly.

I notice that when I play via Kodi not all files play smoothly.

I take one example, this file: Downloads Page - Demolandia

It's resolution is 3840x2160 @29.97 Hz. This is a whitelisted resolution, and as said my TV accepts this.

It's H264 encoded.

When started via Kodi it stutters. When I call the on-screen info (see attached picture) it seems to me that Kodi is transcoding this video since one of the cores is running at 100%, all the time.

Why is Kodi doing this? It should be a supported resolution right?

Regards,

Johan

Quote from HiassofT

H264 hardware decoding is only supported up to HD resolution on RPi0-4. Only HEVC works with hw decoding of 4k files on RPi4.

But keep in mind that some of the high-bitrate 60fps HEVC demo clips won't play smooth (this is a known issue), standard 4k 24-30fps files should be fine though.

so long,

Hias

Ah, ok I did not know that. I will test a bit more than, looking for HEVC H265 encoded content.

regards,

Johan