What format to play 4k media file on Samsung UBD-K8500 Blu-Ray player?

[jpank]

I downloaded this 4k youtube video using "youtube-dl RK1K2bCg4J8". The video format appears to match one of the formats that K8500 manual says they support. But the format is not recognized when I try to play it. I put the video file on an external drive connected via USB to the K8500.
The K8500 manual says it supports: *.webm WebM, VP9 3840X2160, 60 fps, 40 Mbps
Running ffprobe on the .webm file, I see:
Input #0, matroska,webm, from 'Breathtaking Colors of Nature in 4K III Beautiful Nature.webm':
Metadata: encoder : google/video-file
Duration: 02:10:05.20, start: 0.000000, bitrate: 15649 kb/s
Stream #0:0(eng): Video: vp9 (Profile 0), yuv420p(tv, bt709), 3840x2160, SAR 1:1 DAR 16:9, 29.97 fps, 29.97 tbr, 1k tbn, 1k tbc (default)
Any idea why this file is not recognized by the K8500 player? It only contains a video stream, no audio.
Thanks for any insight.

UPDATE: I tried different formats. I copied the VP9 stream into a .mkv container and now it played. Then I noticed that my original .webm file no longer had the red circle with a red line through it. When I clicked on it now, it played! But when I downloaded other short 4k videos from youtube, they all had the red-circle/line around them.

Now I need to work on getting audio to also play. I downloaded an audio stream for that same video using "youtube-dl -f xxx"
Fist I tried format 398 mp4 audio only 720p 1562k , 30fps, 998.55MiB
but I had errors merging with the video.
Then I tried format 251 webm audio only DASH audio 141k , opus @160k, 123.06MiB
I was able to merge this, but when I tried playing it on the K8500, it gave an error. (I believe "unsurpported codex")
I did the merging using, for example: ffmpeg -i "audio.mp4" -i "video.webm" -c copy combined.mkv

[sneaker]

Try AAC (-f 140) or Vorbis (-f 171) audio.

[jpank]

@sneaker - Thanks, Vorbis "-f 171" worked.