Can I get Serviio to index and play this file?

I just got myself my first 4K TV but as my internet connection is only 11Mb it isn't fast enough to stream 4K content so I downloaded some 4K videos from youtube and was intending streaming them from my NAS. They weren't showing up on my renderer so I looked in the serviio.log file and saw this message:
I have Serviio running on a QNAP TS-251+ Intel 64 bit NAS. I've updated all the ffmpeg files I could find to version 5.0.1 including the one in the Serviio home directory but the error persists. I was able to use Handbrake to recode the file but that took 80 minutes for a 5 minute video so that's not a feasible solution going forward. So two questions; is it possible to get Serviio to index and play this file (file details below) or if not is there any quicker way to recode it so that it does index and play?
Thanks,
Steve
- Code:
- General
 Complete name : \\NAS3AC9F7\Public\Video\Movies\LG 4K Demo - Slam Dunk in Dolby Digital.mp4
 Format : MPEG-4
 Format profile : Base Media
 Codec ID : isom (isom/iso2/mp41)
 File size : 520 MiB
 Duration : 3 min 14 s
 Overall bit rate : 22.4 Mb/s
 Movie name : LG 4K Demo - Slam Dunk in Dolby Digital
 Performer : The 4K Media Group
 Description : LG 4K Video - Slam Dunk in Dolby Digital is a promotional 4k demo video made by LG for the LG 4K UHD TV.
 Recorded date : 20190803
 Writing application : Lavf58.29.100
 Comment : https://www.youtube.com/watch?v=P9JrhuC-RfY
 LongDescription : LG 4K Video - Slam Dunk in Dolby Digital is a promotional 4k demo video made by LG for the LG 4K UHD TV.
 Video
 ID : 1
 Format : AV1
 Format/Info : AOMedia Video 1
 Format profile : Main@L5.2
 Codec ID : av01
 Duration : 3 min 14 s
 Bit rate : 22.0 Mb/s
 Width : 3 840 pixels
 Height : 2 160 pixels
 Display aspect ratio : 16:9
 Frame rate mode : Constant
 Frame rate : 60.000 FPS
 Color space : YUV
 Chroma subsampling : 4:2:0
 Bit depth : 8 bits
 Bits/(Pixel*Frame) : 0.044
 Stream size : 511 MiB (98%)
 Title : ISO Media file produced by Google Inc.
 Color range : Limited
 Color primaries : BT.709
 Transfer characteristics : BT.709
 Matrix coefficients : BT.709
 Codec configuration box : av1C
 Audio
 ID : 2
 Format : AAC LC
 Format/Info : Advanced Audio Codec Low Complexity
 Codec ID : mp4a-40-2
 Duration : 3 min 14 s
 Bit rate mode : Constant
 Bit rate : 384 kb/s
 Channel(s) : 6 channels
 Channel layout : C L R Ls Rs LFE
 Sampling rate : 48.0 kHz
 Frame rate : 46.875 FPS (1024 SPF)
 Compression mode : Lossy
 Stream size : 8.96 MiB (2%)
 Title : ISO Media file produced by Google Inc.
 Language : English
 Default : Yes
 Alternate group : 1


