Playback deadlock

During playback, it seems that if the user asks for the next playback item it deadlocks.

Reproducible with Life_of_ Pi_draft_Ultra-HD_HDR.mp4 which you can find on Quincy: smb://Quincy._smb._tcp.local/Public/Samples/samples/HDR/Life_of_ Pi_draft_Ultra-HD_HDR.mp4

Backtrace:

https://pastebin.com/9gVH80h6

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