AC3/DD audio transcode causes glitches in video
I have an Amazon Fire TV Stick gen 2 (it replaced a gen 1).
For reference, the Fire Stick is plugged directly into an Onkyo AVR which supports DD, and DD+.
On the gen 1, I could stream my MKV DVD rips with no transcoding. Because of the on-going issue with Plex on the Tv Stick 2, I've had to turn off DD support. This forces plex to transcode the audio, which my AVR processes as PCM.
Most of the time this works fine. But on some DVDs, some scenes become quite pixelated as if some kind of processing effect is in play. If I turn DD support back on, the video is fine. Either way, Plex tells me that there is no video transcode going on.
An example DVD where this happens is the BBC adaption of 'Emma'. It happens quite a lot in the first 2 minutes of the first episode for example.
I should also say that the plex server is running on a PC with a Core I5 7600K and 16GM RAM. The MKVs are on a Synology Diskstation. The PC and diskstation are connected over ethernet. The Fire TV obviously uses WiFi - 5G with a very good signal, and can stream 130mb/s.
Anyone got any thoughts?