There's some sort of performance/latency problem - you are getting a 'Dropping sample from the past' messages in the evr.log periodically.
The audio dropouts probably tie in with the 'Pause 195 mS renderer clock to match provider/RTSP clock' messages - these are because TsReader is running out of data in the timeshift file (the playback 'clock' - which comes from the audio renderer - is probably running slightly faster than the broadcaster clock, so after a while TsReader has to pause the playback to allow things to catch up).
Try pausing TV for a few seconds at the start and see if that helps.
Tony
Thanks. I'll try that and see.
I'm pretty sure I've got the latency under control at the moment as I've monitored it on and off over a few days and the kernel latency, ISR and DPC execution times have all remained within acceptable limits. I'll double-check it again though.