[mythtv-users] Unusually high CPU utilization with DTS-HD MA

[Adam Stylinski]

I replaced my GPU with a new one that supports HDMI HBR passthrough
and replaced my old audio receiver.  In doing so, after successfully
passing through DTS-HD MA to the receiver I noticed some strange
stuttering that I hadn't before.  At first I thought it was a
buffer/IO issue that could be mitigated by adjusting the
vdpaubuffercount variable, but after further testing it wasn't IO
related.  I noticed that whilst sending the DTS-HD audio to the
receiver the CPU utilization was substantially higher despite the GPU
doing the decoding (this is H264 video playback from a Matroska
container).  Switching the audio tracks to a non-HD audio track such
as regular DTS yielded very low utilization (< 10% on both CPUs, where
the CPUs were performing the deblock filtering).  Switching this again
back to DTS-HD the CPU utilization again spiked (on one core).  The
load is not steady, it is variable, but it peaks at 100% utilization.
Is this normal, and is there a fix for it?