[mythtv-users] Raspberry Pi - Audio Passthrough

[rob e]

> i finally got around to checking this out...and with both peter's and curtis's
> builds, audio is perfect...but only on some channels:-( the 2 local pbs stations
> (weta26 & wmpt22) just now were both showing antiques roadshow, so i could
> compare (supposedly) identical feeds: both 1080, but 26's sound breaks up badly
> while 22's is fine:-\
>
> turning off stereo upscale cures the breakup, but it's quite muffled:-\
> w.a.f->0

For me those sorts of problems appeared to be RAM related.
Each time the audio stuttered there was a "kworker" thread dominating CPU.

You might want to
(a) stop any unnecessary tasks / processes running (at bootup ?)
(b) Set GPU memory usage down to 192 or 128Mb (mine is currently 128Mb without problems)
(c) check the config settings below
(d) boot cleanly
(e) try again

Do you have these options in /boot/config.txt ?

# Force passthru of AC3 and DTS even when not reported in EDID
hdmi_force_edid_audio=1
# This is supposed to enable bitstreaming over HDMI ie. un altered data out
no_hdmi_resample=1
hdmi_stream_channels=1