I know the Roku has been "end of lifed" but I wonder if someone could help.
I recently upgraded my Roku to the 2.0.36 beta. Playing an MPEG transport stream (via TSReader)
works much better than it used to on high bitrate streams, in that I now experience no video problems.

Sound is a different issue however. The transport stream contains AC-3 sound, and I have the
Direct Digital Out setup option set on my Roku. With this combination, I get
no sound at all. If I change the Setup option to Stereo Downmix, I get sound,
but it has periodic dropouts (there are no continuity problems with the transport
stream and no error messages being issued from Cinema Six which is the playback
app being streamed to by TSReader).

I could swear that Direct Digital Out used to work on 1.5.18. I've looked through the
forum messages and can't see that anybody's reported that Direct Digital Out doesn't
work in the beta, but I'm wondering if it in fact does not. The only other possibility
I can think of is that the SPDIF output suddenly stopped working on my Roku -
if so, will Roku still repair these boxes or should I just try and find a new one?

Finally, is the sound dropout problem likely to be Cinema Six (I've seen old
warnings in its release notes about problems with AC-3) or is this a Roku issue when downmixing?
If it's Cinema Six, is there a more reliable app for the Roku that can accept realtime streaming
of MPEG transport streams via a network link?

Thanks for any help.

Try MPlay. Check it out in the the Third Party forum section. I play MPEG-2 TS files all the time, with no AC-3 problems, though admitedly I am using 2.0.34 firmware and not from realtime streaming files.

Thanks for the suggestion. I tried MPlay earlier and it gets video breakups (I'm
using NFS, not SMB) which is why I used Cinema Six (which gets no video
breakups doing HTTP streaming). MPlay also wouldn't play AC-3 either.