Can someone please review my new Jack output layer and either commit
or offer feedback please

Seconding that. A month or two ago I checked out the above Hg url, but
it still stuttered. I'd love to see flac working properly through jack.

Can you please confirm that it's fixed with my updated driver?  if not can you please send me an example file which doesn't work?

My guess is that it was due to the old code blocking until enough space became available to write the whole chunk - if xine were feeding in the chunks larger than the soundcard buffers then it would block until the buffers were empty...

Ed W