I’ve continued to play around with this and there does seem to be a mt-daapd specific problem in addition to problems with alac files produced with some programs. I am now running svn-1498 and soundbridge 2.7beta 7. There is a program called Omni Encoder (see hydrogenaudio) which uses itunes to encode alac and aac into m4a files and to write the tags. The resulting file will stream to itunes or a soundbridge when served by itunes. When served by mt-daapd it works fine to itunes but croaks ( Write error: Broken pipe) with the soundbridge – perhaps an rsp problem.
For a sample file see: