Hi folks. My first post over here.
While working on a music server optimzation (which ususally goes hand in hand with running pretty low buffers on realtime streams) I figured that certain HiRez flacs were causing XRUNS/hickups on my Linux server platform. The interesting thing is to run into XRUNS even though the stream gets send to a Squeezebox Touch which got a 20s buffer on its receiving end. However. Even a potentially short break of that flac decoding stream seems to cause a problem further downstream. What to do!?!? I did this and that. Nothing worked. I tested the integrity of those files. I also run them as .wav. That turned out to be OK. I'm running flac 1.2.1 on a 64bit Ubuntu server btw.. The interesting thing is that not all flacs behave the same. Some are running smooth. Others skip. Which is reproduceable. Than I found a thread discussion in the Squeezebox Server area about this very same subject. The discussed solution solution was: RE-ENCODING to alias 0. Higher compression level seemed to cause those hickups. Ok. It's not just me. I wrote a batch script and re-encoded all those flacs to alias level 0. However. The problem didn't go away in my (rather special) case. If I'm running the offline decoded .wav of those 24/96 files I do not have any problems. Hmmh. Next. I then looked up the flac formatting guide. I figured that the encoding options used by the majority of applications are just the basic aliases 0-8. What struck me was that the flac formatting guide recommends higher (whatever) blocksizes in case of >48khz HiRez files and also a residiual partition order of 2,2. Since I do not have a lot of background about the internals of the decoder. I can't make much sense out of the advanced features of the formating guide. I'd really appreciate if somebody could tell me what best options to choose for encoding HiRez flacs. My goal would be to achieve the most efficient realtime stream decoding. Probably I'd have to play with blocksize and -r. Another comment: I'm wondering if the flac formatting guide shouldn't be updated with information related to HiRes data. If the blocksize should be higher for Hirez as described in the guide there perhaps should be new aliases for Hirez material. I guess the majority out there is still using use those standard aliases which would apply for samplerates <= 48khz only. Thx a lot. Cheers Klaus
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