<br>Hi Eric.<br><br><br><br><div class="gmail_quote">On Tue, Feb 28, 2012 at 7:57 AM, Erik de Castro Lopo <span dir="ltr"><<a href="mailto:mle%2Bla@mega-nerd.com" target="_blank">mle+la@mega-nerd.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi Klaus,<br>
<br>
I'm not really sure where to start with this one.<br>
<div><br>
Klaus Schulz wrote:<br>
<br>
> My first post over here.<br>
><br>
> While working on a music server optimzation (which ususally goes hand in<br>
> hand with running pretty low buffers on realtime<br>
> streams)<br>
><br>
> I figured that certain HiRez flacs were causing XRUNS/hickups on my Linux<br>
> server platform.<br>
<br>
</div>What is a HiRez flac? How does it differ from a regular flac?<br>
<div><br></div></blockquote><div><br><br>HireRez flac > 16/48 e.g. 24/96 flacs.<br><br>Decoding demands are somewhat different from 44/16 especially if a high compression level on 24/96 is used and the file gets decoded in realtime.<br>
<br>The subject is probably about realtime decoding efficiency. It's probably not that easy to trace this down.<br><br><br>The flac application is used as a realtime decoder to stdout (pipe) in a typical Squeezebox server setup.<br>
<br>As I said. People reporting ( me to) running into "hickups" when streaming e.g. level 8 24/96 hirez-flacs. Getting them down to compression level 0 solved some issues.<br>It happened always on the some tracks. <br>
<br>I'm not sure what happens. Perhaps a buffer underrun on the receiving end of flacs stdout stream under certain conditions. <br><br><br>One idea that came up:<br><br>When reading the flac instruction page I do have the feeling that those instructions and aliases are still made for <=16/48.<br>
<br>The first thing that hit my eyes was the thing about different blocksizes to be used for material >=48khz.<br><br> The whole world is using those standard compression level aliases which wouldn't be in line with the blocksize recommendations for HiRez. <br>
<br>I'm wondering what the most efficient ( related to decoding performance and NOT compression factor ) parametrization for a 24/96 file would be.<br><br>I'd like to give that a try. <br><br><br></div><blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div>
> The interesting thing is to run into XRUNS even though the stream gets<br>
> send to a Squeezebox Touch which got a 20s buffer on its receiving end.<br>
<br>
</div>XRUNS are a kernel/music player thing and not really anything to do<br>
with the FLAC library.<br></blockquote><div><br><br>I know. At least not directly. It's the pipe which breaks. The flac library ( or better the flac(.exe) applications could have some inefficiencies built in that show up on highly <br>
demanding HireZ realtime decoding.<br> </div><blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<br>
In order to better understand this issue, you need to separate the decoding<br>
from the playback. Do you have two files, one which rarely/never displays<br>
the problem and one which usually/always displays the problem? Are you<br>
able to post those files to a public website where I can retrieve them<br>
and test them?<br>
<span><font color="#888888"><br></font></span></blockquote><div><br>I think I'm not allowed to post them. Copyright.<br><br>Is there a way to debug certain issues?<br> <br>Klaus<br><br></div><blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<span><font color="#888888">
Erik<br>
--<br>
----------------------------------------------------------------------<br>
Erik de Castro Lopo<br>
<a href="http://www.mega-nerd.com/" target="_blank">http://www.mega-nerd.com/</a><br>
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