PDA

View Full Version : Re: Audio dropouts during "Search Music" - Possible toincrease buffering?



Mark Lanctot
2006-02-10, 22:32
nico:

Sounds like some good detective work. Would you mind
updating the wiki to reflect this? Just so that
others don't get confused.

Thanks.

--- nico <nico.231nlb (AT) no-mx (DOT) forums.slimdevices.com>
wrote:

>
> Cool. I did try the 8 megabit == 1 megabyte calc
> before and also got the
> 6-8 seconds theoretical value you quoted. But
> *empirically*, the results
> seems to show that < 2s is buffered, which agrees
> more with the
> implication that only about 256 Kbytes are being
> buffered.
>
> On my platform (UNIX) I can suspend and resume the
> slimserver.pl
> process at will to conduct tests. If playback is
> proceding normally,
> watching the buffer fullness display on the SB1 &
> the output from
> d_slimproto, I see the buffer is 99-100% ("228868" -
> whatever units of
> measure that is in). Then I suspend the slimserver
> process. In <2s the
> fullness display drops to 0% and the audio stops.
> This isn't close to
> the 6-8 seconds you'd expect. 2s @ 150Kbytes/sec ==
> approx 300Kbytes,
> which is close to the number displayed (228868).
>
> Digging around a bit further I found this:
>
> http://wiki.slimdevices.com/index.cgi?SB1Hardware
>
> This account of the SB1 hardware claims a "2Mb
> high-speed buffer". This
> may be more like the truth. 2Mb = 256Kb (262,144
> bytes exactly) which
> corresponds to exactly 1.49s of 44.1KHz/16-bit
> stereo PCM audio.
>
> Thus the mystery is finally solved. The number
> displayed in d_proto's
> fullness output does appear to be bytes. Working
> backwards from
> "228,868 == 98%", the implied buffer size is around
> 233,539 bytes. This
> is in line with the 2Mb buffer spec. It would appear
> that approx 28Kb of
> buffer memory is used for other things.
>
> Thanks to all who contributed to this thread.
>
>
> --
> nico
>
------------------------------------------------------------------------
> nico's Profile:
> http://forums.slimdevices.com/member.php?userid=672
> View this thread:
> http://forums.slimdevices.com/showthread.php?t=20863
>
>