[haiku-bugs] [Haiku] #7285: BSoundPlayer sends buffers late, with ever-increasing latency

  • From: "Pete" <trac@xxxxxxxxxxxx>
  • Date: Sat, 26 Feb 2011 01:20:13 -0000

#7285: BSoundPlayer sends buffers late, with ever-increasing latency
-----------------------+-------------------------
 Reporter:  Pete       |        Owner:  nobody
     Type:  bug        |       Status:  new
 Priority:  normal     |    Milestone:  R1
Component:  - General  |      Version:  R1/alpha2
 Keywords:             |   Blocked By:
 Blocking:             |  Has a Patch:  0
 Platform:  All        |
-----------------------+-------------------------
 Once I got sound working reliably on my machine (see #7284) I was able to
 try apps like SqueekySynth and MidiPlayer, but I immediately ran into
 "Buffer Late" problems there.

 Often the app will start up OK, and I can drive it from a midifile or live
 input with marvellously low latency.  Shortly, however, the whole OS will
 get very sluggish, and sould usually quits altogether.  This seems to be
 usually triggered by mouse action, such as clicking a radio button.

 If I run 'top', I see the audio mixer hogging up to 80% of CPU.  Looking
 at 'tail -F /var/log/syslog', there are continuous "Buffer late" messages
 with ever-increasing lag.  (I've seen something like 28 million microsecs
 if I let it go long enough!)

 Once I terminate the app, things go back to normal,  but the same thing
 will happen the next time round.

 I can prevent it happening at all by using Cortex to change the run mode
 of the app to 'drop frames', rather than 'increase latency' but I imagine
 this isn't the correct solution.  MediaPlayer, which seems to have a
 slightly different buffer management scheme, never shows the problem,
 however hard I work the mouse buttons.

 (I'm still looking into this, but I wanted to get it into a ticket before
 any possible alpha deadline.)

-- 
Ticket URL: <http://dev.haiku-os.org/ticket/7285>
Haiku <http://dev.haiku-os.org>
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