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

  • From: "bonefish" <trac@xxxxxxxxxxxx>
  • Date: Thu, 12 May 2011 19:20:21 -0000

#7285: BSoundPlayer sends buffers late, with ever-increasing latency
   Reporter:  Pete            |      Owner:  axeld
       Type:  bug             |     Status:  new
   Priority:  normal          |  Milestone:  R1
  Component:  Kits/Media Kit  |    Version:  R1/alpha2
 Resolution:                  |   Keywords:
 Blocked By:                  |   Blocking:
Has a Patch:  1               |   Platform:  All

Comment (by bonefish):

 Replying to [comment:21 Pete]:
 > Replying to [comment:20 bonefish]:
 > > No, performance time is always in microseconds.
 > >
 > Are youo sure (that that's what Be intended)?  The BeBook is either
 pretty explicit or pretty confused (in the BTimeSource chapter):
 > ...[[BR]]
 > They make a clear distinction there between microseconds and "time

 I'm too lazy to search whether "time units" is explained somewhere. I'd
 simply guess they wanted to point out that 1 performance time unit does
 not exactly equal 1 real time microsecond (due to a possible drift).

 At any event a performance time unit must denote some fixed length of
 time. It cannot be some format dependent value (e.g. 1/44100s) as you
 suggested, since the format may be different at the beginning and the end
 of the media node chain (e.g. 44.1kHz CD player and 96kHz sound card), but
 still both ends must use the same time source. Theoretically some behind-
 the-scenes conversion could take place, but that would just complicate
 things without any benefit I see. Also, a good indicator is that
 `bigtime_t` is used to store performance time values, which is quite
 consistently only used for microsecond values.

Ticket URL: <http://dev.haiku-os.org/ticket/7285#comment:22>
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