• Open Menu Close Menu
  • Apple
  • Shopping Bag
  • Apple
  • Mac
  • iPad
  • iPhone
  • Watch
  • TV
  • Music
  • Support
  • Search apple.com
  • Shopping Bag

Lists

Open Menu Close Menu
  • Terms and Conditions
  • Lists hosted on this site
  • Email the Postmaster
  • Tips for posting to public mailing lists
Variable-Variable Speed Playback
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Variable-Variable Speed Playback


  • Subject: Variable-Variable Speed Playback
  • From: Wayne Anderson <email@hidden>
  • Date: Mon, 11 Jul 2005 17:33:44 -0600

I need to vary the playback speed of a sound sample where the speed is controlled by a mathematical curve.
That is, the instantaneous playback speed is proportional to the instantaneous slope of the curve.
Assuming the slope is always positive, the varispeed audio unit seems like a good choice for this.
To use it, I plan to use an algorithm that maps a set of straight line segments to the curve.
The slope of each segment is proportional to one of the available discrete steps on the varispeed unit.


My questions are as follows:

1) What are the limitations, if any, on real time programatic setting of the speed while playing?
2) what are the actual discrete settings that the unit can accept?


The default interface implies that the minimum unit is Cents, Is this really the internal resolution?
Are there preferred increments or "magic numbers" that improve performance and/or output quality?


3) what are the differences between the highest and lowest quality settings?

What about the more general problem of curves that have slopes that can go both positive and negative.
That is, the playback speed would vary and possibly reverse with some varying speed.


Any information or thoughts on this problem would be greatly appreciated.


Wayne


__________________________________ Wayne Anderson Red Rock Software, Inc. _______________________________________________ Do not post admin requests to the list. They will be ignored. Coreaudio-api mailing list (email@hidden) Help/Unsubscribe/Update your Subscription: This email sent to email@hidden
  • Follow-Ups:
    • Re: Variable-Variable Speed Playback
      • From: Chris Rogers <email@hidden>
  • Prev by Date: Re: Metering response time
  • Next by Date: Finding the attached Device Endpoint for External Devices
  • Previous by thread: Re: Metering response time
  • Next by thread: Re: Variable-Variable Speed Playback
  • Index(es):
    • Date
    • Thread