• 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
Re: ExtAudioFileRead accuracy..
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: ExtAudioFileRead accuracy..

  • Subject: Re: ExtAudioFileRead accuracy..
  • From: Paul Davis <email@hidden>
  • Date: Mon, 08 Feb 2016 20:47:04 -0500
use sample based measurements instead of wallclock time, and make sure that *you* get the math right.

the "inaccuracies" mentioned mostly concern compressed formats, not PCM data.



On Mon, Feb 8, 2016 at 8:32 PM, Alexander Bollbach <email@hidden> wrote:
Perhaps this is a pedantic point but I've noticed that ExtAudioFileRead does not read the amount of frames as requested.  Now I know it states that this may happen for technical reasons in the API documentation but I wonder if this inaccuracy is noticed in audio software.  For example, I created a 10 second Mono/32bitFloat PCM wav recording in audacity.  I create a buffer to read the information onto and than write it onto a new ExtAudioFile.  When opening this new file in audacity the audio data is 16ms shy of 10 seconds.  (like i said, pedantic..).  But I'm just curious if this is accepted as normal behavior and if there is a way to do precise editing using the ExtAudioFileRead/Write workflow. Is there a sample-perfect method using non-realtime Core Audio tools?  You can see the code I used to generate the new audiofile from the old one on github.

 _______________________________________________
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

 _______________________________________________
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
References: 
 >ExtAudioFileRead accuracy.. (From: Alexander Bollbach <email@hidden>)

  • Prev by Date: ExtAudioFileRead accuracy..
  • Next by Date: Hog mode, how to get an exclusive access to the sound card ?
  • Previous by thread: ExtAudioFileRead accuracy..
  • Next by thread: Hog mode, how to get an exclusive access to the sound card ?
  • Index(es):
    • Date
    • Thread