[Xerte] Sound rate?

[Mark Tomlinson, AC&S Ltd]

Also found this on an Adobe flash player engineers blog relating to video,
but there is a quote on MP3 audio also.:

 

Will the Flash Player be limited to 11Khz, 22Khz and 44.1Khz sampling rates
like for MP3? No, we support all sampling rates from 8Khz to 96Khz. I
implemented a 32 tap  <http://en.wikipedia.org/wiki/Kaiser_window> Kaiser
Bessel based FIR filter which resamples the sound to 44.1Khz, retaining high
quality. The most common sample rate combinations have a hard coded number
of phases. In case of a 48000 to 44100 Hz conversion the filter has 147
phases f.ex. Even better: Flash Player Update 3 Beta 2 now can play back any
MP3 sampling rate leveraging the same code I implemented for AAC. No more
chipmunks. Ever. Err, this is actually kind of major as I have seen
complaints about this bug for years :-) I fixed this problem in the AS3
Sound class, though it was using very low quality resampling. This change I
made this time will fix it even for AS2 and sound in FLV files while
retaining excellent quality.

 

This is from August 2007, so I would have expected this to have made it into
the latest version of the flash player by now??

 

 

 

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From: xerte-bounces at lists.nottingham.ac.uk
[mailto:xerte-bounces at lists.nottingham.ac.uk] On Behalf Of Dave Burnett
Sent: 31 January 2009 13:27
To: Xerte list
Subject: RE: [Xerte] Sound rate?

 


For the archives, I tracked the problem to the encoder settings I was using
to convert other sound formats to mp3.

The default encoder settings had a bitrate of 128 Kbps. This appears to be
handled by WMP no problem, but gives the Alvin the Chipmunk effect within
Xerte.

Boosting the encoder bitrate to 190 Kbps minimum seems to have solved it.

Dave 
 



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Subject: RE: [Xerte] Sound rate?
Date: Fri, 30 Jan 2009 19:56:36 +0000
From: Patrick.Lockley at nottingham.ac.uk
To: xerte at lists.nottingham.ac.uk

>From experience, its something to do with the id tag in the mp3. I think,
but its been a while since I tried.

 

  _____  

From: xerte-bounces at lists.nottingham.ac.uk on behalf of Dave Burnett
Sent: Fri 30/01/2009 19:21
To: Xerte list
Subject: [Xerte] Sound rate?

I have a 50K external .mp3 that plays fine in WMP.

If I hook it to a sound icon, the rate seems to speed up to double or
triple.
??

Dave










 

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