CODEWITHSUNDEEP
actionscript-3audioarraysmp3
remi
remi

Reputation: 21

dynamically changing the playback speed of a sound in as3 without altering pitch

I'm making a game based on simple song creation, and I'm planning on having a feature where players can listen to the songs they've created with the game. the rhythm of the melody is controlled with a system of timers, but this will not work for the backing track presets I am planning on implementing, as each mp3 file in the backing tracks represents one bar instead of one note.

while it would be possible to use my timer system for playing the backing tracks, this would require several more audio files, much more coding and would push the project far behind schedule. therefore, i need to manipulate the playback speeds of the files I already have. I've commonly seen two examples of how to do this, here: http://2008.kelvinluck.com/2008/11/first-steps-with-flash-10-audio-programming/ and here: http://blog.andre-michelle.com/2009/pitch-mp3/

the problem with both of these is that they also alter the pitch as well. this is a problem for me, as I would very much like players to be able to alter the pitch and tempo of their songs separately. I think the code I need is similar to the examples above, but I'm having trouble understanding those since I haven't had much experience with bytearrays and such. I'd like to be able to understand the examples i included so that I can figure out what I need to do in order to get my game working the way it should, but help of any sort is appreciated. thank you =)

Upvotes: 1

Views: 671

Answers (2)

VC.One
VC.One

Reputation: 15881

You could also try :

http://iq12.com/old_blog/2009/08/25/real-time-pitch-shifting/

test : Online demo

Their online demo didn't load a track for me (deleted MP3?), so I put a recompiled SWF on my server just for testing. It loads this MP3 audio clip, if you wanna compare results to original sound.

It aims to preserve audio length (time scale) whilst adjusting pitch (deeper when slow or higher when faster). You could possibly combine this with Kelvin Luck's Second Steps.... Thereby having example codes for speed and pitch.

It was inspired by some C# code ported from this C code as found at (with concept explanation) :
http://blogs.zynaptiq.com/bernsee/pitch-shifting-using-the-ft/

Upvotes: 0

jauboux
jauboux

Reputation: 888

You can try https://github.com/also/soundtouch-as3 there is an early (alpha) demo at http://static.ryanberdeen.com/projects/soundtouch-as3/demo/player/stretch.swf quality is "acceptable" if you are using 1.0x-1.5x factor (less than 1.0 gives very artificial distortion)

Upvotes: 1

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