[linux-audio-user] Re:How can I time-stretch the sound like this (with SND & CLM)

Brad Fuller brad at sonaural.com
Thu May 25 01:51:47 EDT 2006


Paul wrote:
> Thanks for reply.
> I wanted to try by myself and I made last night a
> quick hack for extreme time stretching by using FFTs.
> I like the results very much.
> Here are some demos (the links will work only for few
> days):
> Original sound is this:
> http://zeus.integrasoft.ro/~nop/1stretch_paul_in1.ogg
> Stretched (over 60x) is this:
> http://zeus.integrasoft.ro/~nop/1stretch_paul_out1.ogg
>
> Please tell me your opinion about the stretched sound.
>
>
> The program is not complete (is just a quick hack
> written in about one hour), but if you are interested,
> I can put it somewhere on net (and make it usable and
> improve the quality :) ). 
>
> Paul
>   
FYI: This was on the dsp-music mailing list:

Hello!

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Music DSP mailing list, we'd like to draw the attention of its
subscribers to our new fast yet high-quality real-time timestretching
with transient processing and resampling libraries written 100% in
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plugin and licensing, visit our web site - http://www.dspteam.com/

Thanks for your time!
Audio DSP team


>
>   
>>> Hi.
>>> I found out a very interesting page and a webcast
>>> about the 9'th symphony of Beethoven stretched to 24
>>> hours here:
>>> http://www.park.nl/park_cms/public/index.php?thisarticle=118
>>> And on this page ( http://www.notam02.no/9/tech.htm
>>>       
> )
>   
>>> I found that for this was used CLM and SND.
>>> How can I do the same?
>>>       
>
>   
>> Its just a simple granulate processing with a tiny
>>     
> bit
>   
>> of reverb on top.
>> Halfly pseudo, it can look like this:
>>     
>
>   
>> (let* ((read0 (make-readin filename #:channel 0))
>>        (read1 (make-readin filename #:channel 1))
>>        (gr0 (make-granulate #:expansion 22.0
>>     
> #:length >0.15 #:hop 0.03))
>   
>>        (gr1 (make-granulate #:expansion 22.0
>>     
> #:length >0.15 #:hop 0.03)))
>   
>>   (do-X-number-of-times
>>    (output-to-file file-object (granulate gr0
>>     
> (lambda >() (readin read0)))
>   
>>                                (granulate gr1
>>     
> (lambda >() (readin read1))))))
>
>
>   
>> Very simple. You have to tune the length and hop
>>     
> sizes >though, plus volume 
>   
>> and stuff.
>> http://ccrma.stanford.edu/software/snd/snd/clm.html#granulate
>>     
>
>
>
>   
>>> It's possible to do this in
>>> batch mode?
>>>       
>
>   
>> Yes, the first first version of this stretch was
>> actually run in batch 
>> I didn't want to stay up all night generating all the
>> files. :-)
>>     
>
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>   


-- 
Brad Fuller
Sonaural Audio Studio
+1 (408) 799-6124
Hear us online www.Sonaural.com <http://www.sonaural.com/>
See me on O'Reilly <http://www.oreillynet.com/pub/au/2184>


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