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Re: Need to hire a software developer for a voice processing app!
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Re: Need to hire a software developer for a voice processing app!


  • Subject: Re: Need to hire a software developer for a voice processing app!
  • From: Wil Macaulay <email@hidden>
  • Date: Fri, 19 Feb 2010 14:09:27 -0500

I've had success in using the open-source soundstretch library to do
pitch shifting and
time stretching.  I haven't tried to do it in realtime, however.  I
would think that downsampling
to 16000 kHz mono you could get close.

(our app is almost ready to go - http://iliftapp.com)

wil


On Fri, Feb 19, 2010 at 1:43 PM, William Stewart <email@hidden> wrote:
>
> On Feb 19, 2010, at 10:38 AM, Thomas David Kehoe wrote:
>
>> On 2/19/10 12:39 AM, "tahome izwah" <email@hidden> wrote:
>>
>>> Last time I checked AUPitch wasn't supported on the phone. There are
>>> other alternatives, even free ones such as DIRAC which is also
>>> available for the iPhone:
>>> http://www.dspdimension.com/technology-licensing/dirac2-iphone/
>>>
>>> Also, the DSP Dimension have done DSP development for our studios in
>>> the past so you might want to contact them. Another company that comes
>>> to mind is Art & Logic (http://www.artandlogic.com)
>>
>> DSP Dimension's website says:
>>
>> "DIRAC2 brings the power of DIRAC to your iPhone projects. Highly
>> optimimzed
>> for the ARM6 and 7 processors this library allows affordable studio
>> quality
>> time stretching in any of your apps – without much effort. DIRAC2 on the
>> iPhone has been specially designed and optimized to run near-realtime
>> (preview mode) on the iPhone. Higher quality modes are also available."
>>
>> The DIRAC PRO version has unlimited sample rates, so I'm sure if the
>> sampling is reduced it could run in real-time. My company's speech aids
>> use
>> a Yamaha pitch-shifting chip with 448 kbits per second (14-bit, 32 kHz)
>> sampling. In comparison CD-quality is 705 kbits per second (16-bit, 44.1
>> kHz). I can clearly hear a difference when processing my voice, but 448
>> kbits is perfectly acceptable.
>>
>> BTW, is 449 kbits twice as much data as 448 kbits?
>
> no- its not binary. it is 1kbit more.
>
>> So 705 kbits is
>> 257-to-the-power-of-two times more data, or 66,049 times more data?
>
> no - its not binary.
>
>>
>> DSP Dimension's website also has an article about pitch shifting, "Pitch
>> Shifting Using The Fourier Transform":
>>
>> http://www.dspdimension.com/admin/pitch-shifting-using-the-ft/
>>
>> --
>> Thomas David Kehoe
>> Casa Futura Technologies
>> http://www.casafuturatech.com
>>
>>
>>
>>>
>>> HTH
>>> --th
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References: 
 >Re: Need to hire a software developer for a voice processing app! (From: Thomas David Kehoe <email@hidden>)
 >Re: Need to hire a software developer for a voice processing app! (From: William Stewart <email@hidden>)

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