[PD] obscuring voices while maintaining intelligibility

[Lorenzo Sutton]

On 09/22/2011 07:15 PM, Hans-Christoph Steiner wrote:
>
> On Sep 22, 2011, at 5:29 AM, Lorenzo Sutton wrote:
>
>> On 21/09/2011 22:44, Hans-Christoph Steiner wrote:
>>>
>>> I'm trying to come up with a simple voice scrambling technique that
>>> leaves voices understandable, but makes them unrecognizable. A key part
>>> of this is to make it very hard to reverse the scrambling to make the
>>> voice more recognizable.
>>
>> Ineresting. Also these possible approaches come to mind:
>>
>> - Trivial, probably off-topic: use a TTS. Only thing that is
>> recognisable is the software which produced it.
>> - Use some sort of granulation with random pitch-shifting. Not sure
>> how easily reversible this would be.
>>
>> A fun thing might be mix the two: that is start from a TTS and then
>> feed it into the granular... Here a silly example made with Festival
>> TTS and granulation in Granita (the first sentence is the 'original'
>> produced by Fesival) with different settings and degrees of
>> recognisability:
>>
>> http://lorenzosu.altervista.org/temp/dump/voice01.ogg
>
> That sound has a lot of nice examples, can you share the patch for that?

I was using my own Granita [1] which also has a "play" gadget.

> text-to-speech is interesting, but that requires speech-to-text, which
> is error prone and not something you can easily run in realtime on a
> phone while processing video. Granular can be heavy too,

True, I hadn't thought you were on resources budget, but indeed you had 
mentioned CPU usage, Granita for ex.. is quite hungry, although you can 
lower it's demands (see README). I don't think it would run on a phone.. 
never tried though.

Lorenzo.

[1] http://lorenzosu.altervista.org/pd/granita/

  but I suppose I
> could try a lightweight version.
>
> .hc
>
>
>>
>> Lorenzo
>>
>>>
>>> I'm currently thinking that a ring modulator would work well for this,
>>> and it uses minimal CPU. Can anyone think of a way to reverse the ring
>>> modulation? I attached my quick sketch.
>>>
>>> .hc
>>>
>>>
>>>
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