[Alsaplayer-devel] Pitch shifting

[Andy Lo A Foe]

Austin, Jay,

Currently there's no pitch control. It could probably be implemented as 
a plugin.

In essence the speed is already controlled by skipping frames, but the 
frames that are skipped are still 'rendered'. I imagine some kind of 
optimization might be done to really skip over frames, but it would 
complicate things a bit. So no, not easy to add :)

Regards,
Andy

Jay Carlson wrote:
> This functionality wasn't present last time I checked.  I love the idea of
> unbound pitch / speed adjustments, but be forewarned it does use up a bit
> of CPU.
> 
> On a related note -- with mpeg playback (and ogg I suspect also), one can
> do simple unbound speed adjustments just by skipping frames.  Skip every
> other frame, and you have 2x (2/1) playback.  Skip every fifth frame, and
> you have 1.25x playback (5/4).  Likewise, one could go slower than 1x by
> doubling frames.  Double every fourth frame, and you have .8x playback
> (4/5).  Etc...
> 
> I personally would love to have this feature -- I'm imagining improved
> seek FWD / seek REV modes in my car .mp3 deck.
> 
> Andy, what do you think?  Would something like this be easy to add?
> 
> --Later,
> --Jay
> 
> 
> 
> 
>>Does libalsaplayer support shifting pitch without changing speed?
>>Conversely, can I change playback speed without changing pitch? I saw
>>some traffic about this in the list archives (but nothing conclusive),
>>and I don't see any support for this in control.h or other headers. My
>>knowledge of audio playback is such that I don't really even know if
>>this is reasonable, I just know it would be nice. Thanks.
>>
>>Austin Bingham
>>
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>>
>>
> 
> 
> 
> 
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-- 
Andy Lo-A-Foe
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