RE: Increasing speed without increasing pitch
RE: Increasing speed without increasing pitch
- Subject: RE: Increasing speed without increasing pitch
- From: Waverly Edwards <email@hidden>
- Date: Fri, 18 Aug 2017 16:37:40 +0000
- Thread-topic: Increasing speed without increasing pitch
>> And it can go more than double-speed (I think the limits are 1/32x to 32x)
Wow. I constantly listen to spoken audio at 2-4x (my limit) so I tried
listening at rate from 5-32 using AVAudioUnitTimePitch . That is off the
charts fast.
This works perfectly under normal conditions. I couldn’t be more pleased.
However, my conditions aren’t the norm.
I am rendering offline by start playing the audio, immediately pausing the
engine, then pulling AudioUnitRender.
This has worked fantastically with all the effect so far but with
AVAudioUnitTimePitch, the audio render never occurs. I’m guessing because this
is a converter as you said. I’ll try some other converters to see what the
outcome.
Player -> TimePitch -> Mixer -> OutputNode
If I bypass TimePitch, while offline rendering everything works as expected.
I’ve been trying to determine if you can signal the unit to render offline.
So far I haven’t found a way to do this. Is there a way where I can make this
work while rendering offline (engine paused)?
Thank you for the insights. They were a massive help.
W.
From: Chris Adamson [mailto:email@hidden]
Sent: Friday, August 18, 2017 9:30 AM
To: Waverly Edwards <email@hidden>
Cc: CoreAudio <email@hidden>
Subject: Re: Increasing speed without increasing pitch
Just use AUNewTimePitch (or whatever it’s called) by itself. That’ll change
rate without changing pitch. And it can go more than double-speed (I think the
limits are 1/32x to 32x)
Note that this unit is of type format converter, not effect, because you of the
differing counts of input and output frames.
—Chris
On Aug 18, 2017, at 8:41 AM, Waverly Edwards
<email@hidden<mailto:email@hidden>> wrote:
Would someone provide some guidance on how you can take an audio file and speed
it up without changing the pitch.
I was working yesterday and I added AVAudioUnitVarispeed unit to my engine and
increased the speed by 2. It worked, however I found output to have the
chipmunk sound.
Would you use a AVAudioUnitTimePitch unit to lower the pitch to compensate or
is there a better way to achieve this outcome?
I would like to increase the speed by more than a rate of 2. Is there a reason
why I couldn’t daisy chain two AVAudioUnitVarispeed units together?
Lastly, is there a way to know how many audio frames were produced after the
effect completed. Since I have a change in time, the number of frames coming
in are not the same number going out.
Thank you,
W.
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