Re: Few sample rate conversion questions
Re: Few sample rate conversion questions
- Subject: Re: Few sample rate conversion questions
- From: William Stewart <email@hidden>
- Date: Fri, 23 Jan 2009 13:00:33 -0800
On Jan 22, 2009, at 11:56 PM, Mike Kluev wrote:
On Thu, 22 Jan 2009 14:03:30 -0800 William Stewart <email@hidden>
wrote:
On Jan 22, 2009, at 2:47 AM, Mike Kluev wrote:
I'll file feature request to make complexity controllable.
rdar://6520002
BTW, changing kAudioUnitProperty_SampleRateConverterComplexity
seems to do nothing with AUConverter (while the SetPropety call
returns noErr). Isn't that a bug?
It should be implemented with AUConverter , but it isn't with the
varispeed
Looks like it is just ignored in AUConverter. rdar://6519999
No - but what you do is a "latency pull" - you pull at least as
much latency samples through the AU providing correct input and
then throw out latency num samples of the output of the AU,
then you are good to go.
Yes, this works. When should I do this latency pull?
When you reset the audio unit - which you would typically do because
the input to the audio unit is discontinuous (for ex, you are seeking
to a different part of a file you are processing, you have muted a
track and you are unmuting it, etc...)
Sure I should do
it initially. I should probably do it after I change either source or
destination format, and maybe after unit reset. Correct? Is there
notification I could listen to know that I am supposed to do latency
pull?
There is also "tail", would you also recommend to skip tail frames?
These frames seem to look quite ok (not all zeroes, etc).
the auprocess basically does this:
pulls source + latency + tail samples through the AU (providing
silence for the end when you have to pull past the end of the source
material)
discard the first latency samples
include the tail samples in the output - thinks of this as the tail of
a delay or a reverb
Bill
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