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[Csnd] PVS delay explanation?

Date2021-09-20 08:55
From"Jeanette C."
Subject[Csnd] PVS delay explanation?
Hey hey,
working with the fantastic PVS opcodes again, I experimentally worked out the 
delay to perfectly synchronise the original audio input with the PVS output. 
Using pvsanal and pvsynth respectively, with an FFT and window size of 1024 
and an overlap of 256, I arrived at )1024 + 512) samples delay.

Now why the 512? My intuition was to have the extra 256. Are the other 256 
independent of the analysis parameters or linked to either of the three 
parameters defining the FFT analysis?

I think I asked about this before, but somehow didn't fully appreciate the 
answer. Though that was probably some years ago. :)

Best wishes,

Jeanette

-- 
  * Website: http://juliencoder.de - for summer is a state of sound
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Date2021-09-20 10:11
FromVictor Lazzarini
SubjectRe: [Csnd] [EXTERNAL] [Csnd] PVS delay explanation?
Maybe the simplest way to think of this is:

1) it takes 1 hopsize to start getting the data in
2) it takes 1 fftsize to do the complete transform
3) it takes 1 hopsize to start getting the data out

So it comes out as 2 hopsizes + 1 framesize.

For a more detailed answer, you can read the code in pvsanal.c and work it out.
Maybe Richard, who wrote this, would be able to add to this.
========================
Prof. Victor Lazzarini
Maynooth University
Ireland

> On 20 Sep 2021, at 08:55, Jeanette C.  wrote:
> 
> *Warning*
> 
> This email originated from outside of Maynooth University's Mail System. Do not reply, click links or open attachments unless you recognise the sender and know the content is safe.
> 
> Hey hey,
> working with the fantastic PVS opcodes again, I experimentally worked out the
> delay to perfectly synchronise the original audio input with the PVS output.
> Using pvsanal and pvsynth respectively, with an FFT and window size of 1024
> and an overlap of 256, I arrived at )1024 + 512) samples delay.
> 
> Now why the 512? My intuition was to have the extra 256. Are the other 256
> independent of the analysis parameters or linked to either of the three
> parameters defining the FFT analysis?
> 
> I think I asked about this before, but somehow didn't fully appreciate the
> answer. Though that was probably some years ago. :)
> 
> Best wishes,
> 
> Jeanette
> 
> --
> * Website: https://eur02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fjuliencoder.de%2F&data=04%7C01%7CVictor.Lazzarini%40mu.ie%7C98a622aa24aa4378759d08d97c0bf53e%7C1454f5ccbb354685bbd98621fd8055c9%7C1%7C1%7C637677213077331330%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=jVHeF9FiiiribRHb7DDDWZw2P%2BdEXjHaJagS1o18iII%3D&reserved=0 - for summer is a state of sound
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> * GitHub: https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fjeanette-c&data=04%7C01%7CVictor.Lazzarini%40mu.ie%7C98a622aa24aa4378759d08d97c0bf53e%7C1454f5ccbb354685bbd98621fd8055c9%7C1%7C1%7C637677213077341325%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=V751fd6C1jl9Tuxpl8Fl5wNOPEAhAbJI5ziMMpHLICQ%3D&reserved=0
> 
> ... About some useless information,
> Supposed to fire my imagination <3
> (Britney Spears)
> 
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Date2021-09-20 10:32
From"Jeanette C."
SubjectRe: [Csnd] [EXTERNAL] [Csnd] PVS delay explanation?
Hi Victor,
thanks a lot. I think this is detailed enough for my purposes.

Best wishes,

Jeanette

-- 
  * Website: http://juliencoder.de - for summer is a state of sound
  * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g
  * Audiobombs: https://www.audiobombs.com/users/jeanette_c
  * GitHub: https://github.com/jeanette-c

... About some useless information,
Supposed to fire my imagination <3
(Britney Spears)

Csound mailing list
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Date2021-09-20 11:58
FromRichard Dobson
SubjectRe: [Csnd] [EXTERNAL] [Csnd] PVS delay explanation?
Nothing to add, I think that is exactly it.  I can't recall now if I 
ever did the comparison test (such a long time ago - all developed and 
tested on a Pentium II at 333MHz!), but using pvsaddsyn for the output 
should reveal the slightly shorter overall delay, as the additive 
resynthesis has no need for the overlap aspect.

Richard Dobson


On 20/09/2021 10:11, Victor Lazzarini wrote:
> Maybe the simplest way to think of this is:
> 
> 1) it takes 1 hopsize to start getting the data in
> 2) it takes 1 fftsize to do the complete transform
> 3) it takes 1 hopsize to start getting the data out
> 
> So it comes out as 2 hopsizes + 1 framesize.
> 
> For a more detailed answer, you can read the code in pvsanal.c and work it out.
> Maybe Richard, who wrote this, would be able to add to this.
> ========================
> Prof. Victor Lazzarini
> Maynooth University
> Ireland
> 
>> On 20 Sep 2021, at 08:55, Jeanette C.  wrote:
>>
...

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