[Clam-devel] Re: Zero crossings and so ons...

[Han, Yushen]

Hi, Greg

1. "Do you think you could identify zero crossings on the fly after
you've already resynthesized your two new frames?"
This is an interesting question and my answer is no. I can't do this
unless I have the access to the samples in a frame. So far all I did
is in the frame level. Is there anyway for me to operate on sample
level?

If I could do so, the zero crossings after re-synthesis will have
little to do with the zero crossings in the original samples.

2. The jitter is associated with the frame that has been transformed
by SMS when the frequency between two consecutive frames changes a
lot. I know if there is only one SDIF file, this definitely will
occur.

As you designed, if there are more than 1 SDIF file, the program
should have catched more than 1 reader and will choose the most
suitable reader ( SDIF file ) on the fly.
I need to figure out if the jitter is related to the switching SDIF
file readers as well...

3. It is good to know that the sound problem is not due to the triangle window.
So I can focus on the transition part.

4. For the "mock-up", do you mean something like a blue print of the
interface that is not really sfunctional?
If so, I can just use XCODE Interface Builder...


Best regards,
Han, Yushen



On Thu, Jul 3, 2008 at 6:32 AM, Greg Kellum <greg.kellum at gmail.com> wrote:
> Hi Yushen,
>
> Here's a response to your earlier mail...
>
> I could imagine that it would be difficult to preserve the loop points
> you found after an analysis / resynthesis.  Do you think you could
> identify zero crossings on the fly after you've already resynthesized
> your two new frames?  When you wrap back around in a loop maybe you
> could just offset the start point of the loop by enough samples to
> make sure that the phases of the end and the start of the loop are
> aligned...
>
> You had also asked about the triangular envelope...  Well, a
> triangular envelope is already being using in SMS for overlapping
> frames.  This happens in the class OverlapAndAdd (I think).  And it
> doesn't introduce any artifacts...  Kontakt also uses triangular
> envelopes in looping...  Um...  Is there another alternative to using
> a triangular envelope?  Well, I suppose you could use no envelope at
> all as you mentioned...
>
> You also mentioned problems with jitter.  Is this the same question
> that you wrote about in your more recent email?  I wasn't sure that I
> understood the problem.  But I'm downloading your tar file, and
> hopefully, there are some sound files in there where I can hear the
> jitter...  Maybe that will help...
>
> With regards to the user interface, it would be cool if you had enough
> time to make a stand-alone application with its own GUI.  They're
> already using Qt for CLAM.  So, I suppose it would be best if you were
> to use Qt as well, and I think portmidi is already built into clam.
> So, I suppose you could use either that or OSC for input.  I suppose
> if you have some time to make some mock-ups of the user interface then
> we could make comments about them...  I'm working on OS-X as well, and
> I usually use OmniGraffle to make mock-ups and then save them as
> pdfs...
>
> Best wishes,
> Greg
>