[CinCV TNG] LV2 plugins: sluggish display and other problems

Good Guy good1.2guy at gmail.com
Wed Jun 20 18:02:48 CEST 2018


In this case, the main issue is that the bfrsz is causing an animation
granularity.
This is both good and bad in the case of the analyzer.  The principle
function is
the FFT (fast Fourier transform).  The buffer size determines the precision
of
the measurement, but the presentation speed is only as fast as it arrives.
The
actual problem is that the analyzer does not seem to oversample (or
subsample)
the buffers.  eg:
bfr= ((prev2)(prev1)(prev)(now)), as opposed to bfr= (now)  4 times as much,
but sort of interpolated in the frequency domain.  This is a common
strategy in
audio FFT buffering (see echocancel).

Currently, the lv2ui refresh rate is set to a max of 30 frames per sec, but
if the
buffers are 16384 then the buffers arrive at 16394/48000 (every 1/4 sec).
This
makes the update seem jumpy.  I will add a mod to up the refresh rate to
2 times the buffer arrive rate (with a minimum of 30) so you have a way to
go
up to 48000/1024 (48 fps vs 30 fps).

This is an artifact of the plugin processing.  It can combine or bust up
buffers
to oversample/subsample so that the graphics appear continuous.   I don't
think that it would be a good idea to bust up cinelerra audio buffers just
to
make the presentation graphics pretty.

demo of the effect of playback buffer size:
https://www.datafilehost.com/d/da722a2c

gg


On Wed, Jun 20, 2018 at 9:04 AM Olaf <cinmail at womentie.de> wrote:

> Am 20.06.2018 schrieb Good Guy:
>
> > I am not exactly sure which sluggish you may mean...
>
> A picture says more than a thousand words.
> - https://streamable.com/f7c3k
> The upper analyzer runs natively (via Jack), the lower one comes from Cin5.
>
> Many thanks for the impressive explanation from a developmental point of
> view. But I'll be frank with you, I'm no help at all.
>
> _______________________________________________
> Cinelerra mailing list
> Cinelerra at lists.cinelerra-cv.org
> http://lists.cinelerra-cv.org/cgi-bin/mailman/listinfo/cinelerra
>
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