[PD] video midi

[Christian Klippel]

hi guenter and the others ! .....

Am Freitag, 15. Juni 2001 21:35 schrieb guenter geiger:
> On Thu, 14 Jun 2001, Michael Droettboom wrote:
> > TECHNICAL DETAIL:
> > My overall architecture is to pass video data as if they were very large
> > blocks of audio data between objects.  My video_in_rgb object, for
> > instance, outputs three data streams, one for red, green and blue.
>
> All of this sounds great, I do have one question though.
> Why did you choose to implement your own data processing concept, instead
> of using the pix objects from gem ?
>
> Image data is inherently different from audio data, therefore the gain you
> have from being able to reuse the pd signal processing objects (which are
> optimized for audio calculations) doesn't seem to be worth it.
>
> Or put the other way, what was it that you didn't like about them
> GEM way ?
>
> Guenter

just my thoughts about it :

were currently implementing video into jmax, and i follow a similar way.
what i do is to split the 32 bit of a float into a union of 4x8 bit for rgba, called
pixel_t
these are "flowing around" like the normal audio data, but in a seperate chain, called vdsp.

the advantage is that you can do most of the calculations on a stream rather than on a whole picture.
imagine the following situation :

one video source, some calculations and maybe 4 effects (still on one video of course....)
most of the time nothing happens, but if you use whole images, then you have to do *all*
calculations on a whole image, spending lot of time *momentarily*...... if you stream them,
for example for additions etc, you only have to calc, lets say, 2048 pixels (together with a smaller number
of audio samples....)
this way you can "distribute" the computation power needed across small vectors of pixels.....and not
a whole image.....

if you need calculations that work only on a whole image (like distortions or so...) you can always store
one whole image in a buffer to apply calculations on it in the time.......

hope to cleared that a little ???
(if anyone has interrest, please contact.....)

greets,

chris

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