Hey Mathieu,
Thanks for the tips much appreciated, I'm going to to work on something to extract sounds from video movements/colours basically. I've done this in Gem with pix_data & pdp with pdp_cog - trying out gridflow as I think there could be more ways of extracting values to explore
I dont think gridflow likes the mp4 suffix? the console displays [gf/io_generate 1012in] unknown suffix 'mp4' .Changing the suffix file manually from mp4 to .mov seems to resolve the issue though
Thanks again
On Wed, Aug 24, 2011 at 6:10 PM, Mathieu Bouchard matju@artengine.ca wrote:
On Tue, 23 Aug 2011, ALAN BROOKER wrote:
I hope to ask for some tips regarding obtaining values from a loaded image/movie file by using gridflow ? #store gets can get rgb values from a specified pixel position
You can pass multiple pixel positions at once to #store and it's much faster than getting pixels one by one. Those multiple pixel positions can in turn be organised in rows and columns so that you can make a new image by picking 100000 pixels in a single step, for example.
but any advice on getting the whole dimensions at once
What does that mean ?
(or any other techniques in getting gridflow to output values from a movie file such as movement, luminosity or anything)?
some kind of luminosity is what you get when you convert to greyscale. You may use [#rgb_to_greyscale].
Movement can be a lot of different things.
The easiest one is to subtract each frame with the previous one. Then you can know the change of luminosity from one image to the other, or the change of each channel. You do that using [t a a] and [# -] (plain diff) or [# sq-] (squared diff) or [# abs-] (absolute diff).
You can also identify regions or compute mean positions of things and then look at the position differences. Sometimes I did that using [#moment] and then [t a a] and [# -]. Note that often the same tools work on different kinds of data (pixel colours vs pixel positions). This is a feature of GridFlow which is not found in other image-processors of Pd (GEM/PDP/etc).
There are also algorithms to make a map of all translations (move) of pixels in the picture, but they have not incorporated in GridFlow.
...also is there support for mp4 in gridflow? the file format being the same as mov (I think?)
GF uses Quicktime.framework (by Apple) on OSX, and libquicktime (by H.W. & Plaum) on Linux and now also on OSX. Nearly all video file format support rests upon that.
GF also can run libmpeg3, but that's a MPEG1/MPEG2 decoder without plugins.
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