Forum

Motion tracking

vvvv beta general
#1

hello everybody,

is it possible to realize a kind of motion tracking in combination with
a webcam. i was think about getting a motion var (like flash webcam.activity) on
a scale from 0-100 and to relate this value to a movie playback behaviour - like playing fwd on activity values from 50-100 with a raising speed and playing backwards on activity values from 0 -50…

playing backward seem like i read to be a problem?
has anyone some suggestions who i could realize this…

best wishes & thanks a lot

#2

hallo,

if you’re into programming, you could write a freeframe filter doing motion detection. see description and how to on this tiki here: freeframe. use the opencv library, a computer vision library providing algorithms for most common computer vision tasks.

if yoou don’t want to get stressed hacking dlls and stuff like that, try eyesweb maybe. i could guess, they have something like what you need. you should find some information about vvvv and eyesweb somewhere on this tiki, since a few people have done projects using eyesweb and vvvv. so there should be some knowledge on this somewhere.

good luck, michel.

#3

ao.

detecting activity in different areas of a video can easily be accomplished with the Trautner (FreeFrame DShow9) node. see the according helppatch.

playing back a movie backwards could be tricky. you’ll need to find a codec that will let itself playback backwards. good lukc.

#4

One codec that works well for playing backwards is Indeo set to keyframe every frame (I’ve only tried this in visualJockey). Probably there are other codecs that would work as well (maybe MJPEG?)

#5

i have done that with indeo codec, as mang sez, just put keyframe on every frame…

#6

Playing video backwards: Any non-delta compressing codec should do the trick if you select the frames individually (from an LFO). Like: Uncompressed (usual trick is to reduce resolution to 320x240 and have no compression artifacts in return), or HuffYUV (512x512 easily), or any MJPEG Codec (we have been happy using the commercially-available PICVideo MJPEG) or - also rather good - DV AVI as captured from your firewire cam.
Indeo IMHO is a rather bad performer both spatially and temporally.

The MoCap you describe is well possible with trautner, as joreg said, only for more complex video processing, eyesweb is the way to go. See howto use vvvv with eyesweb.

max

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