7 ‐ Chaining

For complete documentation see Working with Results on the docs site.

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Analyses often come in sequences: trim the video, extract the motion, draw the motiongram. Because every method returns the object it produced, a sequence can be written as one line, each call feeding the next—like a sentence rather than a list of errands.

Every analysis method returns its result object (MgVideo, MgImage, or MgFigure), so calls can be chained directly:

import musicalgestures as mg

mv = mg.MgVideo('/path/to/video.avi', skip=4, crop='auto')

mv.motion().show()
mv.motionvideo().history().show()
mv.motionvideo().blend(component_mode='average').show()

mg.MgVideo('/path/to/video.avi', skip=4, crop='auto').motion().history().average().show()

The basic non-chained workflow is equivalent and sometimes clearer:

mv = mg.MgVideo('/path/to/video.avi', starttime=5, endtime=15, skip=3)
mv.motion()
mv.history()
mv.show(key='motion')
mv.show(key='history')