Henry Wilkes authored Jan 13, 2020 and Thibault Saunier committed Jul 30, 2020

Stop setting the track 'caps' property. The previous code could
overwrite a users own setting of the caps for video and audio caps.
Moreover, the 'caps' property is listed as construct only, and users
will likely expect it to stay the same after a track has been added to a
timeline.

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