present participle問題

我不太肯定你的例句的準確性，因為第二句：

the film shown just now depicted ...
應該是
the film being shown just now depicted...

同樣是ing(現在進行的意思，只是being shown是表達套片是「被播放」的內容，而第一句the film showing...是表達套片本身的價值(worth seeing)所以用主動詞。

所以從這主動詞跟被動詞之間所要表達的情況決定那一種。當然用ing是包括現在仍在進行中的情況。所以兩者不會同時使用，要看內容中的處境和表述的目的。

An "ing" describe an action that is still continuing.
Example :
kicking, running, showing, dreaming, etc.

Yes, in most situation when something is continuing in motion we would naturally think it's a living thing that is doing the action, but in any language, we can always say the car is moving very fast. That does not means that the car is a living thing, it merely shows something (not necessary living things) is in a continuing state of motion.

A "ed" is usually added to a verb to show that an action was done in the past.
Example : kicked; depicted; kissed; dreamed, etc.
Like what I previously mentioned, movement is not necessary induced by living things, if :
Machines can move, trees can sway and even steel can be melted. All these non living things must at one point in time be, moving, swaying and melting before it can come to a stop and described as past tense.