סֶרֶט תִּעוּדִי
A film is a סֶרֶט
listen and repeat, invoking the Biblical Hebrew word for ribbon (film fed through a projector is a ribbon).
And while a (male) witness is an עֵד
listen and repeat, documentation – the written account of that which is witnessed – is תִּעוּד
listen and repeat.
For example:
אֲנִי מַעֲדִיף לִרְאוֹת סְרָטִים הוֹלִיווּדִיִּם וְלֹא סְרָטִים תִּעוּדִיִּם.
I prefer watching Hollywood films and not documentaries.
While סרט תיעודי is the proper Hebrew term, but you’re also likely to hear סֶרֶט דּוֹקוּמֶנְטָרִי
listen and repeat.