Here is a URL that will take you to the Part 74 rules and regs regarding wireless microphone frequencies in UHF.
Please note that movie producers are defined in this as: "Motion picture producer. Motion picture producer refers to a person or organization engaged in the production or filming of motion pictures."
Part 74 then lists all the frequencies that auxiliary low powered stations can use , some of which are 470 to 806 and 944 to 952 MHz. Then movie producers are listed as one of the groups that can use low power auxiliary stations (wireless mics are one type station). All is well, right?
Then here is the gotcha:
"(d) Cable television operations, motion picture and television program producers may be authorized to operate low power auxiliary stations only in the bands allocated for TV broadcasting."
TV broadcasting, however, is the UHF range of 470 to 806 MHz, some of which is gone or disappearing. Specifically, 944-952 MHz is not TV broadcast. Therefore, 944-952 is licensable only to broadcast entities but not to the groups in (d) above, including movie producers.
Frankly, the rules are confusing and seem to say that 944-952 is usable by movie production but then that section quoted above takes it away.
Hope this makes the fog more palpable.