For the trial edition of FFVCL, there are not any *.dcu files distributed individually. All the *.dcu files were built in the packages – BPL/DCP files. So you have to configurate your project to build with runtime packages as below.
In Delphi IDE -> Main Menu -> Project -> Options -> Packages -> Runtime Packages -> Check “Build with runtime packages” -> Add “FFmpeg_Dx” (you’d better clear other packages.)
To run your application with the trial edition FFVCL, you need to place FFmpeg_Dx.bpl into the same folder of your application(exe), or add the path of FFmpeg_Dx.bpl into your PATH environment variable of Windows.