Swat 2's movies use a codec that doesn't work with modern versions of Windows. These replacement movies have been re-encoded with Mpeg-4 codec and enlarged to 800x600 with AI software. Originally the movies were 320x240 in size.
Although Swat 2's videos are in .AVI format they are encoded with a codec (Indeo Video codec) that Microsoft no longer supports in newer operating systems. For the videos to run smoothly on Windows 8/10 it is recommended you download these replacement versions that are re-encoded with the Mpeg-4 codec. Overwrite the original movie files that are stored in the "Movies" folder of Swat 2.
I also used AI software to increase the movie size from 320x240 to 800x600 pixels.
Personally, I had to change the permission for a DirectX windows file ("dplayx.dll") to get to work. I had to change it from "READ" to "FULL CONTROL". Perhaps you won't need to do that.
Read about it here:
Swat3lastresort.info
Please note that the sound glitches that you hear are in the original movies also. Compression technology wasn't as advanced back in 1998.