FFmpeg can also be compiled with an LGPL license so it can be linked in commercial products.
Also executing an external GPL library/binary from a commercial product (no direct linking) is not in direct contradiction with GPL terms (although it's a gray area where most companies would probably not want to go).
The last paragraph describe the gray area; i.e. if a proprietary program depends on- and combine a GPL program to perform its functionality it can be argued that the two parts are a combined work and hence the whole work must be licensed under the GPL.
Also executing an external GPL library/binary from a commercial product (no direct linking) is not in direct contradiction with GPL terms (although it's a gray area where most companies would probably not want to go).