[@Brad Rogers] To redistribute the binaries with or as part of your program they MUST compile the binaries with a compatible set of license switches, as their product is closed source for there to be a compatible license they MUST compile using the enable-lgpl switch not the enable-gpl switch. It is irrelevant how they execute the FFMPEG binaries whether by command line or by DLL API calls it is distribution of the GPLv3 code in a closed source product or in even worse cases the distribution of non-distributable editions with enable-non-free switch which some developers do breaking international laws.
VLC is open source so can include FFMPEG binaries under GPL or LGPLv3 or later license options. Handbrake is ALSO Open source and so has GPL and LGPL licensing of any FFMPEG code being included which may be static compiled into handbrakes binaries but are certainly not present as stand alone binaries distributed with the program.
Handbrake and VLC also both include a copy of “copying” file or “copying.txt” file. Are you claiming that grabtube is also Opensource published with a GPLv3 compatible license and I have made an error in deducing that it was a closed source product?
Please don’t assume you know the terms of GPL license because you’ve read something somewhere, read the license itself first and comprehend it… if it was OK to include GPL code in a closed source product there would be no need for LGPL!