PCSX2 emulator developer explains GPL code-related info regarding AetherSX2
The new AetherSX2 emulator made waves across the emulation scene when it was quietly announced to the world. It promised PlayStation 2 emulation on Android, and with good performance to boot, which left many wondering how this emulator came to be, especially after the release of DamonPS2, which used another PS2 emulator's code--PCSX2--without complying with GPL licensing, and even selling the software for profit. One of the developers from the PCSX2 team decided to look into the matter and release an explanation that clarifies some details about the mysterious new AetherSX2 emulator.
As it stands, PCSX2 is open source and complies with GPLv3, with three instances of code that are part of the software: debugger code from another emulator--PPSSPP, the FreeType library, and libmpeg2. With AetherSX2 presumably using the code from PCSX2, it would need to remove those GPL bits of code in order to not have any issues upon release. Fortunately, the two dev teams got in contact, and it appears that the remaining code won't be a problem by the time AetherSX2 is made publicly available. The FreeType OSD and PPSSPP debugger aren't used, as AetherSX2 has its own OSD and does not make use of any of the debugger code. Meanwhile, while it does use libmpeg2, the developer has stated that it'll be simply replaced by FFmpeg, meaning the entire project will be LGPL and in the clear.
The existence of these 3rd party GPL parts means that PCSX2 as a combined works needs to comply to the GPLv3 license but our source code that we own remains LGPL. By distributing the code when requested we comply with the GPLv3 license. See the GNU FAQ here and here. If these mentioned libraries are removed, the entire project would become purely LGPL licensed.
These concerns of course extended out to this new emulator, and we had to reach out about it to Tahlreth. After a good discussion with him about these issues, we have been assured that it will no longer be a problem by the time the emulator releases. Right now the only piece of GPL code they need to contend with is libmpeg2, which can be replaced with FFmpeg, which is under the LGPL license; this is something we planned on doing in the future, since libmpeg2 is over a decade old. As for the aforementioned debugger and Freetype code, they no longer exist. Aether has its own OSD and no debugger, meaning the emulator will be entirely LGPL.