I’ve got some progress on Ace Combat resources research, have added code to unpack resources from base containers of AC4-6, besides Assault Horizon. Actual progress is shown here. Actually, it’s a low priority task I do when I’m stalled with others, so I’m not sure how soon Open Horizon will actually use resources from previous games.
Sound is a different story. I don’t want to mess with legal problems of CRI’s patented HCA proprietary codec until Open Horizon get any descent community around. Possibly, never. Upd: found an open source implementation under MIT license GARbro so I can port that to C++ and use in Horizon without messing with a suspicious source code from japanese boards.