ffmpg support the largest number of file formats, so that can be used, and the features you are looking for can be developed.
most of the features you have listed in given description,,
now can we talk more in requirement and other details?
ping me when you are online and free to chat.
About Me:
I am expertise in Mobile Application development and have more than 8 year of experience,
Worked in :- Android Native,Kotlin, Swift, IONIC Framework, React Native,Firebase.
Mobile App :- Cricawaaz, 2degrees,Hapcard, MyCanvas, Route Finder, Studydunes Helping Hand,My Music,My Movies,GRUPIO,Pocket Toons,MagiMoji, Emojis of Magic,Animal game for toddlers,Photo Mirror,Animal Book,Doodle Food Expedition.
Note: These apps (My Music And My Movies) are Inbuilt on Samsung Duos and new 7 inch Tab.
IOS APP:-Dadj, TapOff
IONIC Framework app:- AVM DEPT Connect,
React Native Apps :-PMP Mock