Build an offline-first Android music player that imports files from device storage, SD^? cards, computers, and optional user-controlled cloud folders. It should preserve playlists, metadata, queue state, shuffle behavior, and device migrations while performing playback entirely on the device. Sell the core player as a one-time purchase, with an optional paid migration service for importing and cleaning large libraries.

Streaming prices and access restrictions are rising while reviews across major and independent players report unreliable downloads, interrupted playback, and disappearing music. Large-capacity phone storage and SD^? cards make a locally controlled library practical again.