Comment by posh_somme

I've been learning Japanese for just over a year now, and its a community that might have the highest concentration of amazing free learning apps with sentence mining capabilities, many of which do things very similarly to what you're building. Have you tried some of these?

asbplayer Manatan Yomine Anki Miner AnimeCards Nagare

These are just for video, there are other similar solutions for games, manga and ebooks, and some of them are all in one