This is an OST from Irozuku Sekai no Ashita Kara.
You can watch it HD
Wallpaper is from the same anime.
You can find the wallpaper here:
https://www.zerochan.net/2451636
http://i67.tinypic.com/fljy0w.jpg
This video is made by me, i hope u will like it 🙂