Originally based on LennyPenny's but now entirely rewritten.
This tool will automatically record POV demos for you when the freeze time period begins.
It will save them to: Counter-Strike Global Offensive\csgo\pov\year\month\day\map_hour_minute_second.dem, to make it easy to cross-reference with Shadowplay clips.
The program doesn't read/write to the game's memory at all. It uses Valve's own GSI api to retrieve information about the current game state and uses the Windows SendMessage function to execute console commands, to understand the latter read this.
You should run the program at least once before opening up the game to make sure that csgo\cfg\gamestate_integration_autodemo.cfg gets written properly, after that you are free to open it mid-game.
Download it here.