Sets the high quality setting bitrate of a few resolutions to 90mbps and their medium quality setting to 60mbps.
Put autoexec.ash in the root of your sd card. IMPORTANT: if you are on windows you must save page as (download) this file, if you copy paste its contents it will not work because it needs to have unix line endings (and an empty line at the end). If you want to edit this file, get an editor like Notepad++ that supports unix line endings.
For how to set custom bitrates see: bitrate_table.txt
Switch to an updated resolution and you will notice that the indicated time left is lower (1h30 instead of 2h if you have an empty 64gb card). You may need to start recording before it shows the updated time.