Tool made and improved by multiple people(i'm not one of them). This is a chrome extension that helps time RTA.

Installing

1. Extract the .zip file to a folder of your choosing.
2. Go to chrome://extensions/.
3. Enable the developer mode toggle on the top right.
4. Click "Load unpacked" in the top left.
5. Select the folder you extracted the .zip file to.
6. Done. Click the icon in the extensions menu when on a youtube or twitch video page and the timer window should appear.

Using Position the window anywhere you want by clicking and dragging on the header. The plugin will remember this position for the next time.

1. Go to the first frame of the period you want to time. (on twitch you can use the frame skip buttons. On youtube you can use the frame skip buttons or the period/comma keys on your keyboard)
2. Click "mark in" to set the time.
3. Go to the last frame of the period you want to time.
4. Click "mark out" and it should show the calculated time next to the timer icon.