I think "Integer Scaling" should be built into Video Size setting of the Video Format settings. We currently have "Half Size". The "Integer Scaling" would use the Width text-field for the integer number used to multiply the width of the recorded area, and the Height text-field for the integer number used to multiply the height of the recorded area.
For example, a 4x3 Integer Scalign would turn a 100x100 recording area into a 400x300 video and a single pixel (1x1) of recording area into a 4x3 of video, and a 2x2 Integer Scaling would turn a 960x540p recording area into a 1920x1080p video, without using an app like Integer Scaler, and without needing to run the app at the resulted resolution.
By integer scaling I mean that on the axis of the scaling each pixel would be multiplied by the value of the chosen integer.
Also, please let us use the percentage sign (%) in the Custom setting, like it is used in the Full Size and Half Size options.
Examples of Integer Scaling produced with the IntegerScaler app:
And another example image found on the internet: