Will a lower resolution while rending cut down rendering time

Question

Currently I am recording screencast in fullscreen and my resolution is 1920 x 1080, which means I can render in 1080p.

For me 720p is already acceptable if this means that this will cut down in rendering times. But from what I have heard is that changing the resolution while rendering will always result in longer render times.

So the question here is, should I stick with 1080p, because my raw video file is also 1080p, or can I change my render settings to output 720p and cut down on render time.

Answer 1

Rendering in lower resolution will

1. Downscale the video, which takes very little additional processing time
2. Take less per frame time for the video encoder to compress

You should definately notice a significant gain in rendering speed if you switch from 1080p to 720p, and I cannot imagine what the other person meant, by "will always result in longer rendering times".

Of course if you cancel a rendering process which is 95% through, just to change the resolution, you will not have gained much, since the renderer has to start all over again.

Also there might be some video software on the market which is so incredebly bad that the situation I described above is reversed. But this shouldn't be the case, especially if you render with video codecs like h264, which always need a lot of processing time.