Question / Help Is Rescale Output applied after or before encoding?

K2Core

New Member
Hi! I would like to use OBS for recording and streaming. Under video tab I have setted up my full resolution (1080p) and then created presets under Output for streaming and recording.
The question is: Is Rescale Outpout under Outpout > Streaming applied before or after encoding?
I want to stream in 900p or even 720p, because I'm playing fast paced shooters and under bitrate limitations of Twitch (6000) it just looks like mud in 1080p, so i prefer to use that bytes for more information about in-between frames and framerate. But I don't know if that option changes the size of the image and then encodes it (how I would like it) or just takes the final encoded frame and then make it smaller (so the bitrate is used for pumping the 1080p before rescale).

I know for sure that changing the resolution under Video tab scales it beforehand, but then I have to change it every time i want to stream (900p) or record (1080p), so it's just hustle and I forget about it most of the time.
 

carlmmii

Active Member
It resizes first, then sends that resized image to the encoder.

Be aware though that this resizing step does use the CPU for the rescaling operation, so it's quite a bit more of a hit than other rescaling operations (such as under the video tab).

For the situation where you're recording and streaming though, this is really your only option if you're doing it simultaneously. For either/or, you can use the video tab's method for rescale to improve performance if necessary, but as you've noticed it can become a bit of a pain to keep up with.
 

K2Core

New Member
It resizes first, then sends that resized image to the encoder.

Be aware though that this resizing step does use the CPU for the rescaling operation, so it's quite a bit more of a hit than other rescaling operations (such as under the video tab).

For the situation where you're recording and streaming though, this is really your only option if you're doing it simultaneously. For either/or, you can use the video tab's method for rescale to improve performance if necessary, but as you've noticed it can become a bit of a pain to keep up with.
Thank you for your help m8! That clears all my doubts, have a great day!
 

Suslik V

Active Member
And usually, the 720p still encoded faster than 1080p if only software (CPU) encoders are used. For some encoders the Rescale option of OBS Studio may not available (it's normal).
 
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