What does rescale output mean in OBS?

What Does Rescale Output Mean in OBS?

In OBS Studio, "Rescale Output" is a powerful feature that allows you to change the resolution of your stream or recording independently from your base canvas, primarily used if you want to record and stream at different resolutions.

Understanding Rescale Output in OBS

OBS Studio operates with two primary resolution settings:

Base (Canvas) Resolution: This is the resolution of your "canvas" or the workspace where you arrange your sources (games, webcams, images, etc.). It's the native resolution you're working with, often matching your monitor's resolution.
Output (Scaled) Resolution: This is the final resolution that OBS will send to your live stream or save to your recording file after all processing.

The Rescale Output setting, found within OBS's Output settings, determines this Output (Scaled) Resolution. If you enable it, OBS will take your Base Canvas Resolution and scale it either up or down to the specified Output Resolution.

Why Use Rescale Output?

Rescale Output offers significant flexibility and optimization for content creators:

Streaming and Recording at Different Resolutions: This is a primary use case. For instance, you might want to record your gameplay in a pristine 1080p or 1440p for high-quality YouTube uploads, but stream live at 720p to accommodate viewers with slower internet connections or to reduce your own upload bandwidth requirements.
Optimizing Performance: Rendering and encoding at a lower resolution requires less CPU and GPU power. If your system struggles to maintain frame rates while streaming or recording at your native monitor resolution, downscaling the output can significantly improve performance.
Meeting Platform Requirements: Different streaming platforms or recording purposes might have specific resolution recommendations or limitations. Rescale Output allows you to easily conform to these.
Bandwidth Management: Streaming at a lower resolution (e.g., 720p instead of 1080p) drastically reduces the required upload bandwidth, leading to a more stable stream with fewer dropped frames for both you and your viewers.

How Rescale Output Works

When you enable "Rescale Output" in your Output settings (either for "Streaming" or "Recording"), OBS will apply a scaling filter to your entire canvas before encoding.

Consider the following comparison:

Setting	Description	Impact
Base (Canvas) Resolution	The internal resolution where you arrange all your sources. Usually matches your monitor.	Determines the clarity of your sources within OBS.
Output (Scaled) Resolution	The final resolution of your stream or recording, after potential downscaling/upscaling from the Base Canvas. Controlled by "Rescale Output".	Determines the quality and file size of your final output. Affects performance and bandwidth.

Practical Applications and Examples

Let's look at common scenarios where Rescale Output is invaluable:

Scenario 1: High-Quality Recordings, Efficient Streams
- Goal: Record gameplay in 1440p (2560x1440) for YouTube, but stream live at 1080p (1920x1080) for Twitch.
- Setup:
  - Video -> Base (Canvas) Resolution: 2560x1440
  - Output -> Streaming -> Rescale Output: 1920x1080
  - Output -> Recording -> Rescale Output: (Unchecked or set to 2560x1440)
- Result: Your recording will be 1440p, while your live stream will be a downscaled 1080p.
Scenario 2: Reducing System Load on Older Hardware
- Goal: Stream a demanding game without dropping frames, using an older CPU/GPU.
- Setup:
  - Video -> Base (Canvas) Resolution: 1920x1080 (your monitor's resolution)
  - Output -> Streaming -> Rescale Output: 1280x720
- Result: OBS will render and encode the stream at 720p, significantly reducing the computational load compared to 1080p, leading to a smoother stream.

Important Considerations

When using Rescale Output, keep these points in mind:

Downscaling vs. Upscaling:
- Downscaling (e.g., from 1080p to 720p) generally looks good and reduces file size/bandwidth.
- Upscaling (e.g., from 720p to 1080p) is generally discouraged as it makes the image blurry or pixelated without adding any actual detail. Always strive to have your Base Resolution equal to or higher than your Output Resolution.
Downscale Filter: When downscaling, OBS uses a "Downscale Filter" (found in Video settings). Filters like Lanczos provide sharper results but use more CPU, while Bicubic or Bilinear are faster but can be softer.
Aspect Ratio: Ensure that your scaled output resolution maintains the same aspect ratio as your base canvas (e.g., 16:9 for 1920x1080 and 1280x720) to avoid distorted images.
Encoder Performance: While downscaling reduces the resolution, the encoder settings (bitrate, preset) also heavily influence the final quality and performance.

Configuring Rescale Output in OBS

Here's a step-by-step guide to setting up Rescale Output:

Open OBS Studio.
Go to File > Settings (or click the "Settings" button in the bottom right).
Navigate to the Output tab.
In the "Output Mode" dropdown, select Advanced for more control.
Choose either the Streaming or Recording tab, depending on which output you want to rescale.
Look for the "Rescale Output" checkbox.
Check the box next to "Rescale Output."
In the dropdown menu that appears, select your desired output resolution (e.g., 1920x1080, 1280x720).
Click Apply and then OK to save your settings.

Remember to set your Base (Canvas) Resolution in the Video tab first, as this is the starting point for any scaling.

Related OBS Output Settings

While Rescale Output is crucial, it works in conjunction with other settings:

Base (Canvas) Resolution: As mentioned, this is your working resolution. It's set in the Video tab.
Output (Scaled) Resolution: This is what "Rescale Output" controls.
Downscale Filter: Also in the Video tab, this filter determines how OBS reduces the image size when scaling down.
FPS (Frames Per Second): In the Video tab, this sets the frame rate for both your canvas and output.
Bitrate: In the Output tab, this controls the data rate of your stream or recording, directly impacting quality and file size/bandwidth.

By understanding and utilizing "Rescale Output," you gain greater control over your OBS productions, allowing for optimized performance, tailored content, and a better experience for your audience.