What is OBS Studio Fractional Framerate?

This article explains the purpose and function of the fractional framerate setting in OBS Studio’s video settings. You will learn how this setting works, why it is essential for specific broadcasting and video editing workflows, and how to configure it to avoid synchronization issues in your video production.

In OBS Studio, the fractional framerate setting allows users to define a highly precise, non-integer frames-per-second (FPS) value using a numerator and a denominator. While standard settings offer whole numbers like 30 or 60 FPS, the fractional setting is used to achieve legacy television and broadcast standards, most notably NTSC formats such as 29.97 FPS or 59.94 FPS.

Why Fractional Framerates are Necessary

The need for fractional framerates dates back to the introduction of color television. To prevent interference between the color signal and the audio signal in the NTSC system, the frame rate was slightly reduced by a factor of 1000/1001. This resulted in the standard broadcast rates we use today:

• 29.97 FPS (calculated as 30,000 / 1,001)
• 59.94 FPS (calculated as 60,000 / 1,001)

If you are streaming or recording content that will be integrated with television broadcasts, legacy AV hardware, or hardware capture cards, matching these exact fractional rates is crucial.

Preventing Audio and Video Desynchronization

One of the primary reasons to use fractional framerates in OBS Studio is to prevent encoding and editing issues. If you record video at a flat 60 FPS but your capture card or camera outputs at 59.94 FPS, OBS must duplicate or drop frames to compensate. Over long recording sessions, this mismatch can lead to gradual audio-video desynchronization or subtle visual stuttering.

Furthermore, professional video editing software—such as Adobe Premiere Pro, DaVinci Resolve, or Final Cut Pro—often defaults to NTSC timelines (29.97 or 59.94 FPS). Importing a true 60 FPS video into a 59.94 FPS timeline can result in rendering issues, skipped frames, or misplaced audio cuts. Setting OBS to the matching fractional framerate ensures a seamless post-production workflow.

How to Configure Fractional Framerate in OBS Studio

To enable this setting in OBS Studio:

1. Open Settings in the bottom right corner of OBS.
2. Navigate to the Video tab on the left menu.
3. Locate the FPS Values dropdown menu (which defaults to “Common FPS Values”).
4. Change this dropdown to Fractional FPS Values.
5. Input your desired values. For example, for 59.94 FPS, set the Numerator to 60000 and the Denominator to 1001. For 29.97 FPS, use 30000 and 1001.
6. Click Apply and then OK.

For standard internet streaming to platforms like YouTube or Twitch, integer rates like 30 or 60 FPS are perfectly acceptable. However, for professional broadcasting, multi-camera setups, and precise post-production, the fractional framerate setting is an essential tool for maintaining video fidelity and synchronization.