OBS NVENC Multipass Mode Explained

This article explains the “Multipass Mode” setting in the NVENC encoder within OBS Studio. It covers how this setting works, the differences between its three configuration options—Disabled, Quarter Resolution, and Full Resolution—and how to choose the best option to balance your stream’s visual quality and your computer’s GPU performance.

What is Multipass Mode?

Multipass Mode is a setting for NVIDIA’s hardware encoder (NVENC) in OBS Studio that determines how the encoder analyzes video frames to distribute your allocated bitrate. Instead of encoding the video blindly in a single pass, multipass settings allow the encoder to evaluate the complexity and motion of the frame before performing the final encode. This results in a cleaner, less pixelated image during high-motion scenes without requiring you to increase your overall bitrate.

The Three Multipass Mode Settings

OBS Studio offers three options for Multipass Mode:

• Disabled (Single Pass): The encoder processes the video in a single pass. This mode uses the absolute minimum amount of GPU resources. While highly efficient, it may result in macroblocking (pixelation) during fast-paced gameplay because the encoder cannot anticipate sudden motion.
• Two Passes (Quarter Resolution): The encoder performs a quick first pass at one-quarter of your output resolution to map out motion and detail, followed by the final encoding pass. This setting provides a major boost in visual clarity with only a negligible impact on GPU performance.
• Two Passes (Full Resolution): The encoder analyzes the video at your maximum output resolution before encoding. This delivers the highest possible image quality, capturing the finest details and minimizing compression artifacts. However, it requires the most GPU processing power.

Impact on Performance and Quality

Multipass Mode does not change your actual bandwidth or stream bitrate; instead, it optimizes how those bits are spent.

To run the second pass, NVENC utilizes your graphics card’s CUDA cores. If your GPU is already running at 100% capacity due to a demanding game, enabling “Two Passes (Full Resolution)” can lead to overloaded GPU warnings and dropped frames in OBS.

Which Setting Should You Choose?

• Two Passes (Quarter Resolution): This is the recommended “sweet spot” for the vast majority of streamers. It offers nearly the same visual quality as Full Resolution but keeps GPU overhead incredibly low.
• Two Passes (Full Resolution): Choose this if you have a high-end, modern NVIDIA graphics card (RTX 30-series, 40-series, or newer) and your GPU usage while gaming and streaming remains comfortably below 90%.
• Disabled: Use this if you are using an older GPU, playing highly demanding games at maximum settings, or experiencing “Encoding Overloaded” warnings in OBS Studio.