A video-based monitoring system may dynamically adjust the resolution or frame rate of video cameras in a materials handling facility in response to changing conditions or events. The resolution or frame rate may be increased when an agent authorized to handle high-value items (e.g., expensive items or those at high risk of being stolen) enters the field of view of a given camera in the facility. The system (or a video camera thereof) may detect the presence of the authorized agent by detecting that his clothing or equipment includes a color or pattern designating such authorization using analytics applied to a video stream captured by the camera. Other pre-defined conditions or events indicating that higher-resolution video monitoring is warranted may trigger an increase in the resolution or frame rate of a camera. The resolution or frame rate may be decreased when these conditions or events no longer apply.