Webcam FPS only correct after using OBS Studio

Hi Manjaro community,

I have a 174f:2459 Syntek Integrated Camera on my Laptop (Lenovo Legion 5) which supports HD 30 FPS, but in multiple apps (guvcview, firefox using this FPS test) it only shows 15 FPS by “default”.

Only after using OBS studio and setting up a V4L2 video capture device, 30 FPS are then show in the previous apps. Eventually (like after using the camera kill switch), 15 FPS is restored and I have to open OBS again. Does anybody knows why this behavior exists?

> v4l2-ctl --list-formats-ext

ioctl: VIDIOC_ENUM_FMT
        Type: Video Capture

        [0]: 'MJPG' (Motion-JPEG, compressed)
                Size: Discrete 1280x720
                        Interval: Discrete 0.033s (30.000 fps)
                Size: Discrete 960x540
                        Interval: Discrete 0.033s (30.000 fps)
                Size: Discrete 848x480
                        Interval: Discrete 0.033s (30.000 fps)
                Size: Discrete 640x480
                        Interval: Discrete 0.033s (30.000 fps)
                Size: Discrete 640x360
                        Interval: Discrete 0.033s (30.000 fps)
                Size: Discrete 424x240
                        Interval: Discrete 0.033s (30.000 fps)
                Size: Discrete 352x288
                        Interval: Discrete 0.033s (30.000 fps)
                Size: Discrete 320x240
                        Interval: Discrete 0.033s (30.000 fps)
                Size: Discrete 320x180
                        Interval: Discrete 0.033s (30.000 fps)
        [1]: 'YUYV' (YUYV 4:2:2)
                Size: Discrete 1280x720
                        Interval: Discrete 0.100s (10.000 fps)
                Size: Discrete 960x540
                        Interval: Discrete 0.067s (15.000 fps)
                Size: Discrete 848x480
                        Interval: Discrete 0.050s (20.000 fps)
                Size: Discrete 640x480
                        Interval: Discrete 0.033s (30.000 fps)
                Size: Discrete 640x360
                        Interval: Discrete 0.033s (30.000 fps)
                Size: Discrete 424x240
                        Interval: Discrete 0.033s (30.000 fps)
                Size: Discrete 352x288
                        Interval: Discrete 0.033s (30.000 fps)
                Size: Discrete 320x240
                        Interval: Discrete 0.033s (30.000 fps)
                Size: Discrete 320x180
                        Interval: Discrete 0.033s (30.000 fps)

I know this question may seems a bit confusing/strange, feel free to ask me anything.
Thanks in advance.