Linux uvcvideo driver - how to set custom (4 sec) keyframe interval for c920

Question

I need to stream video from my logitech c920 camera to Youtube using RTMP. I'm using avconv for that purpose. I don't want to reencode the media, because my stream is running on raspberry pi 3 which compute power is limited. My camera has builtin h264 encoder. I'm able to configure this encoder settings using guvcview, but I don't know how to configure keyframe interval that works with avconv. Youtube throws an error that my keyframe interval too long - it's 10 sec and Youtube require it to be at least 4 sec.

I read this https://github.com/raspberrypi/linux/issues/593 github discussion, but my v4l2-ctl doesn't have h264_i_frame_period control setting.

There is whole output from v4l2-ctl --all

v4l2-ctl --all
Driver Info (not using libv4l2):
        Driver name   : uvcvideo
        Card type     : HD Pro Webcam C920
        Bus info      : usb-3f980000.usb-1.5
        Driver version: 4.9.41
        Capabilities  : 0x84200001
                Video Capture
                Streaming
                Extended Pix Format
                Device Capabilities
        Device Caps   : 0x04200001
                Video Capture
                Streaming
                Extended Pix Format
Priority: 2
Video input : 0 (Camera 1: ok)
Format Video Capture:
        Width/Height      : 640/480
        Pixel Format      : 'MJPG'
        Field             : None
        Bytes per Line    : 0
        Size Image        : 614400
        Colorspace        : sRGB
        Transfer Function : Default
        YCbCr/HSV Encoding: Default
        Quantization      : Default
        Flags             : 
Crop Capability Video Capture:
        Bounds      : Left 0, Top 0, Width 640, Height 480
        Default     : Left 0, Top 0, Width 640, Height 480
        Pixel Aspect: 1/1
Selection: crop_default, Left 0, Top 0, Width 640, Height 480
Selection: crop_bounds, Left 0, Top 0, Width 640, Height 480
Streaming Parameters Video Capture:
        Capabilities     : timeperframe
        Frames per second: 24.000 (24/1)
        Read buffers     : 0
                     brightness (int)    : min=0 max=255 step=1 default=-8193 value=128
                       contrast (int)    : min=0 max=255 step=1 default=57343 value=128
                     saturation (int)    : min=0 max=255 step=1 default=57343 value=128
 white_balance_temperature_auto (bool)   : default=1 value=1
                           gain (int)    : min=0 max=255 step=1 default=57343 value=0
           power_line_frequency (menu)   : min=0 max=2 default=2 value=2
      white_balance_temperature (int)    : min=2000 max=6500 step=1 default=57343 value=4000 flags=inactive
                      sharpness (int)    : min=0 max=255 step=1 default=57343 value=128
         backlight_compensation (int)    : min=0 max=1 step=1 default=57343 value=0
                  exposure_auto (menu)   : min=0 max=3 default=0 value=3
              exposure_absolute (int)    : min=3 max=2047 step=1 default=250 value=250 flags=inactive
         exposure_auto_priority (bool)   : default=0 value=1
                   pan_absolute (int)    : min=-36000 max=36000 step=3600 default=0 value=0
                  tilt_absolute (int)    : min=-36000 max=36000 step=3600 default=0 value=0
                 focus_absolute (int)    : min=0 max=250 step=5 default=8189 value=0 flags=inactive
                     focus_auto (bool)   : default=1 value=1
                  zoom_absolute (int)    : min=100 max=500 step=1 default=57343 value=100

Any ideas how to change the keyframe interval without reencoding the media? Help please :-)