[FFmpeg-user] how can I set limit_filesize or recording_timefor the specific output dynamically?

[Huang Soho]

perhaps you need make the keyframe at every 3 second.
>

It is impossible to set key frame since the video frame is capture from
usb webcam and do stream copy.
Is there any other idea ?
it seems many limitation about "segment muxer" .
why it can not used when capture from usb webcam and stream copy?