Can't limit the fps value when recording?

I have tried the command line to enter
`scrcpy --max-fps = 60 -record file.mp4. `
But the recorded video is around 30fps.
Then I went to check the source code and found that the recording is just writing the received Packet, and there is no place to set fps.
Does this mean that the recorded fps is entirely dependent on the refresh rate of my screen?
But oddly enough, if I don't limit the` --max_fps`, the video I record is only about 12fps.

Start by reproducing the recording behavior with the command shown, then trace how --max-fps and received packets reach the recording path in the source. Compare the recorded frame rate with the received frame rate. Done means the expected relationship between the frame-rate limit and recorded output is established and the reported behavior is resolved or clearly documented.

Written by the indexing model from the issue text.