V4l2 how to read frames at a certain frequency?

Question

linux

How can I set a certain FPS for the camera using v4l2?
I'll learn the documentation by heart soon, but I can't answer my own question.
I use the mmap method to read frames.
Here is a link to the documentation: v4l2spec.bytesex.org/spec-single/v4l2.html#BUFFER
There is a Timecodes section just below. At first glance, it might seem that this is it. But the v4l2_buffer.timecode field is not used, because the buffers.flags & V4L2_BUF_FLAG_TIMECODE flag is 0, and this flag is set by the driver itself, it cannot be set manually.
PS3Eye camera: en.wikipedia.org/wiki/PlayStation_Eye
It is necessary to record video through it at a frequency of 60 Hz, but now, when I read frames from it, it turns out about 30 frames per second. I measure FPS manually using the gettimeofday timer.

Answer 1

Well, found the answer: v4l2spec.bytesex.org/spec-single/v4l2.html#VIDIOC-G-PARM timeperframe
field