V4L Camera frame timestamp question

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Hi, 

I'm currently using the V4L-DVB driver to control a few logitech webcams and
playstation eye cameras on a Gubuntu system.

Everything works just fine except one thing:  the buffer timestamp value seems
wrong.

The way I get the timestamp value is through the v4l2_buffer struct like this:

  struct v4l2_buffer buf;
  CLEAR(buf);
  buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
  buf.memory = V4L2_MEMORY_MMAP;
  assert(ioctl(fd_, VIDIOC_DQBUF, &buf));
  
  printf("timestamp = %.3f", buf.timestamp.tv_sec + buf.timestamp.tv_usec /
1000000);

this should be the timestamp of when the image is taken (similar to
gettimeofday() function)
but the value I got is something way smaller (e.g. 75000) than what it should be
(e.g. 1275931384)


Is this a known problem?


Thanks!

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