Getting capture fps as 30

arunkrishna — Mon, 18 Mar 2013 11:53:46 GMT

Hi,

I am using IMX6QUAD SABRE board for Auto infotainment.

I am using the freescale sample application "mxc_v4l2_tvin.c" to capture and display.This is provided along with the BSP.

I am capturing using a composite cable through the CVBS port and displaying it on the LVDS.

When I profile the code I am getting a performance of 30fps for capture.

However I feel that capture should hapen at 60 fps.

When I checked the file "mxc_v4l2_tvin.c" I see that we are sending frame rate to the driver through an ioctl.Please find below the part of the code

parm.parm.capture.timeperframe.numerator = 1;

parm.parm.capture.timeperframe.denominator = 0;

....

if (ioctl(fd_capture_v4l, VIDIOC_S_PARM, &parm) < 0)

However even I change the denominator in the above code to 60 ,30 or to 15,there is no change in the frame rate.It still remains at 30

Query:

1)Does capture always happen at 30fps?Is there any way to make it 60fps?

2)I also tried changing some parts of the driver code inside drivers/media/video/mxc/capture/mxc_v4l2_capture.c and adv7180.c files.

However these changes does not get affected.Please let me know which files should i have a look at.

I have attached the file for refrence.

Thanks in advance

ARUN KRISHNA

Original Attachment has been moved to: mxc_v4l2_tvin.c.zip

Re: Getting capture fps as 30

ChucoChe — Fri, 03 May 2013 21:43:39 GMT

Hi,

NTSC 480i can only be captured at 30fps. 480p should be captured at 60fps.

You can enable echo 1 > /sys/…/vdi_rate_double and generate a frame per each odd and pair in the interlaced format making it look like 60fps.

Michel