FPS Image acquisition toolbox

Hello,

I'm using the image acquisition toolbox to acquire video from a PAL camera. I'm absolutely sure that the sensor has 25 fps (VLC also confirmed) but when I start the video preview the FPS is stationary around a value of 12.5, as it acquires one frame every two.

I tried using:

% Access an image acquisition device.
vidobj = videoinput('winvideo', 1);

% Configure the number of frames to log.
vidobj.FramesPerTrigger = 50;

% Skip the first few frames the device provides
% before logging data.
vidobj.TriggerFrameDelay = 5;

% Access the device's video source.
src = getselectedsource(vidobj);

% Determine the device specific frame rates (frames per second) available.
frameRates = set(src, 'FrameRate')

but the frame-rate property is not supported.

How can i fix this?

Thank you in advance.