I have a Canon Rebel T3 and everything was working fine when today I took it out to take some shots half of my pics and videos are black nothing is stuck the mirror mechanisam seems to work fine .. does anyone know what it could be?
You say nothing is stuck, but the sample images look almost certainly like you have a shutter curtain that is not fully opening. The amount of frame that is blocked seems to be variable as well.
Have you looked at the sensor with the camera in Live View mode and the lens removed? Can you see the entire sensor or is part of one of the shutter curtains blocking the top of the sensor? (The top of the sensor inside the camera is the bottom of the frame of photos and videos, since the lens inverts the image).
If there is nothing in front of the sensor when the mirror is up for Live View, then the problem is in the sensor itself or in the camera's LCD screen.
From comments by the OP:
I wish I could send you a picture because I’m a beginner and I don’t understand how things should be aligned .. when I take off the lens and put it in Live mode one part goes up and a little part is down ... sorry about my description but I’m trying my best .. help ?!
A little part from the main mirror is open and it’s a little mirror .. wow I really hope I’m explaining this well .
With your further description it sounds like the secondary mirror, which should fold up flat against the main mirror, is not flipping up properly. The camera will need to be repaired by a competent repair service or replaced.