[FFmpeg-user] Create a thumbnail image every X seconds of the video

[zahid mahmood]

hello i have following command to get every second images from video.

  ffmpeg -i input.flv -f image2 -vf fps=fps=1 out%d.png

this command extract whole image every second . i want to get images from
specific (x,y) position. for example i want to get images from top of left
side of video.