ffmpeg -f image2 -i test.png -pix_fmt yuv420p test.yuv
To convert AVI to YUV you can use the lav2yuv program. In Ubuntu Linux this program is in mjpegtools package. This is the way to convert:
lav2yuv myfile.avi > myfile.yuv
Use the ffmpeg tool:
ffmpeg -s 176x144 -i kuuba_maisema_25fps_qcif.yuv -vcodec mpeg4 -sameq -aspect 4:3 ~/kuuba.avi
You need to specify the video dimensions (176 × 144), the video codec (mpeg4), and the aspect ratio (4:3).
Use the mencoder tool:
mencoder Bike1.mp4 -ovc lavc -oac lavc -o NewBike1.avi