# Convert jpeg's to PPM files
for f in foo*.jpg; do jpegtopnm $f > `basename $f .jpg`.ppm;
done

# Combine PPM frames to YUV stream
cat *.ppm | ppmtoy4m -o 1 -F 24:1 -I t -L | yuvdenoise | mpeg2enc -B 35 -f 0 -q 5 -b 500 -a 1 -o foo.m1v

# Convert video stream from MPEG-1 video to AVI
ffmpeg -i foo.m1v foo.avi