How do I reformat an old camcorder video so that Iphoto recognizes the format?

I have DVDs of video recordings from the 50's and 60's that were transposed to 16 mm film. They are on a dvd now and I am trying to get Iphoto9 to recognize the format, but unsuccessful. I also tried dragging the video directly into IMovie but that didn't work out either. How do I reformat the dvd so that IPhoto9 will accept the download?