mpg in the compositor not starting at right frame?

I am trying to composite 2 rendered animations together. They are an .mpg of a 200 frame Cycles animation, and a png image sequence of 200 frames of Freestyle to go with it. It is a simple camera pan test for freestyle temporal coherency, so nothing complex.

I have the freestyle image sequence brought in with an image node set to sequence, and then alpha overed the .mpg brought in with a movie input node. The problem is that they do not line up. They are both the same framerate, but something seems to be causing the .mpg to start at a later frame (seems to be 17). When I have the timeline set to frame 0, it shows the freestyle at starting position, but the frame shown for the .mpg is already after things have started moving. I know this to be the case because if I open the .mpg in VLC media player, it has the proper start position. So those opening frames are there, they just aren’t showing up in Blender for some reason.

I have tried using the Image node to bring the .mpg in instead, and also tried putting it into the Video Sequence Editor, but none of those things make a difference. There is no frame offset set, nor was there when I initially rendered it.

Is this a normal problem?

Is this a normal problem?
Given we can’t see what you see, it’s difficult to tell. Have you tried converting/rendering the .mpg to an image sequence to check if it’s an effect of using a video file.

I have not tried that, but since it works fine in media players, the video file seems to be okay. I can try converting it to an image sequence.