In current interframe video compression systems, the encoder performs predictive coding to exploit the similarities of successive frames. The Wyner-Ziv Theorem on source coding with side information available only at the decoder suggests that an asymmetric video codec, where individual frames are encoded separately, but decoded conditionally (given temporally adjacent frames) could achieve similar efficiency. We report results on a Wyner-Ziv coding scheme for motion video that uses intraframe encoding, but interframe decoding. In the proposed system, key frames are compressed by a conventional intraframe codec and in-between frames are encoded using a Wyner-Ziv intraframe coder. The decoder uses previously reconstructed frames to generate side information for interframe decoding of the Wyner-Ziv frames.