Video codecs that use motion compensation have shown PSNR gains from the use of multiple frame prediction, in which more than one past reference frame is available for motion estimation. In dual frame motion compensation, one short-term reference frame and one long-term reference frame are available for prediction. In this paper, we propose a dual frame motion compensation technique that allocates bits unevenly among frames to periodically create a high-quality frame that serves as the long-term reference frame for some time. By modifying an MPEG-4 encoder to use this technique on a set of video sequences, we show that it outperforms a normal dual frame motion compensation scheme in which the long-term reference frames are regular frames that are not allocated any extra rate.

A dual-frame video coder employs two past reference frames for motion compensated prediction. Compared to conventional single frame prediction, the dual-frame encoder can have advantages both in distortion-rate performance and in error resilience. In previous work, it was shown that optimal mode selection can enhance the performance of a dual-frame encoder. In another strand of previous work, it was shown that uneven assignment of quality to frames, to create high-quality (HQ) long-term reference frames, can enhance the performance of a dual-frame encoder. In this letter, we combine these two strands and demonstrate the performance advantages of optimal mode selection among HQ frames for video transmission over noisy channels.

Video codecs that use motion compensation have shown PSNR gains from the use of multiple frame prediction, in which more than one past reference frame is available for motion estimation. In dual frame motion compensation, one short-term reference frame and one long-term reference frame are available for prediction. In this paper, we propose a dual frame motion compensation technique that allocates bits unevenly among frames to periodically create a high-quality frame that serves as the long-term reference frame for some time. By modifying an MPEG-4 encoder to use this technique on a set of video sequences, we show that it outperforms a normal dual frame motion compensation scheme in which the long-term reference frames are regular frames that are not allocated any extra rate.

When losses occur in a transmission of compressed video, the decoder can attempt to conceal the loss by using spatial or temporal methods to estimate the missing macroblocks. We consider a multi-frame error concealment approach which exploits the uneven quality in the two reference frames to provide good concealment candidates. A binary decision tree is used to decide among various error concealment choices. The uneven quality of the reference frames provides an advantage for error concealment.

Abstract-Standard video coders often use the immediate past frame as a reference frame with motion compensation for video encoding. In this paper, we use dual reference frame motion compensation in the context of high bandwidth to low bandwidth switching such as from an Ethernet connection to a GPRS system. The implementation is based on MPEG-4. Simulation results show that there is a significant gain in the PSNR for relatively static video sequences.