Multi-resolution motion estimation at low bit-rates

The performance of multi-resolution motion estimation schemes in low bit-rate video coding are presented. Video frames are individually wavelet decomposed and motion activity is detected using variable block size multi-resolution motion estimation (MRME) schemes. The residual frames are coded using zero tree quantization, followed by arithmetic entropy coding. The MRME schemes are shown to exploit the motion correlation among subbands of different scales. We show that the MRME schemes behave differently, than as shown by Zafar et al. (1993), in low bit rate applications employing zero tree quantization. Simulation results are provided for coding of QCIF resolution (176/spl times/144 pixels) video frames at 10 frames/sec, coded at various low bit-rates. Four different MRME schemes are evaluated and performance comparisons are provided for several low output bit-rates.