This paper presents an error resilient H.263 video compression system over noisy channels. We develop a video segment regulation algorithm at the decoder to efficiently identify and correct erroneous start codes and block addresses. In addition, a parity-embedded error detection technique is also implemented to enhance the error detection capability of the decoder at the macroblock-layer. After performing above two approaches, the decoder can report the accurate addresses of detected corrupt blocks back to the encoder via a feedback channel. With these negative acknowledgments, the precise error tracking algorithm is developed at the encoder to precisely calculate and trace the propagated errors for INTRA refreshing the contaminated blocks. Simulation results show that the proposed system yields significant video quality improvements over the motion compensated concealment by PSNR gains of 4 to 6 dB at bit rate around 32 kbps in error-prone DECT environments. In particular, this system complies with the H.263 standard and has the advantages of low memory requirement and computation complexity that are suitable for practical real-time implementation.