Intraframe low bit rate video coding robust to packet erasure

Abstract

Summary form only given. A real-time, low bit rate, intraframe video codec that is robust to packet erasure is developed for coding and QCIF gray scale video sequences. The system combines subband image coding, entropy coded scalar quantization, subband trees of wavelet coefficients, runlength coding, and Huffman coding. The encoded bit stream is encapsulated in independent variable-length packets. Isolation of spatially related trees of subband coefficients makes the system robust to packet erasure. The design objectives are to use a small encoding rate, recover gracefully from erasures in which packets of data have been erased, and have a software-only implementation that runs in real-time. The packet loss rate can be as large as 30%. We investigate several passive methods of recovering from packet erasures, including (i) replace missing pixels by the subband mean, (ii) replace missing pixels with the most recently received subband pixels in previous frames, (iii) explicit error control coding of the lower frequency subbands, and (iv) the use of interpolation and a one-frame delay to estimate the erased subband pixels.