Improved Huffman code tables for H.263/H.263+ based video compression applications

This paper presents new Huffman code tables to improve H.263+ video compression efficiency for two typical video source features in applications. H.263 and H.263+ standards use fixed Huffman tables regard less of quality, picture format or frame rate. Furthermore, that tables are the same for inter and intra coding, both situations with very different statistics. New Huffman t ables have been generated to code DCT coefficients for VHS quality and low bit -rate video applications that eas ily can substitute the original ones, with efficiency improvements that can reach 8% and 23% in inter and intra frames coding, respectively. They are specially interesting in H.263 and H.263+ applicat ions that need low complexity, for which H.264 could not be a good option. This is the case of the application presented in this communication, called Miravideo, from Telef6nica Spanish company, which transm its audio and video via GPRS using the new Huffman tables.