Comparisons of the H.264 and H.263 Video Compression Standards

The International Telecommunications Union (ITU-T) and the International Standardization Organization/International Electrotechnical Commission (ISO/IEC) are the only two formal organizations that developed video coding standards. The ITU-T video coding standards called recommendations and are usually optimized for real-time video communication such as videoconference and video telephony while the ISO/IEC standards are mainly designed for storage (DVD) and broadcast (satellite and digital TV). ITU-T and the ISO/IEC JTC1 have agreed to join their efforts in the development of H.264 standard, which was initiated by ITU-T committee. The ITU-T H.264 video coding standard has been developed to achieve significant improvements over the existing standards in compression performance, although the basic coding framework of the standard is similar to that of the existing standards. H.264 standard is compared with H.263 and test results showed the coding gains obtained by the H.264 encoder is over the H.263 encoder for Common Intermediate Format (CIF) and Quarter Common Intermediate Format (QCIF)sequences, respectively. H.264 achieves an average of 4 dB PSNR(peak signal-to-noise rate) gain for the selected ten CIF sequences at 30 frames per second, and 4.57 dB Peak Signal–to–Noise Rate (PSNR) gain for the selected ten QCIF sequences at 30 frames per second.