What makes AVC better than MPEG-2?
AVC uses MPEG-2 block-based processing with motion-predictive compensation. AVC takes these basic MPEG-2 principles and adds refinements and some new features. The most significant gain comes from the enhanced motion-compensated prediction, which results in less residual errors to convey. The following summary captures the main enhancements: * Multiple ME block sizing options – to track objects more accurately * Quarter pixel motion prediction – better accuracy * Multiple reference frames – to help find better matches * 4×4 transform block – less errors * New intra prediction modes – smaller I frames * In loop de-blocking filter – to conceal heavy compression artifacts * Context Adaptive Binary Arithmetic Coding (CABAC) – provides better entropy coding The effect of all of this, plus a large number of smaller enhancements, is a bandwidth saving of at least 50%, when compared to any other standard at the same video quality.
