H.264 Inter-Frame Coding: Motion Estimation and Compression Algorithms

Inter-frame coding serves as a fundamental component of H.264/AVC video compression, employing advanced algorithms to significantly reduce file sizes while preserving visual quality. This technique implements motion-compensated prediction where encoders analyze macroblocks (typically 16x16 pixels) to identify motion vectors between consecutive frames. Instead of encoding complete frames, the system calculates and stores only residual data representing differences from reference frames using discrete cosine transform (DCT) and quantization processes. The implementation involves key functions like motion estimation through integer-pixel and sub-pixel search algorithms, followed by entropy coding (CAVLC or CABAC) for efficient bitstream representation. This approach achieves superior compression ratios compared to intra-frame-only methods, particularly optimizing complex scenes with multiple moving objects through adaptive block size partitioning (from 4x4 to 16x16 macroblocks). Consequently, inter-frame coding enables smoother playback experiences while maintaining efficient storage utilization, making it a cornerstone of modern video compression technology.