tl;dr: H.264 achieves massive compression through a combination of techniques: quantization in the frequency domain (discarding high-frequency details the eye barely notices), chroma subsampling (storing color at quarter resolution since humans perceive brightness more acutely than color), and motion compensation (encoding only I-frames plus motion vector deltas for intermediate P/B-frames). A final lossless entropy encoding step compresses the redundant output. The article demonstrates this with a 5-second 60fps video of Apple's homepage compressed to 175KB—smaller than a single PNG screenshot of one frame.