Prerequisites & Notation

Before You Begin

This chapter applies coded caching to video streaming — the largest single category of internet traffic. Prerequisites: MAN basics, rate-distortion theory, basic video coding.

  • MAN coded caching (Ch 2)(Review ch02)

    Self-check: Can you state the memory-rate tradeoff R∗(M)R^*(M)?

  • Decentralized caching (Ch 13)(Review ch13)

    Self-check: How does random placement compare to MAN?

  • Rate-distortion theory and successive refinement(Review ch06)

    Self-check: What is a successively refinable source?

  • HTTP Adaptive Streaming / DASH

    Self-check: What is an MPD manifest?

  • Video quality metrics (PSNR, SSIM, VMAF)

    Self-check: What does VMAF measure?

Notation for This Chapter

Symbols for video streaming + coded caching.

SymbolMeaningIntroduced
LLNumber of quality layers (base + enhancement)s01
bℓb_\ellBitrate of layer ℓ\ells01
DℓD_\ellDistortion at layer ℓ\ell (rate-distortion curve)s01
QoE\text{QoE}Quality-of-Experience metric (composite)s03
ncn_cNumber of chunks per videos03
qk(t)q_k^{(t)}Quality level selected by user kk at time tts04
MMPer-user cache size (in video units)s02
← Ch 20Video as Successively-Refinable Content