Assumed audience
- Reading level: technical.
- Background: entropy and probability.
- Goal: understand rate-distortion tradeoffs.
Core idea
Lossy compression accepts distortion in exchange for smaller bit rates. Rate-distortion theory quantifies the best possible tradeoff.
Rate-distortion function
The function gives the minimum rate needed to achieve expected
[ E[d(X, \hat{X})] \le D. ]
Why this matters
This is the theoretical limit behind audio, image, and video compression.