LESSON wm.2.1 · Theory · 120 min
JEPA: why not predict pixels directly?
JEPA: why not predict pixels directly?. Learn joint embeddings, context encoder, target encoder, predictor, and collapse prevention and complete: Compare pixel reconstruction and r
Learning objectives
- Explain what problem “JEPA: why not predict pixels directly?” solves without hiding behind terminology.
- Trace the variables and causal links across joint embeddings, context encoder, target encoder.
- Complete “Compare pixel reconstruction and representation-prediction objectives” and judge the result with evidence rather than intuition.
Core concepts
joint embeddings
joint embeddings supports prediction in representation space: the context encoder reads visible regions, the target encoder supplies stop-gradient targets, and the predictor estimates masked or future content from context and position. Anti-collapse design must prevent every input from mapping to the same representation.
context encoder
context encoder supports prediction in representation space: the context encoder reads visible regions, the target encoder supplies stop-gradient targets, and the predictor estimates masked or future content from context and position. Anti-collapse design must prevent every input from mapping to the same representation.
target encoder
target encoder supports prediction in representation space: the context encoder reads visible regions, the target encoder supplies stop-gradient targets, and the predictor estimates masked or future content from context and position. Anti-collapse design must prevent every input from mapping to the same representation.
predictor
predictor supports prediction in representation space: the context encoder reads visible regions, the target encoder supplies stop-gradient targets, and the predictor estimates masked or future content from context and position. Anti-collapse design must prevent every input from mapping to the same representation.
and collapse prevention
and collapse prevention supports prediction in representation space: the context encoder reads visible regions, the target encoder supplies stop-gradient targets, and the predictor estimates masked or future content from context and position. Anti-collapse design must prevent every input from mapping to the same representation.
Build and verify
Compare pixel reconstruction and representation-prediction objectives
- Predict: write the expected output, trend, or failure before running code.
- Build: implement only the minimum components needed to answer the question.
- Verify: compare with a baseline or trusted implementation; save seeds, parameters, and raw outputs.
- Transfer: change one shape, dataset, scale, or workload condition and explain whether the conclusion still holds.