Adaptive Deblocking Filter

1. Adaptive Deblocking Filter Peter List, Anthony Joch, Jani Lainema, Gisle Bjøntegaard, and Marta Karczewicz IEEE TRANSACTION ON CIRCUIT AND SYSTEM JULY, 2003

2. Outline • Introduction • Boundary analysis • Filtering • Result • Conclusion

3. Introduction • Blocking artifacts • discontinuities on the edges of the blocks • Source of blocking artifacts • block-based integer discrete cosine transforms (DCTs) • motion compensated prediction

4. Introduction • two approaches to integrate deblocking filters into video codec • post filters • only operate on the display buffer outside of the coding loop • loop filters • operate within the coding loop

5. Introduction • Loop filtering has several advantages over post filtering • guaranteea certain level of quality • no need for an extra frame buffer in the decoder • typically improve both objective and subjective quality

6. Boundary analysis • error distribution in a 4 x 4 block • coding errors are larger near the block boundaries than in the middle of the block

7. Boundary analysis • H.264 deblocking filter is adaptive on several levels • slice level • block-edge level • sample level

8. Boundary analysis • block-edge level

9. Boundary analysis • sample level

10. Boundary analysis • slice level

11. Boundary analysis