Some new aspects of HEVC reference pictures are a bit unclear to me, I hope someone can please explain. I have read some documentation in [1] and [2] but still unclear..

Assume Hierarchical B/P GOP structures are possible.

- Do P-frames still have only 1 reference frame ? (either a B/I frame) ? or can a P-frame have multiple (e.g. reference an I-frame and multiple B-frames) ?

- Similarly can B-frames have more than 2 reference frames ?

- Regarding the Reference Picture Set (RPS), if a B-picture has a RPS with 3 frames, then does it have to select the best 2 frames ? Are all the dependencies decided at the decoder side ?

- Is there a maximum limit to how many reference frames a picture can have ? (or is it specified by the side of the dependency picture buffer (DPB) size ?)

Many thanks

[1]R. Sjoberg, Y. Chen, A. Fujibayashi, M. M. Hannuksela, J. Samuelsson, T. K. Tan, Y.-K. Wang, and S. Wenger, “Overview of HEVC High-Level Syntax and Reference Picture Management,” IEEE Transactions on Circuits and Systems for Video Technology, vol. 22, no. 12, pp. 1858–1870, Dec. 2012.

[2] High Efficiency Video Coding (Hevc): Algorithms and Architectures (Integrated Circuits and Systems), 3 Sep 2014
by Vivienne Sze and Madhukar Budagavi