Content- and context-aware encoding techniques for ABR streaming

In this paper, we offer a review, classification, and comparison of the existing encoding optimization techniques for adaptive-bitrate (ABR) streaming. In our review, we will include techniques developed for adaptation to the encoding complexity of the visual content – the so-called “per-title,” “per-scene,” “content-adaptive,” and “content-aware” techniques, as well as techniques designed to adapt to network, device capability, and audience characteristics – the so-called “network-aware,” “device-aware,” and “audience-aware” techniques. Finally, we will review methods using composite optimization objectives – the so-called “context-aware” encoding techniques. In all cases, we will start with problem definition, describe common approaches developed for solving such problems, and provide performance studies results of example implementations of such algorithms.