Eric Nassor

DASH fast start using HTTP/2

Dynamic Adaptive Streaming over HTTP (DASH) is broadly deployed on the Internet for live and on-demand video streaming services. Recently, a new version of HTTP was proposed, named HTTP/2. One of the objectives of HTTP/2 is to improve the end-user perceived latency compared to HTTP/1.1. HTTP/2 introduces the possibility for the server to push resources to the client. This paper focuses on using the HTTP/2 protocol and the server push feature to reduce the start-up delay in a DASH streaming session. In addition, the paper proposes a new approach for video adaptation, which consists in estimating the bandwidth, using WebSocket (WS) over HTTP/2, and in making partial adaptation on the server side. Obtained results show that, using the server push feature and WebSocket layered over HTTP/2 allow faster loading time and faster convergence to the nominal state. Proposed solution is studied in the context of a direct client-server HTTP/2 connection. Intermediate caches are not considered in this study.

Adaptive Streaming of HEVC Tiled Videos Using MPEG-DASH

Adaptive streaming technologies are used heavily to deliver video content over the Internet, but still face problems in networks with limited bandwidth, for videos with ultra-high definition (UHD) or greater, even when using the latest High-Efficiency Video Coding (HEVC) standard. In this paper, we propose a solution to these problems based on three things: a specific HEVC-compliant motion-constrained tiled encoding allowing tile-based decoding and rendering; a specific derivation of the ISO base media file format enabling a tile-based encapsulation and delivery; and their use in adaptive streaming of tiled video content using MPEG dynamic adaptive streaming over HTTP requiring only a single standard HEVC decoder on the client side. We present an evaluation of constrained and unconstrained HEVC tiling compression, and also of the associated packaging and streaming overheads. The results of this evaluation indicate that our approach incurs a complete overhead of at most 7.3% for UHD content, at 10 Mbps or above, when split in 25 tiles, and only 3.5% for nine tiles, when compared with the streaming of the non-tiled video. Our approach also comes with a small impact on client-side players but provides the interesting benefit of being able to deliver UHD videos over bandwidth-constrained networks adaptively, based on its tiled content.

Low-Complexity Intra Coding for Scalable Extension of HEVC Based on Content Statistics

This paper presents a new approach for a scalable extension of High Efficiency Video Coding (HEVC) intra pictures. The proposed scalable intra codec targets very low complexity together with coding efficiency, and thus employs only one prediction mode, known as inter layer intra prediction. The main novelty of the codec is a new fast rate-distortion optimization approach, which is founded on the rate-distortion theory. It exploits precomputed offline information for the reduction of the computational complexity, and a new allocation process for the balancing of the coded information. The precomputed information is a set of optimal quantifiers and associated rate-distortion curves for predetermined statistical models that are used for efficiently coding the Discrete Cosine Transform channels. This low-complexity intra coding tool has been proposed to the scalable HEVC call for proposals. In the scalable standard testing conditions, the proposed intra codec shows compression performance with a bit-rate increase of around 10% only compared with the HEVC single-layer encoder.