A Hybrid Stereoscopic Video Coding Scheme Based on MPEG-2 and HEVC for 3DTV Services

Recently, 3DTV has drawn much attention as a new broadcasting service. In spite of technical advances in 3DTV broadcasting services, there are two barriers that hinder the new services from being launched for terrestrial broadcasting: the lack of available bandwidth for transmission of additional-view video via terrestrial channel and backward compatibility with the legacy 2-D HDTV services. As an alternative, a hybrid stereoscopic video coding scheme is proposed for a stereoscopic 3DTV service, where one-view video is transmitted through the legacy broadcasting systems and the other one is delivered via broadband networks to which TV terminals are connected. In this paper, the proposed hybrid stereoscopic video coding scheme incorporates an MPEG-2 codec for backward compatibility with a legacy 2-D HDTV service and an HEVC codec with inter-view prediction coding as an extension to encode additional-view video sequences with high coding efficiency. The proposed inter-view prediction coding scheme in the extended HEVC incorporates an advanced motion and disparity vector prediction (AMDVP) method for enhanced motion- and disparity-compensated coding. The experimental results demonstrate that the proposed hybrid stereoscopic video coding scheme achieves an average coding efficiency of 38.22% (32.86%) in BD-rate or 1.394 dB (1.235 dB) in BD-PSNR for the out-band (in-band) scenario.

I. Introduction

With the advances in broadcasting technology, terrestrial 3DTV broadcasting services are expected to be popular in the near future. Actually, the experimental broadcasting for 3DTV services with HD quality has recently been started over the existing terrestrial DTV broadcasting systems [1], [2]. Some problems, however, arise in deploying terrestrial 3DTV broadcasting services over the legacy DTV broadcasting systems, which include a backward compatibility problem with the existing 2-D HDTV service and a bandwidth allocation problem. Both MPEG-2 and H.264/AVC video standard are currently used for the 2-D HDTV services in many countries [3]–[5]. One single 2-D HDTV program is transmitted in one frequency band of 6 MHz in Advanced Television Standards Committee (ATSC) standard [6] and 8 MHz in EBU standard [7] for terrestrial TV broadcasting. For stereoscopic 3DTV services with an HD quality, it is not possible to accommodate into the same frequency band the additional MPEG-2 video streams for the other view sequences in a similar HD quality. Fig. 1 illustrates the examples of bitrate allocations in one single 6-MHz channel for 2-D HDTV and in-band stereoscopic 3DTV services over traditional terrestrial broadcasting systems. In Fig. 1(a), a 2-D HDTV program is transmitted in one single frequency band of 6 MHz that maximally allows for 19.39-Mb/s transmission rate where an MPEG-2 video stream takes about a data rate of 17–18 Mb/s [3]. Fig. 1(b) shows an in-band delivery scenario of dual video bitstreams in a same frequency band, in which one is an MPEG-2 video stream (generally used for encoding left-view sequences) and the other one is an H.264/AVC stream for right-view sequences. Fig. 1.

Bitrate allocation examples in one single 6-MHz channel for an 2-D HDTV service and an in-band stereoscopic 3DTV service. (a) Bitrate allocation for 2-D HDTV service. (b) Bitrate allocation for 3DTV service.