Passive stereoscopic displays create the illusion of three dimensions by employing orthogonal polarizing filters and projecting two images onto the same screen. In this article, a coding scheme targeting depth-enhanced stereoscopic video coding for polarized displays is introduced. We propose to use asymmetric row-interleaved sampling for texture and depth views prior to encoding. The performance of the proposed scheme is compared with several other schemes, and the objective results confirm the superior performance of the proposed method. Furthermore, subjective evaluation proves that no quality degradation is introduced by the proposed coding scheme compared to the reference method.

The MVC+D extension of the Advanced Video Coding (H.264/AVC) standard enables multiview-and-depth 3D video coding but specifies that all views are coded at equal spatial resolution. In mixed resolution 3D video coding some of the views are coded at reduced resolution. This paper proposes an improvement for the mode decisions in depth encoding in the mixed resolution scenario. We modify the distortion calculation for rate-distortion optimized depth coding. The proposed solution optimizes the depth data compression with assumption that it will be used not only for view synthesis but also for depth-based super resolution in the post-processing stage. The algorithm is implemented on top of the mixed resolution 3D video encoder based on the 3DV-ATM reference software. Evaluation of the proposed solution, tested under the JCT-3V common test conditions, is done against the mixed resolution MVC+D coding with the view synthesis distortion enabled. The results show 2.64%dBR gain for coded views and 0.64% gain for synthesized views.

Multiview video plus depth (MVD) has proved to be a promising format enabling various 3D applications. One approach to achieve better MVD compression is to adjust the spatial resolution of depth map based on the content and the application. In this research two schemes are considered: first, multiview video coding accompanied by depth maps to improve the texture coding performance. Second, multiview video plus depth (MVD) coding targeting highest quality for synthesized views. Two algorithms to select the best spatial resolution for each scheme are proposed and the results show 10.8% and 16.5% bitrate reduction compared to the anchor case where depth map resolution is fixed.

In this paper, we propose a content-adaptive pre-processing for downsampling depth map for 3D multiview plus depth video coding. The proposed scheme takes advantage of spatially varying content of depth maps and targets improved encoding performance. The key idea is to divide the video frames into several horizontal and vertical stripes and downsample each of them with an appropriate downsampling ratio. With this approach, the rectangular shape of the frames are preserved, hence the video sequence can be coded with a standard encoder. The downsampling ratios, defined for each Intra period, are determined via a Rate Distortion Optimization process. Simulation results show that the proposed method outperforms the reference in which no downsampling is used by 0.35dB of Bjontegaard delta Peak Signal-to-Noise Ratio (PSNR) and brings up to 31% and average of 18% of Bjontegaard delta bitrate reduction (dBR).

One approach for stereoscopic video compression is to down sample the content prior to encoding and up sample it to the original spatial resolution after decoding. In this study it is shown that the ratio by which the content should be rescaled is sequence dependent. Hence, a frequency based method is introduced enabling fast and accurate estimation of the best down sampling ratio for different stereoscopic video clips. It is shown that exploiting this approach can bring 3.38% delta bitrate reduction over five camera-captured sequences.

To meet the requirement of current bandwidth and storage facilities, it is required to further decrease the bitrate of 3D video content. This paper presents a scheme to partially filter different regions of the texture views and depth maps taking into account the characteristics of both of them. A combination of the distance of objects from the cameras and the spatial details of texture within the objects defines the location and strength of the smoothing filter that should be applied to that image. A series of subjective tests was conducted to confirm that the perceived quality of the filtered content remains intact and no quality degradations is introduced by the filtering steps. Finally, objective measurements show a Bjontegaard delta bitrate reduction up to 23.77% with an average of 15.2%.

The emerging MVC+D standard specifies the coding of Multiview Video plus Depth (MVD) data for enabling advanced 3D video applications. MVC+D specifications define the coding of all views of MVD at equal spatial resolution and apply a conventional MVC technique for coding the multiview texture and the depth independently. This paper presents a modified MVC+D coding scheme, where only the base view is coded at the original resolution whereas dependent views are coded at reduced resolution. To enable inter-view prediction, the base view is downsampled within the MVC coding loop to provide a relevant reference for dependent views. At the decoder side, the proposed scheme consists of a post-processing scheme which upsamples of the decoded views to their original resolution. The proposed scheme is compared against the original MVC+D scheme and an average of 4% delta bitrate reduction (dBR) in the coded views and 14.5% of dBR in the synthesized views are reported.

Depth-enhanced 3-D video coding includes coding of texture views and associated depth maps. It has been observed that coding of depth map at reduced resolution provides better rate-distortion performance on synthesized views comparing to utilization of full resolution (FR) depth maps in many coding scenarios based on the Advanced Video Coding (H.264/AVC) standard. Conventional techniques for down and upsampling do not take typical characteristics of depth maps, such as distinct edges and smooth regions within depth objects, into account. Hence, more efficient down and upsampling tools, capable of preserving edges better, are needed. In this letter, novel non-linear methods to down and upsample depth maps are presented. Bitrate comparison of synthesized views, including texture and depth map bitstreams, is presented against a conventional linear resampling algorithm. Objective results show an average bitrate reduction of 5.29% and 3.31% for the proposed down and upsampling methods with ratio ½, respectively, comparing to the anchor method. Moreover, a joint utilization of the proposed down and upsampling brings up to 20% and on average 7.35% bitrate reduction.

This paper presents a multiview-video-plus-depth coding scheme, which is compatible with the advanced video coding (H.264/AVC) standard and its multiview video coding (MVC) extension. This scheme introduces several encoding and in-loop coding tools for depth and texture video coding, such as depth-based texture motion vector prediction, depth-range-based weighted prediction, joint inter-view depth filtering, and gradual view refresh. The presented coding scheme is submitted to the 3D video coding (3DV) call for proposals (CfP) of the Moving Picture Experts Group standardization committee. When measured with commonly used objective metrics against the MVC anchor, the proposed scheme provides an average bitrate reduction of 26% and 35% for the 3DV CfP test scenarios with two and three views, respectively. The observed bitrate reduction is similar according to an analysis of the results obtained for the subjective tests on the 3DV CfP submissions.

In this study, we applied a locally adaptive filtering in 3D DCT domain to 3 views as a preprocessing stage for encoding. Afterwards, these views were encoded and the decoded views were used by a Depth-Image-Based Rendering algorithm (DIBR) to produce virtual intermediate views. A stereopair at a suitable separation for viewing on a stereoscopic display was selected among the synthesized views. A large-scale subjective assessment of the selected synthesized stereopair was performed. A bitrate reduction of 9% on average and up to 21.8% was achieved with almost no penalties on subjective perceived quality.

Asymmetric stereoscopic video coding takes advantage of the binocular suppression of the human vision by representing one of the views with a lower quality. This paper describes a subjective quality test with asymmetric stereoscopic video. Different options for achieving compressed mixed-quality and mixed-resolution asymmetric stereo video were studied and compared to symmetric stereo video. The bitstreams for different coding arrangements were simulcast-coded according to the Advanced Video Coding (H.264/AVC) standard. The results showed that in most cases, resolution-asymmetric stereo video with the downsampling ratio of 1/2 along both coordinate axes provided similar quality as symmetric and quality-asymmetric full-resolution stereo video. These results were achieved under same bitrate constrain while the processing complexity decreased considerably. Moreover, in all test cases, the symmetric and mixed-quality full-resolution stereoscopic video bitstreams resulted in a similar quality at the same bitrates.