Storage and transport of six degrees of freedom (6DoF) dynamic volumetric visual content for immersive applications requires efficient compression. ISO/IEC MPEG has recently been working on a standard that aims to efficiently code and deliver 6DoF immersive visual experiences. This standard is called the MIV. MIV uses regular 2D video codecs to code the visual data. MPEG jointly with ITU-T VCEG, has also specified the VVC standard. VVC introduced recently the concept of subpicture. This tool was specifically designed to provide independent accessibility and decodability of sub-bitstreams for omnidirectional applications. This paper shows the benefit of using subpictures in the MIV use-case. While different ways in which subpictures could be used in MIV are discussed, a particular case study is selected. Namely, subpictures are used for parallel encoding and to reduce the number of decoder instances. Experimental results show that the cost of using subpictures in terms of bitrate overhead is negligible (0.1% to 0.4%), when compared to the overall bitrate. The number of decoder instances on the other hand decreases by a factor of two.

This article introduces the ISO/IEC MPEG Immersive Video (MIV) standard, MPEG-I Part 12, which is undergoing standardization. The draft MIV standard provides support for viewing immersive volumetric content captured by multiple cameras with six degrees of freedom (6DoF) within a viewing space that is determined by the camera arrangement in the capture rig. The bitstream format and decoding processes of the draft specification along with aspects of the Test Model for Immersive Video (TMIV) reference software encoder, decoder, and renderer are described. The use cases, test conditions, quality assessment methods, and experimental results are provided. In the TMIV, multiple texture and geometry views are coded as atlases of patches using a legacy 2-D video codec, while optimizing for bitrate, pixel rate, and quality. The design of the bitstream format and decoder is based on the visual volumetric video-based coding (V3C) and video-based point cloud compression (V-PCC) standard, MPEG-I Part 5.

Surface light-field (SLF) is a mapping of a set of color vectors to a set of ray vectors that originate at a point on a surface. It enables rendering photo-realistic view points in extended reality applications. However, the amount of data required to represent SLF is significantly more. Therefore, storing and distributing SLFs requires an efficient compressed representation. The Motion Pictures Experts Group (MPEG) has an on-going standard activity for the compression of point clouds. Until recently, this activity was targeting compression of single texture information, but is now investigating view dependent textures. In this paper, we propose methods to optimize coding of view dependent color without compromising on the visual quality. Our results show the optimizations provided in this paper reduce coded HEVC bit rate by 64% for the all-intra configuration and 52% for the random-access configuration, when compared to coding all texture independently.

The High Efficiency Video Coding (HEVC) standard includes support for a large range of image representation formats and provides an excellent image compression capability. The High Efficiency Image File Format (HEIF) offers a convenient way to encapsulate HEVC coded images, image sequences and animations together with associated metadata into a single file. This paper discusses various features and functionalities of the HEIF file format and compares the compression efficiency of HEVC still image coding to that of JPEG 2000. According to the experimental results HEVC provides about 25% bitrate reduction compared to JPEG 2000, while keeping the same objective picture quality.

This paper proposes to use RTP (Real-time Transport Protocol) Reception Hint Tracks for convenient recording and playback of a video call in MP4 format. The feasibility of RTP Reception Hint Tracks is validated as a part of an implemented end-to-end video call system. The proposed approach records a bidirectional Linphone video call and multiplexes it as MP4 RTP Reception Hint Tracks with the L-SMASH software library. It also stores RTCP (RTP Control Protocol) Reception Hint Tracks for additional timing information. Playback of the MP4 file is performed with VLC Media Player that is made compatible with RTP Reception Hint Tracks. The proposed proof-of-concept setup meets particularly well the needs of multi-codec solutions where different audio and video codecs can be used for a video call recording and playback. According to our analysis, recording RTP reception Hint Tracks increases the Linphone CPU time by under 1% and the bitrate by under 2% over the bare bitrate of the recorded RTP packets.

Virtual reality (VR) provides unprecedented immersive experience using high-resolution spherical stereoscopic panoramic video. Such an experience is achieved by using head-mounted display (HMD) which has very strict latency bounds in order to respond promptly to user movements. Conventional streaming of VR video requires large bandwidth because the entire captured panorama is transmitted. However, only a limited field-of-view (FOV) is displayed by an HMD, resulting in wastage of bandwidth. To alleviate the problem, this paper proposes a High Efficiency Video Coding (HEVC) compliant approach for efficient coding and streaming of stereoscopic VR content. The proposed method is based on partitioning video pictures into tiles, where only the required tiles corresponding to the primary viewport are transmitted in high resolution, while the remaining parts are transmitted in low resolution. Furthermore, this method enables coding stereoscopic video contents using a conventional HEVC codec, while still achieving significant compression gain by means of adopting inter-view prediction only in intra random access point (IRAP) pictures. Using this method, the predicted view can be decoded independently of the main view, hence allowing simultaneous decoding instances. Experimental results demonstrate that the proposed approach is able to substantially improve compression efficiency and streaming bitrate performance.

As in many digital telecommunications systems, the received data streams over Digital Video Broadcasting for Handhelds (DVB-H) may contain bursty transmission errors. The bursty error characteristics affect the end users' perceived audiovisual quality. This study examined the perceived unacceptability of instantaneous but noticeable audio, visual and audiovisual errors. The erroneous streams were generated from four popular television contents by applying three simulated error patterns with different error rates (1.7%, 6.9%, 13.8%) and error burst durations. Instantaneous unacceptability of errors was evaluated by 30 participants with simplified continuous assessment while watching the program content. The results show that with the two lowest error rates the audio errors were more unacceptable than video errors and with the highest error rate the visual and audiovisual errors become the most unacceptable.

A novel video splicing method is proposed which minimizes the tune-in time of mobile TV in Digital Video Broadcasting for Handheld terminals (DVB-H). DVB-H uses a time-sliced transmission scheme to reduce the power consumption used for radio reception. Tune-in time in DVB-H refers to the time between the start of the reception of a broadcast signal and the start of the media rendering. One of the significant factors in tune-in time is the time from the start of media decoding to the start of correct output from decoder, which can be minimized when a time-slice is started with a random access point picture such as an independent decoding refresh (IDR) picture in H.264/AVC. In IP datacasting (IPDC) over DVB-H, the encapsulation to time-slices is performed independently from encoding in a network element called IP encapsulator. At the time encoding, time-slice boundaries are not known exactly, and it is impossible to govern the location of IDR pictures relative to time-slice boundaries. It is proposed that an additional stream consisting of IDR pictures only is transmitted to the IP encapsulator, which replaces pictures in a normal bitstream with IDR pictures according to time-slice boundaries in order to achieve the minimum tune-in time. It has to be ensured that the "spliced" stream resulting from the operation of the IP encapsulator complies with the Hypothetical Reference Decoder (HRD) specification of H.264/AVC.

This paper introduces a method for unequal error protection (UEP) of media data in a time-sliced DVB-H channel. Media datagrams are assigned priorities using some a-priori knowledge. Datagrams covering a certain period of playback time are first grouped based on the priority assignment. Each group is then protected using Reed-Solomon forward error correction (FEC) codes and packed into multi-protocol encapsulation (MPE) FEC frames as defined by the DVB-H standard. All MPE-FEC frames for a certain period of playback time are then sent back to back without any delay between these MPE-FEC frames. This method of UEP is generic and can be tuned according to the priority assignment algorithm. Simulations using H.264/AVC video were conducted to evaluate the performance of the proposed method. It used a simple priority assignment algorithm. The resulting rate distortion graphs show good performance and an average luma peak signal-to-noise ratio (PSNR) improvement of up to 0.8 dB was achieved

This paper investigates the performance of H. 264/AVC video codec in a DVB-H (Handheld) datacasting environment. DVB-H was designed to provide point-to-multipoint (PTM) broadcast/multicast type transmission to handheld, battery operated devices. Reed-Solomon (RS) forward error correcting (FEC) codes are applied to Multi-Protocol Encapsulation (MPE) section payloads, termed MPE-FEC, to deliver data over DVB-H. The bitrate overheads incurred due to the additional FEC and packetization headers are analyzed. The requirement of additional data protection in the form of MPE-FEC is illustrated with the help of simulation results.