Marco Folli

ILPS: a scalable multiple description coding scheme for H.264

The most recent literature indicates multiple description coding (MDC) as a promising coding approach to handle the problem of video transmission over unreliable networks with different quality and bandwidth constraints. In this work, we describe an approach that moves from the concept of spatial MDC and improves coding efficiency by exploiting some form of scalability. In the algorithm, we first generate four subsequences by sub-sampling, these subsequences are then taken in pairs that will form each of the two descriptions. For each description, one of the original subsequences is predicted from the other one via some scalable algorithms, focusing on the inter layer prediction scheme. The proposed algorithm has been implemented as pre- and post- processing of the standard H.264/SVC coder. The experimental results presented show that the algorithm provides excellent results in several conditions including 3D video sequences.

ILPS: A Scalable Multiple Description Coding Scheme for H.264

The most recent literature indicates multiple description coding (MDC) as a promising coding approach to handle the problem of video transmission over unreliable networks with different quality and bandwidth constraints. We introduce an approach moving from the concept of spatial MDC and introducing some algorithms to obtain sub-streams that are more efficient by exploiting some form of scalability. In the algorithm, we first generate four subsequences by sub-sampling, then two of these subsequences are jointly used to form each of the two descriptions. For each description, one of the original subsequences is predicted from the other one via some scalable algorithms, focusing on the inter layer prediction scheme. The proposed algorithm has been implemented as pre- and post- processing of the standard H.264/SVC coder. The experimental results are presented and we show it provides excellent results.

Improved Multicast Algorithm for Overlay Multicast in P2P Based Video Streaming

In this paper we introduce some significant improvements to a well known algorithm for multicast in overlay networks, namely ZigZag. The improvements are mainly related to a better handling of peer churn, avoiding service interruption to the subtree rooted at the departed node. Since the target is a video streaming service, additional constraints are related to a minimum serving quality for outgoing links. This translates in a maximum number of children for each node depending on its outgoing link capacity: to allow this, more realistic constraints on node heterogeneity are introduced so that the multicast tree is allowed to grow unbalanced. It is also shown that exploiting the overlapped control structure with scalable coded video it is possible to minimize service interruptions due to peers departure while minimizing signaling overhead. The changes have been implemented and validated using network simulator 2 to show the effectiveness of the procedures.

Quality modeling for the medium grain scalability option of H.264/SVC

Rate vs. quality is a crucial trade off not only for efficient video coding and transmission but also for adaptive transmission strategies in wireless networks and/or congestion-prone networks. Scalable coders are well suited to tackle the time-varying capacities of these environments. In this paper we propose a semi-analytical model suitable for the medium grain scalable option of the H.264 standard and discuss the parameters influencing its performance. Results show it can effectively be used to represent the expected rate for different quality layers and thus its applicability to algorithms for resource optimization.

Multiple description coding algorithms for H.264 coder

In this paper we address the problem of video transmission over unreliable networks. The proposed approach moves from the concept of multiple description coding (MDC) introducing some simple algorithms to obtain sub-streams introducing the concepts of either spatial, temporal, SNR adaptation. The proposed algorithms have been implemented as pre- post- processing of the basic H.264/SVC codec. Although in principle as many descriptions as desired can be generated, simulation results using only two description show good results both when all descriptions are received and when only one of the two is received. Analysis performed in case of either random or packet losses show the robustness of the algorithms.

Streaming of H.264 video using scalable multiple descriptions and rateless codes

Efficient and reliable techniques are key factors in the delivery of multimedia information over networks such as mobile ad hoc networks and the internet. Existing works tend to mix source coding techniques like multiple description coding and scalability with network techniques such as path diversity and forward error correction capabilities (FEC) or more recently rateless codes. In this work we exploit all these factors and propose a technique that generates H.264 compatible scalable streams which are sent over independent paths using rateless codes. The amount of allowed redundancy is adapted according to the channel capacity on a group of pictures basis. We show that the approach is efficient and allows to derive some design criteria to determine coding rate and buffer size at the receiver.

Design of a service platform for delay-sensitive video streaming applications based on multicast p2p and scalable MDC encoding

The great diffusion of Internet accesses in the world and the enormous evolution of the Internet technologies have strongly determined dissemination and consolidation of many applications of video content distribution. However, multicast real-time video communications for interactive service applications with a very high number of users, like for example multipoint videoconferences and interactive video games, remains a challenging research topic for the presence of very strict requirements in terms of end-to-end delay and perceived quality. The target of this paper is to propose a video distribution platform that is able to provide a huge number of users with a delay constrained multicast video streaming. To this purpose, the proposed content delivery platform is based on a peer-to-peer approach that exploits multicast overlay organization of the peers to address the challenges due to bandwidth heterogeneity. To improve reliability and flexibility, video is coded using a scalable multiple description approach. Some design guidelines are provided taking into account some requirements in terms of delay, average PSNR, robustness against underlying network bandwidth fluctuations, and fairness.

Parameters optimization for a scalable multiple description coding scheme based on spatial subsampling

In this work, we design a multiple description coding (MDC) system for video streams moving from the concept of spatial MDC and introducing an efficient algorithm to obtain substreams that exploits some form of scalability. We first generate four subsequences by sub-sampling, then, from these four subsequences, by jointly coding two of them, we generate two descriptions. Finally, each description is compressed independently with the recent H.264/SVC video coding standard. In order to achieve some sort of scalability, for each description, we predict one of the original subsequences from the other one via inter layer prediction, thus generating a base layer, containing one subsequence, and an enhancement layer, containing the other one. In this paper, we present some results, varying the fraction of the total rate assigned to the base layer, in order to find the better value that guarantees the optimal performances in case not all the (sub)streams are received.

A Scalable Multiple Description Scheme for 3D Video Coding Based on the Interlayer Prediction Structure

The most recent literature indicates multiple description coding (MDC) as a promising coding approach to handle the problem of video transmission over unreliable networks with different quality and bandwidth constraints. Furthermore, following recent commercial availability of autostereoscopic 3D displays that allow 3D visual data to be viewed without the use of special headgear or glasses, it is anticipated that the applications of 3D video will increase rapidly in the near future. Moving from the concept of spatial MDC, in this paper we introduce some efficient algorithms to obtain 3D substreams that also exploit some form of scalability. These algorithms are then applied to both coded stereo sequences and to depth image-based rendering (DIBR). In these algorithms, we first generate four 3D subsequences by subsampling, and then two of these subsequences are jointly used to form each of the two descriptions. For each description, one of the original subsequences is predicted from the other one via some scalable algorithms, focusing on the inter layer prediction scheme. The proposed algorithms can be implemented as pre- and postprocessing of the standard H.264/SVC coder that remains fully compatible with any standard coder. The experimental results presented show that these algorithms provide excellent results.