KEYWORDS: Video, Video coding, Computer programming, Video compression, Visualization, Distortion, Quantization, Semantic video, Detection and tracking algorithms, Scalable video coding
The MPEG-4 Fine Grained Scalability (FGS) profile aims at scalable layered video encoding, in order to ensure efficient
video streaming in networks with fluctuating bandwidths. In this paper, we propose a novel technique, termed as FMOEMR,
which delivers significantly improved rate distortion performance compared to existing MPEG-4 Base Layer
encoding techniques. The video frames are re-encoded at high resolution at semantically and visually important regions
of the video (termed as Features, Motion and Objects) that are defined using a mask (FMO-Mask) and at low resolution
in the remaining regions. The multiple-resolution re-rendering step is implemented such that further MPEG-4
compression leads to low bit rate Base Layer video encoding. The Features, Motion and Objects Encoded-Multi-
Resolution (FMOE-MR) scheme is an integrated approach that requires only encoder-side modifications, and is
transparent to the decoder. Further, since the FMOE-MR scheme incorporates "smart" video preprocessing, it requires
no change in existing MPEG-4 codecs. As a result, it is straightforward to use the proposed FMOE-MR scheme with any
existing MPEG codec, thus allowing great flexibility in implementation. In this paper, we have described, and
implemented, unsupervised and semi-supervised algorithms to create the FMO-Mask from a given video sequence, using
state-of-the-art computer vision algorithms.
KEYWORDS: Lithium, Internet, Systems modeling, Control systems, Modeling and simulation, Video, Software development, Inspection, Data modeling, Computer science
Peer-to-Peer(P2P) streaming has become a very popular technique to realize live media broadcast over the Internet. Most previous research of P2P streaming focuses on the delivery of a single media stream (called a channel). The widely deployed implementations, however, all concurrently offer multiple channels through their P2P networks. This paper investigates the overlay organization for multi-channel P2P streaming systems through modeling and simulations. In particular, this paper examines the potential collaborations among nodes across multiple channels. Our investigation shows that collaboration among nodes across different channels can improve the overall performance of the multi-channel P2P streaming system. However, the collaboration strategies need to be carefully selected. Simple collaboration strategies, such as treating collaborative nodes (those "borrowed" from other channels) the same as a channel's native nodes (those playing the channel), tend to have marginal or even negative effects on the whole system performance. This result is contrary to common impression - the larger population the better performance of P2P system - and we found that this is caused by the differences between P2P streaming and traditional P2P file-sharing systems. Furthermore, this paper proposes a set of simple strategies that controls the upload-download ratio of collaborative nodes. We showed that this set of strategies produces a much better collaboration result for multi-channel P2P streaming systems. Although only a preliminary study, we believe the results will promote further investigation on the topic of multi-channel P2P streaming.
KEYWORDS: Motion models, Distortion, Solid modeling, Data compression, Data modeling, Quantization, Matrices, Motion analysis, Computer programming, Personal digital assistants
Body Animation Parameters (BAPs) are used to animate MPEG-4 compliant virtual human-like characters. In order to stream BAPs in real time interactive environments, the BAPs are compressed for low bitrate representation using a standard MPEG-4 compression pipeline. However, the standard MPEG-4 compression is inefficient for streaming to power-constrained devices, since the streamed data requires extra power in terms of CPU cycles for decompression. In this paper, we have proposed and implemented an indexing technique for a BAP data stream, resulting in a compressed representation of the motion data. The resulting compressed representation of the BAPs is 1superior to the MPEG-4-based BAP compression in terms of both, required network throughput and power consumption at the client end to receive the compressed data stream and extract the original BAP data from the compressed representation. Although the resulting motion after de-compression at the client end is lossy, the motion distortion is minimized by intelligent use of the hierarchical structure of the skeletal avatar model. Consequently, the proposed indexing method is ideal for streaming of motion data to power- and network-constrained devices such as PDAs, Pocket PCs and Laptop PCs operating in battery mode and other devices in a mobile network environment.
TCP is the de-facto standard transport-layer protocol in the Internet. However, TCP is generally considered to be inappropriate for delay-sensitive applications such as multimedia. This paper proposes a novel receiver-centered TCP (TCP-RC), which is a TCP modification at the receiver that is intended for delay-sensitive applications. The basic principle behind TCP-RC is that it achieves low latency at the expense of reliability. In particular, TCP-RC forges lost packets, passing them on to an enabled application. This allows low-latency transmission for a class of applications that do not demand full reliability. Results obtained from emulated experiments show that over a range of loss rates and round-trip times, TCP-RC has a significantly smaller average- and worst-case per-packet delay than regular TCP.
Conference Committee Involvement (3)
Multimedia Computing and Networking 2009
19 January 2009 | San Jose, California, United States
Multimedia Computing and Networking 2008
30 January 2008 | San Jose, California, United States
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