Yufeng Shan

University of California, Berkeley | UCB · Department of Electrical Engineering and Computer Sciences

Computational modeling of visual saliency has become an important research problem in recent years, with applications in video quality estimation, video compression, object tracking, retargeting, summarization, and so on. While most visual saliency models for dynamic scenes operate on raw video, several models have been developed for use with compr...

In this paper we present two compressed-domain features that are highly indicative of saliency in natural video. We demonstrate the potential of these two features to indicate saliency by comparing their statistics around human fixation points against their statistics at control points away from fixations. Then, using these features, we construct a...

Visual saliency has been shown to depend on the unpredictability of the visual stimulus given its surround. Various previous works have advocated the equivalence between stimulus saliency and uncompressibility. We propose a direct measure of this quantity, namely the number of bits required by an optimal video compressor to encode a given video pat...

In this paper we present two compressed-domain features that are highly indicative of saliency in natural video. Their potential to predict saliency is demonstrated by comparing their statistics around human fixation points in a number of videos against the control points selected randomly away from fixations. Using these features, we construct a s...

Visual saliency modeling is an increasingly important research problem. While most saliency models for dynamic scenes operate on raw video, several models have also been developed for compressed video. This paper compares the accuracy of nine such models on a common eye-tracking dataset. The results indicate that a reasonably accurate saliency esti...

In conventional HTTP-based adaptive streaming (HAS), a video source is encoded at multiple levels of constant bitrate representations, and a client makes its representation selections according to the measured network bandwidth. While greatly simplifying adaptation to the varying network conditions, this strategy is not the best for optimizing the...

In this paper, we present a two-stage forward error correction (FEC) scheme with an enhanced link-layer protocol especially for multimedia data transmission over wireless LANs. At the application layer, packet-level FEC (stage-one) is added across packets to correct packet losses due to congestion and route disruption. Bit-level FEC (stage-two) is...

In this paper, we investigate a fine-grain adaptive forward error correction (FGA-FEC) coding scheme for scalable video bitstreams. In our work, both the embedded source bitstream and the error-control codes are granularly adapted at block level in intermediate overlay nodes to satisfy heterogeneous users with both different video frame-rate/spatia...

In this paper, we investigate a distributed fine grain adaptive FEC (FGA-FEC) scheme for scalable video stream-ing to heterogeneous users over a congested multihop network, where we do FGA-FEC decode/recode at selected intermediate overlay nodes, and do FGA-FEC adaptation at remaining nodes. In order to reduce the overall computational burden, we p...

In this paper, we extend our proposed FGA-FEC coding scheme, a generalized MD-FEC method, to wireless networks. To protect the encoded scalable video bitstream over a lossy channel and facilitate content adaptation at intermediate nodes, we use product codes based on BCH/CRC codes as row codes and RS codes as column codes. We give a fast algorithm...

In a wireless LAN, the throughput is essentially important for multimedia applications due to their high bit rate requirement. In this paper, we propose two link layer error protection schemes that improve the effective throughout of wireless networks. Error control is applied to the packet header and packet payload separately. The network intermed...

Multimedia applications have different Quality of Service (QoS) requirements. In a multi-hop network, the throughput is essentially important for real-time applications due to their high bit rate requirement. In the wireless networks, error comes from fading, noise, or interference. Link layer error control will have impact on the end-to- end throu...

In this paper, we propose a joint source-network error control coding (JSNC) scheme which efficiently integrates scalable video coding, error control coding and overlay infrastructure to stream video to heterogeneous users. The distributed overlay nodes adapt both the video bitstream and error control coding based on both user requirements and avai...

Overlay networks offer promising capabilities for video streaming, due to their support for application-layer processing at the overlay forwarding nodes. In this paper, we focus on the problem of providing lightweight support at selected intermediate overlay forwarding nodes to achieve increased error resilience on a single overlay path for video s...

Real-time streaming media over wireless networks is a challenging proposition due to the characteristics of video data and wireless channels. In this paper, we propose a set of cross-layer techniques for adaptive real-time video streaming over wireless networks. The adaptation is done with respect to both channel and data. The proposed novel packet...

Overlay networks offer promising capabilities for video streaming, due to their support for application-layer processing at the overlay forwarding nodes. In this paper we propose a novel overlay multi-hop FEC (OM-FEC) scheme that provides FEC encoding/decoding capabilities at intermediate nodes in an overlay path. Based on the current network condi...

In this paper, we focus on the problem of providing lightweight support at selected intermediate overlay forwarding nodes to achieve increased error resilience on a single peer-based overlay path for point-to-point video streaming. We propose a novel "Overlay Multi-hop FEC" (OM- FEC) scheme that is flexible and considers the error characteristics o...

Peer-to-peer based multimedia delivery is becoming increasingly more important in today's networks. Using a peer-to-peer network to assist video streaming is a topic of considerable interest. In this paper, we propose a novel hybrid video downloading/streaming scheme (HDS) that efficiently integrates traditional client/server based video streaming...

Wireless multimedia delivery is becoming increasingly more important in today's networks. Unlike wired packet switched networks that suffer from congestion related loss and delay, the wireless networks have to deal with a time varying, error prone, physical channel that in many instances is also severely bandwidth constrained. As such, the solution...

In a multi-hop network, the throughput is essentially important for real-time applications due to their high bit rate requirement. We investigate the performance of multimedia applications in wireless networks and the impact of various error control protocols. In particular, we propose a two stage error control scheme that improves the effective th...