Li-Ming Tseng

Harmonic broadcasting for video-on-demand service

Using conventional broadcasting, if we want to support a 120-minute popular movie every 10 minutes, we need 12 video channels. Assuming the set-top box at the client end can buffer portions of the playing video on a disk, pyramid broadcasting schemes can reduce the bandwidth requirements to 5.7 channels. We present a new scheme which only needs 3.2 channels. For a movie with length D minutes, if we want to reduce the viewer waiting time to D/N minutes, we only need to allocate H(N) video channels to broadcast the movie periodically, where H(N) is the harmonic number of N, H(N)=1+1/2+...+1/N. In order to support video-on-demand service for a popular movie, the new scheme greatly reduces the bandwidth requirements.

Staircase data broadcasting and receiving scheme for hot video service

For a 120-minute popular movie, with 4 video channels, current digital video broadcasting systems can support the movie every 30 minutes. Suppose the set-top box at client end can buffer portions of the playing video on disk. Pyramid broadcasting schemes can support the movie every 19 minutes. We present a new data broadcasting and receiving scheme, which can service the movie every 8 minutes. For a given bandwidth allocation, the new scheme greatly reduces the viewer waiting time. The disk space and transfer rate requirements of the set-top box are also reduced to be feasible.

Adaptive fast data broadcasting scheme for video-on-demand service

As we support video-on-demand (VOD) service with batching schemes, the bandwidth requirement will be very large for a popular movie. For a hot video, fast data broadcasting scheme substantially reduce the bandwidth requirements as compared with batching schemes. However, the fast data broadcasting scheme needs to predict which movie is hot. If the prediction is not accurate, the allocated bandwidth will be wasted. This paper presents a new data broadcasting scheme for VOD service. For a movie, as it is popular, the new scheme will work like the fast data broadcasting scheme to save the communication bandwidth. If there is no request for the movie, the new scheme will not allocate bandwidth for the movie. Therefore, the bandwidth allocation for a movie is always efficient whether or not the movie is popular.

A multimedia gateway for phone/fax and MIME mail

Facsimiles have become the most popular form of text communication on the public switched telephone network (PSTN). At the same time, the e-mail is the well-liked textual delivery system on computer networks. The message exchange between the fax/phone and e-mail will improve their availability and increase their messaging capabilities. In the Distributed System Laboratory at the National Central University, ROC, a new system integrating the MIME (multipurpose internet mail extensions) mail and fax/phone has been proposed and implemented to fulfil the requirements of bidirectional multimedia messaging. A user can send mails from Internet to PSTN. Furthermore, our system allows transmitting multimedia messages from PSTN to Internet. The system has the following properties: (1) only use the usual current equipments, e.g. telephones, G3 fax machines and personal computers, (2) be conformable to the popular protocols and existing systems, (3) provide user-friendly interfaces, such as the voice guided help, and (4) provide a universal and transparent addressing scheme between facsimiles and e-mail. Finally, we believe that our system meets real user needs.

Adaptive Live Broadcasting for Highly-Demand Videos

With the growth of broadband networks, Video-on-Demand (VoD) has become realistic. Many significant broadcasting schemes have been proposed to reduce the bandwidth requirements for stored popular videos, but they cannot be used to support live video broadcast perfectly. Herein, we propose a new broadcasting scheme, called the Adaptive Live Broadcasting (ALB) scheme, which supports live video broadcasting and performs well over a wide range of request arrival rates. From our analysis and comparison, we find that our ALB scheme is suitable for broadcasting live video. It has several significant advantages: (1) It has the shortest maximum waiting time with fixed channels. (2) It has the lowest maximum I/O transfer requirements with a fixed maximum waiting time at the client end. A simulation is employed to evaluate several live broadcasting schemes: UD, ST, AFB and ALB. The results reveal that our ALB scheme consumes the least server bandwidth.

An efficient scheme for broadcasting popular videos at low buffer demand

Data broadcasting is independent of arrivals of requests, and thus it is suitable to transmit popular videos that may interest many viewers at a particular period of time. One broadcasting method (called periodic broadcasting) is to divide a popular video into segments, which are then simultaneously broadcast on different data channels. Once clients want to watch the video, they download the segments from these channels. Specially, the greedy disk-conserving broadcasting (GDB) scheme supports a client with a small bandwidth. In comparison with other similar schemes such as the skyscraper broadcasting (SkB) and the client-centric approach (CCA) schemes, the GDB clients have smaller waiting time. Extending GDB, this work designs a reverse GDB (RGDB) scheme to achieve small buffering spaces as well as low bandwidths at the client. We further mathematically prove that RGDB still guarantees on-time video delivery at small client bandwidths. A formula is derived for the maximum number of segments buffered by an RGDB client. Finally, an analysis shows that RGDB has 33-50% smaller client buffer requirements than GDB in most situations.

Smooth Fast Broadcasting (SFB) for Compressed Videos

One way to broadcast a popular video is to partition the video into segments, which are broadcasted on several streams periodically. The approach lets multiple users share streams; thus, the stress on the scarce bandwidth can be alleviated without sacrificing viewers’ waiting time. One representative approach is the Fast Broadcasting (FB) scheme. The scheme does not obtain shortest waiting time but it can offer a more reliable video transmission on wireless networks. However, the scheme mainly supports transmission of CBR-encoded videos. In this paper, we propose a FB-based scheme for VBR-encoded videos. The scheme can smooth required bandwidth. From the simulation results, the SFB scheme has smaller required bandwidth, buffers, and disk transfer rate than the FB scheme. For a video, the maximum difference of its required bandwidth is less or equal to max(\(B^i_{max} - B^i_{min}\)), where \(B^i_{max}\) and \(B^i_{min}\) represent the maximum and minimum required bandwidth on stream i.

Interleaving harmonic broadcasting and receiving scheme with loss-anticipation delivery

With the growth of broadband networks, video-on-demand (VoD) has become realistic. Many significant broadcasting schemes have been proposed to reduce the bandwidth requirement for stored popular videos, but they cannot be used for provide reliable delivery over lossy channels perfectly. Herein, we propose a new broadcasting scheme, called the interleaving harmonic broadcasting (IHB) scheme, which guarantees continuous playback, and mitigates the effect of packet losses. Further, in comparison with the poly-harmonic broadcasting (PHB), cautions harmonic broadcasting (CHB) scheme, reliable periodic broadcasting (RPB) scheme and second chance broadcasting (SCB) scheme, the IHB outperforms on required bandwidth, maximum required buffers and maximum disk transfer rate.

A Seamless Broadcasting Scheme with Live Video Support

Broadcasting schemes, such as the fast broadcasting and harmonic broadcasting schemes, significantly reduce the bandwidth requirement of video-on-demand services. In the real world, some history events are very hot. For example, every year in March, thousands of people connect to Internet to watch the live show of Oscar Night. Such actions easily cause the networks contested. However, the schemes mentioned previously cannot alleviate the problem because they do not support live broadcasting. In this paper, we analyze the requirements for transferring live videos. Based on the requirements, a time skewing approach is proposed to enable the broadcasting schemes to support live broadcasting. However, the improved schemes require extra bandwidth for live broadcasting once the length of live shows exceeds the default. Accordingly, we proposed a scalable binomial broadcasting scheme to transfer live videos using constant bandwidth by increasing clients’ waiting time. When the scheme finds that the length of a video exceeds the default, it doubles the length of to-be-played segments and then its required bandwidth is constant.

Adaptive live broadcasting for highly-demanded videos

With the growth of broadband networks, the video-on-demand (VoD) becomes realistic. Many significant broadcasting schemes are proposed to reduce the bandwidth requirements for stored popular videos, but they cannot be used to support live video broadcast perfectly. Herein, we propose a new broadcasting scheme, called adaptive live broadcasting (ALB) scheme, which supports live video broadcasting and performs well over a wide range of request arrival rates. From our analysis and comparison, we find that our ALB scheme is suitable to broadcast live video. It has several significant advantages: (1) it has the shortest maximum waiting time with fixed channels; (2) it has the least maximum I/O transfer requirements with fixed maximum waiting time at client end. Finally, a simulation is employed to evaluate several live broadcasting schemes, such as UD, ST AFB and ALB. The results reveal our ALB scheme consumes the least server bandwidth.