R. Balsree, Agness Thawani, S. Gopalan et al. · 2006
Multimedia services over wireless networks were made popular by the arrival of smart handhelds. These devices bring heterogeneity to the wireless networks and to the content creation as the content cannot be delivered in its original format due to the difference in the capabilities of these handhelds. An intermediate stage of processing like transcoding is carried out before delivering multimedia content. Under certain scenarios, it is required to convert the content attributes such as bit rate, frame rate, etc. while still retaining the content format to cater to devices with varying capabilities. We propose an algorithm that prioritizes frames taking into account inter frame similarity to perform frame dropping. The priority value based frame dropping in turn aids in delivering better quality video. Our frame priority assignment algorithm is based on uniform distribution of dropped frames to minimize jitter and maximizing the distance between two consecutive dropped frames.
Cited by 3
Wang Xing Guo, Zheng Wei Guo, Zahoor Ahmad · 2002
The MPEG-2 video compression standard is successfully adapted in the DVD and digital TV broadcast industries. The new MPEG-4 standard has much broader and ambitious perspective to support high and low bit-rate multimedia applications on existing and future networks. MPEG-4 aims to complement MPEG-2, not override it. Therefore, one can envisage that MPEG-2 and MPEG-4 will co-operate and coexist in a synergistic manner for a wide variety of application environments. This paper addresses the problem of transcoding MPEG-2 video content to MPEG-4 compliant video bitstream. The goal is to develop effective architectures and algorithms for efficient transcoding. We discuss two transcoding approaches: the pixel domain method and compression domain method. We discuss their details to facilitate their applications in different situations. We report simulations authenticate the performance of the proposed transcoding solutions.
Cited by 6
Marcelo Garcia Manzato, Rudinei Goularte · 2006
The video adaptation has been developed with the objective of enabling the access by devices with limitant characteristics. One way to adapt the video is the transcoding technique, which can be applied in a large range of applications. However, it is known that the transcoding process has a high computational cost, which it is thought to be the main generator of delay. In this paper we present a transcoding evaluation in live video adaptation. As a result, the measures obtained can help researchers and developers to choose the best adaptation mechanism or system architecture for their specific applications
Cited by 2
Xiaoyang Wang, Xiaodong Tu · 2009
An adapt flexible macroblock ordering strategy based on unequal protection scheme is presented for video transcoding. The key point of our scheme is selecting the important macroblocks which belong to a separate slice group under prior protection in transmission. The judgement of the importance of the macroblocks is based on the differences of the DCT coefficients of neighbouring subblocks in a macroblock which represent the texture change and the complexity of the macroblock content. The number of the important macroblocks can be controlled effectively in predetermined range. The other macroblocks judged as unimportant are classified into two slices ac cording to the edge match rule contributing to the efficiency of the error concealment in decoder. The adapt FMO scheme enhance error resilient capability and improve error concealment capability in decoder. Experiments shows that the proposed flexible macroblock ordering strategy improve the subjective quality and objective quality 2–3 dB than traditional FM O type such as interlaced type and dispersed type suggested by h.264 if one unimportant slice is corrupted.
Cited by 1
Johan Garcia, Anna Brunström · 2000
Cited by 3
Peng Yin, Anthony Vetro, Minghui Xia et al. · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2003
This paper addresses the problem of selecting a single transcoding method from multiple transcoding possibilities that satisfy a specified delivery constraint. We first discus the rate-distortion modeling of DCT coefficients. Then, we quantify the distortion of the video transcoding output by examining the rate-distortion relationship of the popular transcoding techniques, including requantization, spatial downsampling and temporal downsampling. The use of our model is illustrated in some typical applications.
Cited by 14
K. Viswanath, Jayanta Mukhopadhyay, Prabir Kumar Biswas · 2009
Transcoding enables the transformation of multimedia content to adapt to a diverse nature of client/user requirements. In this paper, we propose a technique for transcoding wavelet coefficients to block DCT coefficients in the transform domain. In the first step, the wavelet coefficients are transformed into upsampled block DCT coefficients. Subsequently these transformed coefficients are synthesized by filtering in the block DCT space. To reduce the transcoding complexity, we perform upsampling and filtering operations in a single combined step. The proposed transcoding approach restricts all operations of the synthesis process in the block DCT space. The proposed approach achieves the same quality of reconstruction (Except rounding errors in processing) as that of spatial domain technique with reduced complexity for a given wavelet synthesis filter bank.
Cited by 5
Aviral Agarwal, Martin O’Connor, David L. Mills · 1981
The first part of this RFC describes in detail the Dacom 450 data
compression algorithms and is an update and correction to an earlier
memorandum. The second part of this RFC describes briefly the Dacom
500 data compression algorithm as used by the INTELPOST electronic-
mail network under development by the US Postal Service and several
foreign administrators.
Cited by 2
Chau, Wing San · Rare & Special e-Zone (The Hong Kong University of Science and Technology) · 2005
Key Frame Selection is the process to select the most representative frames of a long video sequence based on a given set of rules. This research work presents a novel algorithm for selecting a set of representative frames in MPEG compressed video. We use luminance DCT DC value, macroblock type and motion vector information to determine the motion activity and visual content change in MPEG compressed video. The advantages of this algorithm are highly accurate video content description and efficient extraction of the required information in the MPEG compressed domain by low complexity inverse quantization and variable length decoding. A visual content based key frame selection is proposed. One of the advantages of this approach is that it does not depend on any predefined threshold or parameter. It gives a set of key frame based on an objective model of visual content flow. Another advantage is that the predefined number of key frame can be obtained by using the proposed algorithm. This research work also presents a novel metric and a reliable algorithm for scene change detection. The new frame difference metric measures motion and content change across the video by using the motion vector and macroblock information in the MPEG compressed domain. With this new metric, a reliable scene change detection algorithm is discussed. Experimental results reveal that our scene change detection algorithm can successfully reduce the false alarms caused by local frame motion activity and at the same time increase the recall by amplifying the acceptance probability of the reliable scene change candidate.
Cited by 0
Rita Cucchiara, Costantino Grana, Andrea Prati · 2002
In this work we present a transcoding framework and an object-based technique to adapt live and stored videos to the user bandwidth and resources capabilities.
Cited by 3
Bo Shen, Susie Wee · 2007
Cited by 0
Roya Choupani, Stephan Wong, Mehmet Tolun · 2008
Video streaming over the Internet has gained popularity during the recent years which is mainly the result of the introduction of video-conferencing and video-telephony. These in turn have made it possible to bring to life many applications such as transmitting video over the Internet and telephone lines, surveillance and monitoring, telemedicine (medical con-sultation and diagnosis at a distance), and computer based training and education. These applications need a large bandwidth which is not available in all cases. Many video encoding standards have been introduced to deal with video compression and transmission problems. In this study, we have discussed the main technical features of the most important video coding standards in a comparative approach. The appropriateness of these features is ap-plication and transmission environment dependant. Manipulating video stream features or video transcoding methods are discussed as well.
Cited by 0
Dongyu Liu, Songqing Chen, Bo Shen · 2006
The increase of aggregate Internet bandwidth and the rapid development of 3G wireless networks demand efficient delivery of multimedia objects to all types of wireless devices. To handle requests from wireless devices at runtime, the transcode-enabled caching proxy has been proposed and a lot of research has been conducted to study online transcoding. Since transcoding is a CPU-intensive task, the transcoded versions can be saved to reduce the CPU load for future requests. However, extensively caching all transcoded results can quickly exhaust cache space. Constrained by available CPU and storage, existing transcode-enabled caching schemes always selectively cache certain transcoded versions, expecting that many future requests can be served from the cache while leaving CPU cycles for online transcoding for other requests. But such schemes treat the transcoder as a black box, leaving little room for flexible control of joint resource management between CPU and
Cited by 0
2008
A problem with trying to create voice interfaces to existing HTML web pages is that most web pages are designed and optimized for graphical browsing. Our approach has been to consider voice interfaces to web information not as a replacement for desktop browsing using a graphical interface, but as a way to meet mobile users ' needs for specific information. Such an interaction can be more directed and focused in nature than openended browsing tasks. In order to create usable voice interfaces to web information, we have identified a set of information structures that are commonly found on web pages and explored how they can be presented and navigated by voice. We have codified these structures in an XML annotation language called VXPL that can be used to annotate existing HTML code to indicate where these information structures exist. VXPL is designed so that it can be used for manual or automatic annotation of HTML code. In addition, we have implemented an automated transcoder that converts VXPL into VoiceXML with increased support for navigation and usability of the resulting interface. 1.
Cited by 0
Rita Cucchiara, Costantino Grana, Andrea Prati · IRIS UNIMORE (University of Modena and Reggio Emilia) · 2002
In this paper we present transcoding techniques for a video server architecture that enables the user to access live video streams by using different devices with different capabilities. For live videos, annotation methods cannot be exploited. Instead we propose methods of on-the-fly transcoding that adapt the video content with respect to the user resources and the video semantic. Thus we propose an object-based transcoding with "classes of relevance"(for instance People, Face and Background). To compare the different strategies we propose a metric based on the Weighted Mean Square Error that allows the analysis of different application scenarios by means of a class-wise distortion measure. The obtained results show that the use of semantic can improve the bandwidth to distortion ratio significantly.
Cited by 24Open access
Ravin Sachdeva, Sumit Johar, Emiliano Piccinelli · 2007
This paper describes a transcoding algorithm able to transcode a compressed video bitstream into a WMV9 (VC1) compliant bitstream. A Closed-Loop Spatial Domain Transcoding approach, modeled on the Cascaded Pixel Domain Transcoder (CPDT) is presented here. It incorporates reusing of information obtained from the input bitstream. To enhance the performance of the transcoder, an approach for pipelining the encoder/decoder processes in the transcoder is proposed here. These modifications can be easily adapted to all the transcoders producing WMV9 as output, the input for whom may include video streams of type MPEG-2, MPEG-4 or H.264. As a proof of concept, the suggested approach has been applied to the case of MPEG-2 to VC1 transcoding. Extensive analysis has been performed and the ultimate gain in transcoding speed achieved for the presented approach compared with MPEG-2 to VC1 CPDT, is in the range of 3 to 7 times faster than CPDT.
Cited by 1
Bo Shen, Wai-Tian Tan, Frederic Huve · IEEE Multimedia · 2008
A transcoder with dynamic feedback addresses interactivity, packet loss, and client power constraints in mobile communication systems.
Cited by 25
Chia-Hao Kao, Andrea Migliorati, Alessandro Gnutti et al. · 2025
Cited by 0
Sze Wei Lee, Bok‐Min Goi, Grace C.-W. Ting · International Journal of Internet Technology and Secured Transactions · 2021
The H.264 standard is widely deployed for high-quality consumer video recording, storage and sharing applications such as Blu-ray DVD and streaming HD video on the internet including YouTube. In current times, since videos are easily shared live on social media and messaging mobile apps, users need the ability to determine the ownership of these videos against being illegally distributed without proper acknowledgements to the owners, and to take actions against those who spread false videos that trigger viral fake news. Robust watermarking schemes are popularly applied techniques to solve these problems. These types of schemes are required to achieve robustness against modification attacks on the embedded watermark. In this paper, we present the design of a new robust watermarking scheme for these purposes, namely that achieves robustness against common modification attacks aiming to change the watermarks embedded by the owner, and it is furthermore resilient to transcoding. The latter property ensures that the embedded watermark remains detectable despite having undergone the common video processing operation of transcoding.
Cited by 0
Johan Garcia · 2002
The evolution of computer communications and the Internet has led to the emergence of a large number of communication technologies with widely different capabilities and characteristics. While this multitude of technologies provides a wide array of possibilities it also creates a complex and heterogeneous environment for higher-layer communication protocols. Specific link technologies, as well as overall network heterogeneity, can hamper user-perceived performance or impede end-to-end throughput. In this thesis we examine two transport layer centered approaches to improve performance. The first approach addresses the decrease in user satisfaction that occurs when web waiting times become too long. Increased transport layer flexibility with regards to reliability, together with error-resilient image coding, is used to enable a new trade-off. The user is given the possibility to reduce waiting times, at the expense of image fidelity. An experimental examination of this new functionality is provided, with a focus on image-coding aspects. The results show that reduced waiting times can be achieved, and user studies indicate the usefulness of this new trade-off. The second approach concerns the throughput degradations that can occur as a consequence of link and transport layer interactions. An experimental evaluation of the GSM environment shows that when negative interactions do occur, they are coupled to large variability in link layer round-trip times rather than simply to poor radio conditions. Another type of interaction can occur for link layers which expose higher layers to residual bit errors. Residual bit errors create an ambiguity problem for congestion controlled transport layer protocols which cannot correctly determine the cause for a loss. This ambiguity leads to an unnecessary throughput degradation. To mitigate this degradation, loss differentiation and notification mechanisms are proposed and experimentally evaluated from both performance and fairness perspectives. The results show that considerable performance improvements can be realized. However, there are also fairness implications that need to be taken into account since the same mechanisms that improve performance may also lead to unfairness towards flows that do not employ loss differentiation.
Cited by 0