S. F. Chang and D. G. Messerschmitt, "Manipulation and compositing of MC-DCT compressed video," IEEE J. Select. Areas Commun., vol. 13, no. 1, pp. 1--11, Jan. 1995.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....the data is already provided in the transform domain without prior zero padding, and therefore Matucci s scheme cannot be used. Another disadvantage of the above methods is that they are limited to symmetric or antisymmetric filters. The works of Lee and Lee [7] Chang and Messerschmitt [8], and Neri et al. 9] provide an alternative to the CMP approach. They propose to precompute the product of the operator matrices corresponding to inverse DCT, the convolution, and the DCT, and then to use the combined operator matrix directly in the DCT domain. The efficiency of this approach ....

S.-F. Chang and D. G. Messerschmitt, "Manipulation and compositing of MC-DCT compressed video," IEEE J. Selected Areas in Communications, Vol. 13, no. 1, pp. 1-11, January 1995.

....algorithms that operate directly on compressed representations, saving on the computational cost of decompression and lowering the overall size of the data which must be processed. This eliminates the time consuming decompression and often leads to computationally more e#cient algorithms [CM95] Consequently, this study explores the possibility of making use of features available in compressed video data and proposes several video processing techniques operating directly on compressed video data. Specifically, techniques of processing MPEG 1 and MPEG 2 compressed data are developed to ....

....macroblocks in a P or B picture can be either intra coded or motion compensated (MC) The DC values of an intra coded macroblock in a P picture can be similarly obtained as those in an I picture. Extraction of exact DC values for MC macroblocks in a P picture is given by Chang and Messerschmitt [CM95] and is computationally expensive. Here we describe an approximation method proposed by Meng et al. MJC95] An MC macroblock in a P picture has a motion vector and four blocks of DCT coded MC errors. The motion vector allows us to trace back the macroblock to its matching counterpart in the ....

S.F. Chang and D.G. Messerschmitt. Manipulation and compositing of MC--DCT compressed video. IEEE Journal on Selected Areas in Communications: Special Issue on Intelligent Signal Processing, 13:1--11, 1995.

....c 4 denote four adjacent 8 8 blocks in the spatial domain as shown in Figure 1(a) Consider replacing each 2 2 block (of each of the 8 8 blocks) by its average to get the downsampled 8 8 block c shown in Fig. 1. This downsampling operation can also be represented in matrix notation as follows [1, 2, 4]: c = h i c i g i (1) where the downsampling lters h i ; g i are given by: h 2 = g 1 6 7 5 ; h 4 = g 2 6 7 5 (2) where u 4 8 is de ned in Fig. 1(b) and o 4 8 is a 4 8 zero matrix. Now consider implementing the same operation directly in the DCT domain i.e. consider ....

....for Video Technology, vol. 11, no. 4, pp. 461 474, April 2001. c IEEE. for i = 1 to 4. Most previous approaches for downsampling in the compressed domain (say in the DCT domain) rely on the fact that the DCT, being a linear orthonormal transform, is distributive over matrix multiplication [1, 2, 4, 5]. Let T denote the 8 8 DCT operator matrix. Since TT = T T = I we have DCT(c) TcT DCT(h i )DCT(c i )DCT(g i ) 3) DCT(h i ) and DCT(g i ) for i= 1 to 4 can be precomputed. Hence given DCT(c i ) for i= 1 to 4, DCT(c) can be computed as matrix multiplication. However even though ....

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S.-F. Chang and D. G. Messerschmitt, \Manipulation and compositing of MC-DCT compressed video," IEEE Journal on Selected Areas in Communication, vol. 13, pp. 1-11, Jan. 1995.

....channel. The straightforward approach of decompressing, carrying out the downsampling in spatial domain and then recompressing involves unnecessary work and is computationally too intensive to be feasible in realtime on currently available workstations. Hence recently there has been much work [1, 2, 3] in carrying out downsampling as well as other operations on video sequences directly in the compressed domain without requiring decompression and recompression. 8x8 c1 8x8 c2 8x8 c3 8x8 c4 2 8x8 c Figure 1: Downsampling 4 consecutive blocks to get a single block. Most previous ....

....c3 8x8 c4 2 8x8 c Figure 1: Downsampling 4 consecutive blocks to get a single block. Most previous approaches for downsampling in the compressed domain (say in the DCT domain) rely on the fact that the DCT, being a linear orthonormal transform, is distributive over matrix multiplication [4, 1, 2]. Let c 1 ; c 2 ; c 3 ; c 4 denote four adjacent 8 8 blocks in the spatial domain as shown in Figure 1 then the downsampled 8 8 block c can be written as: c = P 4 i=1 h i c i g i where the downsampling lters h i ; g i are usually taken as h 1 = 6 6 6 6 6 6 6 6 6 6 :5 :5 0 0 0 0 0 ....

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S.-F. Chang and D. G. Messerschmitt, \Manipulation and compositing of MC-DCT compressed video," IEEE Journal on Selected Areas in Communication, vol. 13, pp. 1-11, Jan. 1995.

....users. The straightforward approach of decompressing, carrying out the downsampling in spatial domain and then recompressing involves unnecessary work and is computationally too intensive to be feasible in realtime on currently available workstations. Hence recently there has been much work [6, 7, 8] in carrying out downsampling as well as other operations on video sequences directly in the compressed domain without requiring decompression and recompression. Most previous approaches for downsampling in the compressed domain (say in the DCT domain) rely on the fact that the DCT, being a ....

....sequences directly in the compressed domain without requiring decompression and recompression. Most previous approaches for downsampling in the compressed domain (say in the DCT domain) rely on the fact that the DCT, being a linear orthonormal transform, is distributive over matrix multiplication [9, 6, 7]. Let c 1 ; c 2 ; c 3 ; c 4 denote four adjacent 8 8 c1 8x8 c2 8x8 c3 8x8 c4 2 8x8 c Figure 1: Downsampling 4 consecutive blocks to get a single block. blocks in the spatial domain as shown in Figure 1 then the downsampled 8 8 block c can be written as: c = P 4 i=1 h i c i g i ....

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S.-F. Chang and D. G. Messerschmitt, \Manipulation and compositing of MC-DCT compressed video," IEEE JSAC, vol. 13, pp. 1-11, Jan. 1995.

....for thresholding. This algorithm detects only cuts and uses only B frames and requires 2 parameters. Algorithm D Use of DC coefficient difference sequences [10] DC DCT coefficient values for I, P, and B frames are extracted (DC coefficient values for P and B frames are reconstructed as in [11]) These values are used to construct a DC frame sequence, where a DC frame is a frame consisting of the average intensities of 8x8 blocks of the original frames. Differences between these DC frames are then computed. Results are presented for two metrics: the sum of the absolute DC frame ....

S.F. Chang and D.G. Messerschmitt. Manipulation and Compositing of MC-DCT Compressed Video. IEEE Journal on Selected Areas in Communications: Special Issue on Intelligent Signal Processing, 13(1):1--11, 1995.

....requires decoding the video, storing the uncompressed video frames, and displaying them in reverse order. This processing requires high memory and computational capabilities in playback devices. A more efficient architecture is presented in [1, 2] where a compresseddomain processing algorithm [3, 4] is developed for processing the original compressed video stream into a new reversed compressed video stream. When a standard playback device decodes this reversed compressed video stream, the video frames are displayed in reverse order. The compresseddomain reverse play algorithm achieves ....

S.-F. Chang and D. Messerschmitt, "Manipulation and compositing of MC-DCT compressed video," IEEE Journal on Selected Areas in Communications, vol. 13, January 1995.

....An MPEG sequence consisting of all I frames, while least efficient from a compression viewpoint, is more robust to channel impairments in a video communication system. In addition, an I frame MPEG video stream facilitates many video editing operations, e.g. DCT domain image processing algorithms [4] can be applied to each frame of the sequence to achieve the same effect on the entire sequence. Temporal mode conversions can be used to accommodate particular rate robustness profiles or IPB prediction sequences. However, performing conversions between some sets of modes may require generating ....

S.-F. Chang and D. Messerschmitt, "Manipulation and compositing of MC-DCT compressed video," IEEE Journal on Selected Areas in Communications, vol. 13, January 1995.

....matrices corresponding to inverse DCT (IDCT) the convolution, and the DCT, and then to use the combined operator matrix directly in the DCT domain, where the contributions of neighboring DCT data blocks are incorporated similarly as in the overlap and add (OLA) method. Chang and Messerschmitt [6] proposed similar ideas by using the distributive property of the DCT with respect to matrix multiplication. A more thorough study of this approach, in combination with downsampling, has been carried out by Neri et al. 7] In this work, we adopt and further develop the second approach of ....

S.-F. Chang and D. G. Messerschmitt, "Manipulation and compositing of MC-DCT compressed video," IEEE J. Selected Areas in Communications, vol. 13, no. 1, pp. 1-11, January 1995.

....domain representation. The compressed domain processing methodology often leads to reduced computation complexity compared to the spatial domain approach since it replaces the JPEG decompression and compression tasks with lower complexity sub tasks such as huffman decoding and huffman encoding [2, 5, 6, 8]. In this paper, we describe efficient compressed domain algorithms for operations in D 4 , the dihedral group of symmetries of a square, including portrait landscape conversion. These operations are easy to transcribe from the pixel representation to the quantized Discrete Cosine Transform (DCT) ....

....a JpegBlock structure efficiently (linearly in N ) uses the following key observation: The array A remains the same, except that coefficients lying on the same cross diagonal are reversed in order. Let [Z] denote the transposed zig zag index for the original zig zag index Z . That is, 1] 2#[2] = 1#[3] 5#[4] 4#: Consider a situation when the zig zag coefficients numbered 1# 3# 6# 7# 10# 11# 14 are the only non zero coefficients. Then, the zig zag ordered coefficient indices after transposition will be [1]#[3]#[7]#[6]#[14]#[11]#[10] Thus, each group of coefficients lying on ....

Chang, S. F. and Messerschmitt, D. G. Manipulation and compositing of MC-DCT compressed video. IEEE JSAC Special Issue on Intelligent Signal Processing, 13(1):1--11, January 1995.

....is the Discrete Cosine Transform (DCT) In the transform domain, lots of coefficients are small and are often quantized to zeroes. To take advantage of this lower data rate in the transform domain, our prior work has studied techniques for manipulating image in the transform compressed domain [1,2,3]. Given transform coefficients (e.g. DCT coefficients) of the input images, we can calculate the transform coefficients of the desired output images without converting images back to the uncompressed spatial domain. The overall implementation cost can thus be greatly reduced. In particular, we ....

....operation can be done equivalently in both the spatial and the transform domains, i.e. 3) where stands for the correlation operation. This property is useful in image pattern matching based on the transform coefficients, although the boundary effect requires some special considerations [3]. 3. Linear Filtering and General Geometrical Transformation of Images Linear filtering can be used to model many useful manipulation functions such as scaling and smoothing. A convenient way to describe 2D separable linear filtering of images is via prematrix and post matrix multiplications. ....

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S.-F. Chang and D. G. Messerschmitt, "Manipulation and Compositing of MC-DCT Compressed Video," accepted for publication in IEEE Journal of Selected Areas in Communications, 1994.

....motivation for compressed domain processing is that the volume of data tends to be quite small in the compressed domain. Furthermore, by avoiding the process of decompression and compression, the computation complexity could be significantly reduced while the image fidelity is not compromised [1], 5] 6] 8] 7] and [10] Since the discrete cosing transform (DCT) is chosen in many compression standards such as JPEG [11] and MPEG [4] the compressed domain that most of the methods deal with is the DCT domain. DCT is just one way of transforming the data in spatial domain to a ....

....lies in whether we can perform the pixel multiplication operation in the compressed domain. To accomplish this task, we reverse the Kar and Rao [2] approach to replace a spatial domain pixel multiplication with DCT domain convolution. This has been shown possible by Chang and Messerschmitt [1] and Smith and Lowe [10] However, the ability to perform convolution in DCT domain is of no use if we can not show the advantages of replacing a simpler element to element multiplication process with a more complex convolution process. Previous works only showed the ability of taking advantage of ....

S. -F. Chang and D. G. Messerschmitt, "Manipulation and Compositing of M C-DCT Compressed Video," IEEE JSAC Special Issue on Intelligent Signal Processing, vol. 13, no. 1, pp. 1-11, Jan. 1995.

....still requires the uncompressed mesh representation to be present in the memory. Finally, there exists a large body of research involving compression domain processing of di erent multimedia data types. This includes direct manipulation of compressed image [SS95, SR93] compressed video [AHC93, CM95] compressed text [ZM95, VC97] and compressed volume [LGK97, C 97] data. 22 5.2 Triangle Mesh Editing Operations In this subsection, we describe the set of editing operation that the proposed Compression Domain Mesh Editing (CDE) scheme supports. We believe they form a representative set ....

S.F. Chang and D. G. Messerschmitt. Manipulation and Compositing of MC-DCT Compressed Video. IEEE Journal on Selected Areas in Communications, 13, 1995.

No context found.

S. F. Chang and D. G. Messerschmitt, "Manipulation and compositing of MC-DCT compressed video," IEEE J. Select. Areas Commun., vol. 13, no. 1, pp. 1--11, Jan. 1995.

....All DCT coefficients, including the DC value, are readily available for I frames in MPEG video. For Pand B frames, however, only the residue error after motion compensation is DCT transformed and coded. To get the DCT coefficients in motion compensated frames, Chang and 12 Messershmidt [9] developed a compressed domain algorithm that computes DCT coefficients in translated blocks. This is based on the fact that the DCT is a linear transform. The algorithm becomes very efficient if only part of the DCT coefficients (e.g. the DC coefficient) is needed. Yeo and Liu [63] as well as ....

S.-F. Chang and D. G. Messerschmit, "Manipulation and compositing of MC-DCT compressed video", IEEE Journal on Selected Areas in Communications, Special Issue on Intelligent Signal Processing, Jan. 1995, pp. 1-11.

....extraction. All DCT coefficients, including the DC value, are readily available for I frames in MPEG video. For Pand B frames, however, only the residue error after motion compensation is DCT transformed and coded. To get the DCT coefficients in motion compensated frames, Chang and Messershmidt [9] developed a compressed domain algorithm that computes DCT coefficients in translated blocks. This is based on the fact that the DCT is a linear transform. The algorithm becomes very efficient if only part of the DCT coefficients (e.g. the DC coefficient) is needed. Yeo and Liu [63] as well as ....

S.-F. Chang and D. G. Messerschmit, "Manipulation and compositing of MC-DCT compressed video", IEEE Journal on Selected Areas in Communications, Special Issue on Intelligent Signal Processing, Jan. 1995, pp. 1-11.

....support architecture. It also uses unique CVEPS (Compressed Video Editing, Parsing, and Search) technologies described in [71] Other unique features of WebClip include compressed domain video editing, content based video retrieval, and multi resolution access. The compressed domain approach [14][10] 100] has great synergy with the network editing environment, in which compressed video sources are retrieved and edited to produce new video content, which is also represented in compressed form. Major components of WebClip are depicted in Figure 8. The video content aggregator collects video ....

S.-F. Chang and D.G. Messerschmitt, "Manipulation and Compositing of MC-DCT Compressed Video," IEEE Journal of Selected Areas in Communications, Special Issue on Intelligent Signal Processing, pp. 1-11, Jan. 1995.

No context found.

S.-F. Chang and D. G. Messerschmit, "Manipulation and compositing of MC-DCT compressed video", IEEE Journal on Selected Areas in Communications, Special Issue on Intelligent Signal Processing, Jan. 1995, pp. 1-11.

No context found.

S.F. Chang, D.G. Messerschmidt,"Manipulation and compositing of MC-DCT compressed video", IEEE J. Select. Areas Commun., 13 (1), Jan. 1995

No context found.

S. -F Chang and D. G. Messerschmitt, " Manipulation and Compositing of MC-DCT Compressed Video," IEEE Journal on Selected areas in Communications, vol. 13, no.1, Jan. 1995.

No context found.

S.-F. Chang and D. G. Messerschmitt, "Manipulation and compositing of MC-DCT compressed video," IEEE Journal Selected Areas in Communications, volume 13, no. 1, pp. 1--11, January 1995.

No context found.

S. -F Chang and D. G. Messerschmitt, " Manipulation and Compositing of MC-DCT Compressed Video," IEEE Journal on Selected areas in Communications. vol. 13, no.1, Jan. 1995.

No context found.

S.-F. Chang, D. G. Messerschmitt, Manipulation and Compositing of MC-DCT Compressed Video, IEEE JSAC Special Issue on Intelligent Signal Processing, 1994.

No context found.

S.-F. Chang and D. G. Messerschmitt, "Manipulation and compositing of MC-DCT compressed video," IEEE J. Selected Areas in Communications, Vol. 13, no. 1, pp. 1-11, January 1995.

No context found.

S. -F. Chang and D. G. Messerschmitt, "Manipulation and Compositing of MC-DCT Compressed Video", IEEE JSAC Special Issue on Intelligent Signal Processing, 1994.

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