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16
Language and Compiler Support for Stream Programs
, 2009
"... Stream programs represent an important class of high-performance computations. Defined by their regular processing of sequences of data, stream programs appear most commonly in the context of audio, video, and digital signal processing, though also in networking, encryption, and other areas. Stream ..."
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Cited by 28 (2 self)
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Stream programs represent an important class of high-performance computations. Defined by their regular processing of sequences of data, stream programs appear most commonly in the context of audio, video, and digital signal processing, though also in networking, encryption, and other areas. Stream programs can be naturally represented as a graph of independent actors that communicate explicitly over data channels. In this work we focus on programs where the input and output rates of actors are known at compile time, enabling aggressive transformations by the compiler; this model is known as synchronous dataflow. We develop a new programming language, StreamIt, that empowers both programmers and compiler writers to leverage the unique properties of the streaming domain. StreamIt offers several new abstractions, including hierarchical single-input single-output streams, composable primitives for data reordering, and a mechanism called teleport messaging that enables precise event handling
Survey of Compressed-Domain Features used in Audio-Visual Indexing and Analysis
"... In this paper, we attempt to provide a comprehensive and high-level review of audiovisual features that can be extracted from the standard compressed domains, such as MPEG-1 and MPEG-2. The paper is motivated by the myriad of active research works in extraction and application of compressed-domain f ..."
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Cited by 24 (0 self)
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In this paper, we attempt to provide a comprehensive and high-level review of audiovisual features that can be extracted from the standard compressed domains, such as MPEG-1 and MPEG-2. The paper is motivated by the myriad of active research works in extraction and application of compressed-domain features in various fields, such as indexing, filtering, and manipulation. Compressed domain approaches avoid expensive computation and memory requirements involved in decoding and/or re-encoding. Selected features are categorized into four groups -- spatial visual (e.g., color, texture, edge, shape), motion (e.g., motion field, trajectory), audio (e.g., energy, spectral features, pitch), and coding (e.g., bit rate, frame/block type). For each feature, we briefly discuss the extraction methods, computational complexity, potential effectiveness in applications, and possible limitations caused by compress-domain approaches. Finally, we briefly describe audio-visual features specified in the MPEG-7 standard and discuss the possibility of extracting them in the compressed domain.
The Dali Multimedia Software Library
, 1999
"... This paper presents a new approach for constructing libraries for building processing-intensive multimedia software. Such software is currently constructed either "from scratch" or by using high-level libraries. We have found that the second approach produces inefficient code, while the fi ..."
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Cited by 8 (1 self)
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This paper presents a new approach for constructing libraries for building processing-intensive multimedia software. Such software is currently constructed either "from scratch" or by using high-level libraries. We have found that the second approach produces inefficient code, while the first approach is time-consuming. We therefore designed and implemented Dal, a set of reusable, high-performance primitives and abstractions that are at an intermediate point in this design space. By decomposing common multimedia data types and operations into thin abstractions and primitives, programs written using Dal are shorter and more reusable then hand-tuned C code, yet achieve competitive performance. This paper describes the design and implementation of Dal.
Mapping Stream Programs into the Compressed Domain
, 2007
"... Mapping Stream Programs into the Compressed Domain Due to the high data rates involved in audio, video, and signal processing applications, it is imperative to compress the data to decrease the amount of storage used. Unfortunately, this implies that any program operating on the data needs to be wra ..."
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Cited by 3 (2 self)
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Mapping Stream Programs into the Compressed Domain Due to the high data rates involved in audio, video, and signal processing applications, it is imperative to compress the data to decrease the amount of storage used. Unfortunately, this implies that any program operating on the data needs to be wrapped by a decompression and re-compression stage. Re-compression can incur significant computational overhead, while decompression swamps the application with the original volume of data. In this paper, we present a program transformation that greatly accelerates the processing of compressible data. Given a program that operates on uncompressed data, we output an equivalent program that operates directly on the compressed format. Our transformation applies to stream programs, a restricted but useful class of applications with regular communication and computation patterns. Our formulation is based on LZ77, a lossless compression algorithm that is utilized by ZIP and fully encapsulates common formats such as Apple Animation, Microsoft RLE, and Targa. We implemented a simple subset of our techniques in the StreamIt compiler, which emits executable plugins for two popular video editing tools: MEncoder and Blender. For common operations such as color adjustment and video compositing, mapping into the compressed domain offers a speedup roughly proportional to the overall compression ratio. For our benchmark suite of 12 videos in Apple Animation format, speedups range from 1.1x to 471x, with a median of 15x. 1.
A fast algorithm for reconstructing motioncompensated blocks in compressed domain
- Journal of Visual Languages & Computing
, 1999
"... Many advanced video applications require processing compressed video signals. For compression systems using the discrete cosine transform (DCT) with motion compensation, we propose an algorithm with adaptive low-pass filtering (ALPF) to reconstruct blocks with motion vectors in the compressed domain ..."
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Cited by 2 (0 self)
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Many advanced video applications require processing compressed video signals. For compression systems using the discrete cosine transform (DCT) with motion compensation, we propose an algorithm with adaptive low-pass filtering (ALPF) to reconstruct blocks with motion vectors in the compressed domain. Compared with the previous work, this algorithm is faster and reduces blocky artifacts caused by quantization. � 1999 Academic Press
HDH Based Compressed Video Cut Detection
"... This paper presents a video cut detection algorithm using multi-level Hausdorff distance histograms (HDH). Hausdorff distance is obtained by comparing edge points of successive frames, wherein the edge information is extracted from compressed frames directly. The use of Hausdorff distance histogram ..."
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Cited by 1 (0 self)
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This paper presents a video cut detection algorithm using multi-level Hausdorff distance histograms (HDH). Hausdorff distance is obtained by comparing edge points of successive frames, wherein the edge information is extracted from compressed frames directly. The use of Hausdorff distance histogram instead of the comparison of entering/exiting edge pixel counts [9] makes the algorithm more robust to complicated camera shots. The extraction of edge information in compressed domain greatly escalates the cut detection process, which is critical for indexing of large amount of video materials in large scale video databases. The performance of this algorithm has been tested on a variety of videos. The experimental results show that this algorithm can robustly tolerate rapid changes in scene brightness as well as multiple object and camera motions.
Closed-Loop MPEG Video Rendering
- Proc. IEEE Conf. Multimedia Computing and Systems
, 1997
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Manipulating Lossless Video in the Compressed Domain
"... A compressed-domain transformation is one that operates directly on the compressed format, rather than requiring conversion to an uncompressed format prior to processing. Performing operations in the compressed domain offers large speedups, as it reduces the volume of data processed and avoids the o ..."
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Cited by 1 (0 self)
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A compressed-domain transformation is one that operates directly on the compressed format, rather than requiring conversion to an uncompressed format prior to processing. Performing operations in the compressed domain offers large speedups, as it reduces the volume of data processed and avoids the overhead of re-compression. While previous researchers have focused on compressed-domain techniques for lossy data formats, there are few techniques that apply to lossless formats. In this paper, we present a general technique for transforming lossless data as compressed with the slidingwindow Lempel Ziv algorithm (LZ77). We focus on applications in video editing, where our technique supports color adjustment, video compositing, and other operations directly on the Apple Animation format (a variant of LZ77). We implemented a subset of our technique as an automatic program transformation. Using the StreamIt language, users write a program to operate on uncompressed data, and our compiler transforms the program to operate on compressed data. Experiments show that the technique offers speedups roughly proportional to the compression factor. For our benchmark suite of 12 videos in Apple Animation format, speedups range from 1.1x to 471x, with a median of 15x.
Header for SPIE use The Dalí Multimedia Software Library
, 2016
"... This paper presents a new approach for constructing libraries for building processing-intensive multimedia software. Such software is currently constructed either by using high-level libraries or by writing it “from scratch ” using C. We have found that the first approach produces inefficient code, ..."
Abstract
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This paper presents a new approach for constructing libraries for building processing-intensive multimedia software. Such software is currently constructed either by using high-level libraries or by writing it “from scratch ” using C. We have found that the first approach produces inefficient code, while the second approach is time-consuming and produces complex code that is difficult to maintain or reuse. We therefore designed and implemented Dalí, a set of reusable, high-performance primitives and abstractions that are at an intermediate level of abstraction between C and conventional libraries. By decomposing common multimedia data types and operations into thin abstractions and primitives, programs written using Dalí achieve performance competitive with hand-tuned C code, but are shorter and more reusable. Furthermore, Dalí programs can employ optimizations that are difficult to exploit in C (because the code is so verbose) and impossible using conventional libraries (because the abstractions are too thick). We discuss the design of Dalí, show several example programs written using Dalí, and show that programs written in Dalí achieve performance competitive to hand-tuned C programs.
