عنوان البحث(Papers / Research Title)
Video Clip Image Compression Using DCT Technique
الناشر \ المحرر \ الكاتب (Author / Editor / Publisher)
توفيق عبد الخالق عباس الاسدي
Citation Information
توفيق,عبد,الخالق,عباس,الاسدي ,Video Clip Image Compression Using DCT Technique , Time 5/22/2011 6:02:46 AM : كلية تكنولوجيا المعلومات
وصف الابستركت (Abstract)
Video Clip Image Compression Using DCT Technique
الوصف الكامل (Full Abstract)
Wafaa Hassan AL-Marsomi Department of Computer Science , University of Babylon, Iraq
This paper presents a system for video compression which can be summarized into four stages the first stage is opening Audio/ Video Interleaved file (AVI) Video file. second stage is to compress sequence of video frames by using hybrid techniques presented in lossy compression in video codec through used of transform technique which is presented by discrete cosine transform (DCT) to reduce spatial redundancy in image data itself and to reduce temporal redundancy by using motion compensation technique which is employed associated with DCT to get error image produced by motion technique based on skew measurement and at last of this stage we used efficient method to code them, the third stage we inverse all hybrid compression techniques to obtain the decompressed sequence image of video file. At the fourth stage which is used to reconstruct video file AVI type .The proposed system achieves compression ratio close to the best known video compression techniques MPEG between (1:20- 1:40). This paper consist of five sections, in section 1 explain the introduction to video compression , in section 2 introduce to structure of AVI movie file , in section 3 explain the video codec (the proposed system), in section 4 display the experimental results with PSNR measurement, in section 5 display the conclusion .
Introduction:
Digital video has become very important form of information technology and is now used in many different areas, such as board casting, teleconferencing, mobile telephone, surveillance, and entertainment. People now expect to be able to access video through a wide range of different devices and over various networks. To provide these kinds of services we must know what is video compression for storage and transmission(K.Holtz).Compression of video imagery has become a necessity and very important because of transmission and storage of uncompressed video would be extremely costly and impractical. For instance, a video sequence running for (90) minutes, at (25) frames per second, at standard resolution of (720 *576), and with (24) bit per pixel would require (1343692800000) bit or approximately 156.43 gigabytes”. This is not a problem if we only wish to access and deal with video through high - end systems with a lot of storage and network band width. However, since it is desired that video will be accessible from a wide range of devices having different capabilities and connected to different networks, therefore some form compression for digital video is required (B. Tower ,2001). Compression refers to the process of reducing the number of bits required to represent the image and video comes in two forms lossless and lossy (N. Schaab ,2004). The lossless compression is a process to reduce image or video data for storage and transmission while retaining the quality of original image (i.e. the decoded image quality is required to be identical to image quality prior encoding. In lossy compression, on the other hand, some information present in the original image or video is discarded so that the original raw representation of image or video can only be approximately reconstructed from the compressed representation with high compression ratio. For more compression can be achieved with approximate quality to source image lossy compression is almost usually used than lossless compression to compress digital video (L. Kizewsk ,2004). In generall, in video compression the video sequences contain significant amount of statistical and subjective redundancy within and between frames. The ultimate goal of video source coding is the bit-rate reduction for storage and transmission by exploring both spatial and temporal redundancy and to encode “minimum set” of information using entropy coding techniques .This is usually results in compression of coded video data compared to original source data (T.sikora ,1998). These statistical and subjective redundancy that can be exploited for compression are called spatial and temporal redundancy. The performance of the video compression techniques depends on the amount of spatial and temporal redundancy contained in video data as well as on actual compression techniques used for encoding – with practical code schemes a trade – off between coding performance (high compression with sufficient quality ) and implementation complexity is targeted – thus one of the most method which is used for exploiting spatial redundancy is the transform coding and for exploiting temporal redundancy used motion estimation methods (T.sikora ,1998), all of these methods used in video codec which explain in figure (1) (P. Lindmark , 2005).
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