Video Codec Optimizations on Cortex A8

Abstract

With the continuous enhancement in the speed and architecture of mobile processors it has become possible to play even high resolution videos on them. However the compilers have lagged behind in taking full utilization of the processing capabilities of the underlying hardware. H.264, known for its high compression ratio and computational complexity, needs performance optimizations for a computationally constraint environment. Some of these techniques are described in this paper.Index Terms-H.264 video decoder, Cortex Optimizations, cache optimizations.

A Novel Approach for Reduction of Huffman Cost Table in Image Compression

“…The binary Huffman coding [1,2,4,8,13] is the process of dividing the image into matrix of colour codes representing various colours and then it will calculate the probabilities of occurrences of each pixel, put them into descending order and then will append the binary digits to each probability/pixel in a systematic way such that no two or more pixels should have same binary code. After obtaining these values we can make two types of files.…”

“…After obtaining these values we can make two types of files. One representing compressed file and other is Huffman cost table [1,2,3,4] used to decode or the mapping table between the symbols in the source file and the related codes in the compressed image.…”

“…Therefore, how to save the algorithm's storage space and how to increase its compression ratio have always been concerned. The compressed image obtained by Huffman algorithm [4,6,7,9] consists of two parts, one is the compressed source file and the other is the file head (Huffman Table) used to decode or the mapping table between the symbols in the source file and the related codes in the compressed image. The nature of Huffman coding [2,4,8] algorithm decides the constancy of the source image's compression ratio, so the algorithm's compression ratio is directly related to the cost of Huffman table.…”

“…Therefore, how to save the algorithm's storage space and how to increase its compression ratio have always been concerned [1,[4][5][6]. The compressed file obtained by Huffman algorithm consists of two parts: one is the compressed source file and the other is the file head (Huffman Table) …”