Implementation And Performance Analysis Of 2-d Order 16 Integer Transforms in H.264/AVC and AVS-video for high definition video coding
Peringassery Krishnan, Madhu
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H.264/AVC and AVS-video are two video coding standards that have a wide range of applications ranging from high-end professional camera and editing systems to low-end mobile applications. They strive to achieve maximum compression efficiency without compromising the quality of video. To this end many coding tools are defined in them. Transform coding is one among them. Transform coding represents the signal/image (that is currently in time/spatial domain) in another domain (transform domain), where most of the energy in signal/image is concentrated in a fewer number of coefficients. Thus the insignificant coefficients can be discarded after transform coding to achieve compression. In images/videos the DCT-II (which represents a signal/image as the weighted sum of cosine functions with different frequencies) is primarily used for transform coding. H.264/AVC and AVS-video utilize integer approximations of the DCT-II (known as integer cosine transform) to reduce computational complexity by performing only fixed-point arithmetic operations and eliminates the mismatches between the forward and inverse transforms. The order (size) of the integer cosine transforms used is small (4 x 4 and 8 x 8). They achieve the best coding efficiency for standard definition and low-resolution videos. But, better coding efficiency can be achieved for high definition videos by using higher order (16 x 16 and 32 x 32) integer cosine transforms. As high definition videos are becoming more and more popular, it is imperative that sooner or later they will be integrated into the standards. For this purpose many higher order (16 x 16 and 32 x 32) integer cosine transforms have been proposed. But, a comparative study on the performance of these higher order integer cosine transforms in H.264/AVC and AVS-video has not been done yet. The purpose of the research is to analyze some higher order 16 x 16 integer cosine transforms, implement them in H.264/AVC and AVS-video and carry out a comparative study of their performances.