Developer Reference

  • 2021
  • 01/25/2021
  • Public Content
Contents

Discrete Cosine Transforms

Discrete Cosine Transform (DCT) of a real 2D image yields output results that are also real, which eliminates the need to use packed format for storing the transformed data. However, forward and inverse DCT functions
ippiDCTFwd
and
ippiDCTInv
need different context data structures to be initialized and filled in prior to their use. Consequently, the required workspace buffer size is different for these functions. In case of using an external buffer, its size must be determined by previously calling the respective support function. DCT functions that use context structures implement the modified computation algorithm proposed in [Rao90].
The DCT functions
ippiDCT8x8Fwd
and
ippiDCT8x8Inv
working on a fixed 8x8 image buffer need no context data or external workspace buffers. Functions
ippiDCT8x8Inv
meet IEEE-1180 standard requirements (see [IEEE]).
Intel IPP Discrete Cosine Transform functions working on a fixed 8x8 image buffer use Feig and Winograd algorithm ([Feig92]) modified for taking advantage of SIMD instructions. For details on algorithms used in DCT transforms and for more references, see [AP922].
Product and Performance Information
Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.
Notice revision #20201201

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.