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idct8x8_fixed

Constants

  • p : Int32Array

Used internally for transformation

Functions

Decode 8x8 block quantized DCT coefficients and inverse DCT transform. This is a fixed-point implementation of the IDCT algorithm.

This IDCT algorithm is taken from: Y. A. Reznik, A. T. Hinds, L. Yu, Z. Ni, and C-X. Zhang, "Efficient fixed-point approximations of the 8x8 inverse discrete cosine transform" (invited paper), Proc. SPIE Vol. 6696, Sep. 24, 2007.

which is based on: Christoph Loeffler, Adriaan Ligtenberg, George S. Moschytz, "Practical Fast 1-D DCT Algorithms with 11 Multiplications", IEEE Intl. Conf. on Acoustics, Speech & Signal Processing, 1989, 988-991.

The stage numbers mentioned in the comments refer to Figure 1 in the Loeffler paper.

p : Int32Array

Used internally for transformation

Kind: global constant

idct8x8_fixed(qt, zz, dataOut)

Decode 8x8 block quantized DCT coefficients and inverse DCT transform. This is a fixed-point implementation of the IDCT algorithm.

This IDCT algorithm is taken from: Y. A. Reznik, A. T. Hinds, L. Yu, Z. Ni, and C-X. Zhang, "Efficient fixed-point approximations of the 8x8 inverse discrete cosine transform" (invited paper), Proc. SPIE Vol. 6696, Sep. 24, 2007.

which is based on: Christoph Loeffler, Adriaan Ligtenberg, George S. Moschytz, "Practical Fast 1-D DCT Algorithms with 11 Multiplications", IEEE Intl. Conf. on Acoustics, Speech & Signal Processing, 1989, 988-991.

The stage numbers mentioned in the comments refer to Figure 1 in the Loeffler paper.

Kind: global function

ParamTypeDescription
qtInt32Arrayquantization table
zzInt32Arrayzigzag-ordered coefficients
dataOutUint8Array | Uint8ClampedArray