From 3417567558ed1e3cea8bf67f67d56d3c9c4002a9 Mon Sep 17 00:00:00 2001 From: Thomas Vander Stichele Date: Sun, 23 Dec 2001 20:21:20 +0000 Subject: more fixes Original commit message from CVS: more fixes --- gst-libs/gst/idct/floatidct.c | 102 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 102 insertions(+) create mode 100644 gst-libs/gst/idct/floatidct.c (limited to 'gst-libs/gst/idct/floatidct.c') diff --git a/gst-libs/gst/idct/floatidct.c b/gst-libs/gst/idct/floatidct.c new file mode 100644 index 00000000..520c3913 --- /dev/null +++ b/gst-libs/gst/idct/floatidct.c @@ -0,0 +1,102 @@ +/* Reference_IDCT.c, Inverse Discrete Fourier Transform, double precision */ + +/* Copyright (C) 1996, MPEG Software Simulation Group. All Rights Reserved. */ + +/* + * Disclaimer of Warranty + * + * These software programs are available to the user without any license fee or + * royalty on an "as is" basis. The MPEG Software Simulation Group disclaims + * any and all warranties, whether express, implied, or statuary, including any + * implied warranties or merchantability or of fitness for a particular + * purpose. In no event shall the copyright-holder be liable for any + * incidental, punitive, or consequential damages of any kind whatsoever + * arising from the use of these programs. + * + * This disclaimer of warranty extends to the user of these programs and user's + * customers, employees, agents, transferees, successors, and assigns. + * + * The MPEG Software Simulation Group does not represent or warrant that the + * programs furnished hereunder are free of infringement of any third-party + * patents. + * + * Commercial implementations of MPEG-1 and MPEG-2 video, including shareware, + * are subject to royalty fees to patent holders. Many of these patents are + * general enough such that they are unavoidable regardless of implementation + * design. + * + */ + +/* Perform IEEE 1180 reference (64-bit floating point, separable 8x1 + * direct matrix multiply) Inverse Discrete Cosine Transform +*/ + + +/* Here we use math.h to generate constants. Compiler results may + vary a little */ + +#include + +#ifndef PI +# ifdef M_PI +# define PI M_PI +# else +# define PI 3.14159265358979323846 +# endif +#endif + +/* private data */ + +/* cosine transform matrix for 8x1 IDCT */ +static double gst_idct_float_c[8][8]; + +/* initialize DCT coefficient matrix */ + +void gst_idct_init_float_idct() +{ + int freq, time; + double scale; + + for (freq=0; freq < 8; freq++) + { + scale = (freq == 0) ? sqrt(0.125) : 0.5; + for (time=0; time<8; time++) + gst_idct_float_c[freq][time] = scale*cos((PI/8.0)*freq*(time + 0.5)); + } +} + +/* perform IDCT matrix multiply for 8x8 coefficient block */ + +void gst_idct_float_idct(block) +short *block; +{ + int i, j, k, v; + double partial_product; + double tmp[64]; + + for (i=0; i<8; i++) + for (j=0; j<8; j++) + { + partial_product = 0.0; + + for (k=0; k<8; k++) + partial_product+= gst_idct_float_c[k][j]*block[8*i+k]; + + tmp[8*i+j] = partial_product; + } + + /* Transpose operation is integrated into address mapping by switching + loop order of i and j */ + + for (j=0; j<8; j++) + for (i=0; i<8; i++) + { + partial_product = 0.0; + + for (k=0; k<8; k++) + partial_product+= gst_idct_float_c[k][i]*tmp[8*k+j]; + + v = (int) floor(partial_product+0.5); + block[8*i+j] = (v<-256) ? -256 : ((v>255) ? 255 : v); + } +} -- cgit v1.2.1