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/*
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* jfdctint.c |
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* |
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* This file is part of the Independent JPEG Group's software. |
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* |
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* The authors make NO WARRANTY or representation, either express or implied, |
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* with respect to this software, its quality, accuracy, merchantability, or |
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* fitness for a particular purpose. This software is provided "AS IS", and |
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* you, its user, assume the entire risk as to its quality and accuracy. |
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* |
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* This software is copyright (C) 1991-1996, Thomas G. Lane. |
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* All Rights Reserved except as specified below. |
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* |
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* Permission is hereby granted to use, copy, modify, and distribute this |
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* software (or portions thereof) for any purpose, without fee, subject to |
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* these conditions: |
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* (1) If any part of the source code for this software is distributed, then |
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* this README file must be included, with this copyright and no-warranty |
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* notice unaltered; and any additions, deletions, or changes to the original |
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* files must be clearly indicated in accompanying documentation. |
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* (2) If only executable code is distributed, then the accompanying |
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* documentation must state that "this software is based in part on the work |
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* of the Independent JPEG Group". |
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* (3) Permission for use of this software is granted only if the user accepts |
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* full responsibility for any undesirable consequences; the authors accept |
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* NO LIABILITY for damages of any kind. |
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* |
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* These conditions apply to any software derived from or based on the IJG |
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* code, not just to the unmodified library. If you use our work, you ought |
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* to acknowledge us. |
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* |
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* Permission is NOT granted for the use of any IJG author's name or company |
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* name in advertising or publicity relating to this software or products |
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* derived from it. This software may be referred to only as "the Independent |
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* JPEG Group's software". |
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* |
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* We specifically permit and encourage the use of this software as the basis |
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* of commercial products, provided that all warranty or liability claims are |
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* assumed by the product vendor. |
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* |
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* This file contains a slow-but-accurate integer implementation of the |
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* forward DCT (Discrete Cosine Transform). |
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* |
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* A 2-D DCT can be done by 1-D DCT on each row followed by 1-D DCT |
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* on each column. Direct algorithms are also available, but they are |
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* much more complex and seem not to be any faster when reduced to code. |
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* |
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* This implementation is based on an algorithm described in |
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* C. Loeffler, A. Ligtenberg and G. Moschytz, "Practical Fast 1-D DCT |
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* Algorithms with 11 Multiplications", Proc. Int'l. Conf. on Acoustics, |
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* Speech, and Signal Processing 1989 (ICASSP '89), pp. 988-991. |
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* The primary algorithm described there uses 11 multiplies and 29 adds. |
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* We use their alternate method with 12 multiplies and 32 adds. |
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* The advantage of this method is that no data path contains more than one |
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* multiplication; this allows a very simple and accurate implementation in |
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* scaled fixed-point arithmetic, with a minimal number of shifts. |
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*/ |
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/**
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* @file |
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* Independent JPEG Group's slow & accurate dct. |
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*/ |
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#include <stdlib.h> |
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#include <stdio.h> |
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#include "libavutil/common.h" |
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#include "dsputil.h" |
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#define DCTSIZE 8 |
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#define BITS_IN_JSAMPLE 8 |
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#define GLOBAL(x) x |
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#define RIGHT_SHIFT(x, n) ((x) >> (n)) |
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#define MULTIPLY16C16(var,const) ((var)*(const)) |
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#if 1 //def USE_ACCURATE_ROUNDING
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#define DESCALE(x,n) RIGHT_SHIFT((x) + (1 << ((n) - 1)), n) |
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#else |
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#define DESCALE(x,n) RIGHT_SHIFT(x, n) |
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#endif |
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/*
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* This module is specialized to the case DCTSIZE = 8. |
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*/ |
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#if DCTSIZE != 8 |
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Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */ |
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#endif |
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/*
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* The poop on this scaling stuff is as follows: |
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* |
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* Each 1-D DCT step produces outputs which are a factor of sqrt(N) |
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* larger than the true DCT outputs. The final outputs are therefore |
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* a factor of N larger than desired; since N=8 this can be cured by |
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* a simple right shift at the end of the algorithm. The advantage of |
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* this arrangement is that we save two multiplications per 1-D DCT, |
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* because the y0 and y4 outputs need not be divided by sqrt(N). |
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* In the IJG code, this factor of 8 is removed by the quantization step |
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* (in jcdctmgr.c), NOT in this module. |
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* This file is part of Libav. |
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* |
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* We have to do addition and subtraction of the integer inputs, which |
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* is no problem, and multiplication by fractional constants, which is |
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* a problem to do in integer arithmetic. We multiply all the constants |
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* by CONST_SCALE and convert them to integer constants (thus retaining |
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* CONST_BITS bits of precision in the constants). After doing a |
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* multiplication we have to divide the product by CONST_SCALE, with proper |
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* rounding, to produce the correct output. This division can be done |
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* cheaply as a right shift of CONST_BITS bits. We postpone shifting |
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* as long as possible so that partial sums can be added together with |
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* full fractional precision. |
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* Libav is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* The outputs of the first pass are scaled up by PASS1_BITS bits so that |
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* they are represented to better-than-integral precision. These outputs |
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* require BITS_IN_JSAMPLE + PASS1_BITS + 3 bits; this fits in a 16-bit word |
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* with the recommended scaling. (For 12-bit sample data, the intermediate |
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* array is int32_t anyway.) |
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* Libav is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* To avoid overflow of the 32-bit intermediate results in pass 2, we must |
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* have BITS_IN_JSAMPLE + CONST_BITS + PASS1_BITS <= 26. Error analysis |
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* shows that the values given below are the most effective. |
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*/ |
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#if BITS_IN_JSAMPLE == 8 |
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#define CONST_BITS 13 |
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#define PASS1_BITS 4 /* set this to 2 if 16x16 multiplies are faster */ |
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#else |
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#define CONST_BITS 13 |
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#define PASS1_BITS 1 /* lose a little precision to avoid overflow */ |
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#endif |
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/* Some C compilers fail to reduce "FIX(constant)" at compile time, thus
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* causing a lot of useless floating-point operations at run time. |
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* To get around this we use the following pre-calculated constants. |
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* If you change CONST_BITS you may want to add appropriate values. |
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* (With a reasonable C compiler, you can just rely on the FIX() macro...) |
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*/ |
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#if CONST_BITS == 13 |
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#define FIX_0_298631336 ((int32_t) 2446) /* FIX(0.298631336) */ |
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#define FIX_0_390180644 ((int32_t) 3196) /* FIX(0.390180644) */ |
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#define FIX_0_541196100 ((int32_t) 4433) /* FIX(0.541196100) */ |
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#define FIX_0_765366865 ((int32_t) 6270) /* FIX(0.765366865) */ |
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#define FIX_0_899976223 ((int32_t) 7373) /* FIX(0.899976223) */ |
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#define FIX_1_175875602 ((int32_t) 9633) /* FIX(1.175875602) */ |
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#define FIX_1_501321110 ((int32_t) 12299) /* FIX(1.501321110) */ |
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#define FIX_1_847759065 ((int32_t) 15137) /* FIX(1.847759065) */ |
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#define FIX_1_961570560 ((int32_t) 16069) /* FIX(1.961570560) */ |
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#define FIX_2_053119869 ((int32_t) 16819) /* FIX(2.053119869) */ |
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#define FIX_2_562915447 ((int32_t) 20995) /* FIX(2.562915447) */ |
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#define FIX_3_072711026 ((int32_t) 25172) /* FIX(3.072711026) */ |
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#else |
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#define FIX_0_298631336 FIX(0.298631336) |
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#define FIX_0_390180644 FIX(0.390180644) |
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#define FIX_0_541196100 FIX(0.541196100) |
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#define FIX_0_765366865 FIX(0.765366865) |
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#define FIX_0_899976223 FIX(0.899976223) |
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#define FIX_1_175875602 FIX(1.175875602) |
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#define FIX_1_501321110 FIX(1.501321110) |
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#define FIX_1_847759065 FIX(1.847759065) |
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#define FIX_1_961570560 FIX(1.961570560) |
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#define FIX_2_053119869 FIX(2.053119869) |
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#define FIX_2_562915447 FIX(2.562915447) |
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#define FIX_3_072711026 FIX(3.072711026) |
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#endif |
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/* Multiply an int32_t variable by an int32_t constant to yield an int32_t result.
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* For 8-bit samples with the recommended scaling, all the variable |
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* and constant values involved are no more than 16 bits wide, so a |
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* 16x16->32 bit multiply can be used instead of a full 32x32 multiply. |
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* For 12-bit samples, a full 32-bit multiplication will be needed. |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with Libav; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#if BITS_IN_JSAMPLE == 8 && CONST_BITS<=13 && PASS1_BITS<=2 |
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#define MULTIPLY(var,const) MULTIPLY16C16(var,const) |
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#else |
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#define MULTIPLY(var,const) ((var) * (const)) |
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#endif |
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static av_always_inline void row_fdct(DCTELEM * data){ |
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int tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7; |
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int tmp10, tmp11, tmp12, tmp13; |
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int z1, z2, z3, z4, z5; |
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DCTELEM *dataptr; |
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int ctr; |
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/* Pass 1: process rows. */ |
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/* Note results are scaled up by sqrt(8) compared to a true DCT; */ |
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/* furthermore, we scale the results by 2**PASS1_BITS. */ |
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dataptr = data; |
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for (ctr = DCTSIZE-1; ctr >= 0; ctr--) { |
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tmp0 = dataptr[0] + dataptr[7]; |
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tmp7 = dataptr[0] - dataptr[7]; |
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tmp1 = dataptr[1] + dataptr[6]; |
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tmp6 = dataptr[1] - dataptr[6]; |
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tmp2 = dataptr[2] + dataptr[5]; |
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tmp5 = dataptr[2] - dataptr[5]; |
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tmp3 = dataptr[3] + dataptr[4]; |
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tmp4 = dataptr[3] - dataptr[4]; |
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/* Even part per LL&M figure 1 --- note that published figure is faulty;
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* rotator "sqrt(2)*c1" should be "sqrt(2)*c6". |
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*/ |
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tmp10 = tmp0 + tmp3; |
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tmp13 = tmp0 - tmp3; |
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tmp11 = tmp1 + tmp2; |
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tmp12 = tmp1 - tmp2; |
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dataptr[0] = (DCTELEM) ((tmp10 + tmp11) << PASS1_BITS); |
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dataptr[4] = (DCTELEM) ((tmp10 - tmp11) << PASS1_BITS); |
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z1 = MULTIPLY(tmp12 + tmp13, FIX_0_541196100); |
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dataptr[2] = (DCTELEM) DESCALE(z1 + MULTIPLY(tmp13, FIX_0_765366865), |
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CONST_BITS-PASS1_BITS); |
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dataptr[6] = (DCTELEM) DESCALE(z1 + MULTIPLY(tmp12, - FIX_1_847759065), |
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CONST_BITS-PASS1_BITS); |
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/* Odd part per figure 8 --- note paper omits factor of sqrt(2).
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* cK represents cos(K*pi/16). |
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* i0..i3 in the paper are tmp4..tmp7 here. |
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*/ |
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z1 = tmp4 + tmp7; |
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z2 = tmp5 + tmp6; |
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z3 = tmp4 + tmp6; |
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z4 = tmp5 + tmp7; |
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z5 = MULTIPLY(z3 + z4, FIX_1_175875602); /* sqrt(2) * c3 */ |
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tmp4 = MULTIPLY(tmp4, FIX_0_298631336); /* sqrt(2) * (-c1+c3+c5-c7) */ |
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tmp5 = MULTIPLY(tmp5, FIX_2_053119869); /* sqrt(2) * ( c1+c3-c5+c7) */ |
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tmp6 = MULTIPLY(tmp6, FIX_3_072711026); /* sqrt(2) * ( c1+c3+c5-c7) */ |
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tmp7 = MULTIPLY(tmp7, FIX_1_501321110); /* sqrt(2) * ( c1+c3-c5-c7) */ |
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z1 = MULTIPLY(z1, - FIX_0_899976223); /* sqrt(2) * (c7-c3) */ |
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z2 = MULTIPLY(z2, - FIX_2_562915447); /* sqrt(2) * (-c1-c3) */ |
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z3 = MULTIPLY(z3, - FIX_1_961570560); /* sqrt(2) * (-c3-c5) */ |
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z4 = MULTIPLY(z4, - FIX_0_390180644); /* sqrt(2) * (c5-c3) */ |
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z3 += z5; |
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z4 += z5; |
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dataptr[7] = (DCTELEM) DESCALE(tmp4 + z1 + z3, CONST_BITS-PASS1_BITS); |
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dataptr[5] = (DCTELEM) DESCALE(tmp5 + z2 + z4, CONST_BITS-PASS1_BITS); |
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dataptr[3] = (DCTELEM) DESCALE(tmp6 + z2 + z3, CONST_BITS-PASS1_BITS); |
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dataptr[1] = (DCTELEM) DESCALE(tmp7 + z1 + z4, CONST_BITS-PASS1_BITS); |
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dataptr += DCTSIZE; /* advance pointer to next row */ |
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} |
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} |
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/*
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* Perform the forward DCT on one block of samples. |
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*/ |
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GLOBAL(void) |
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ff_jpeg_fdct_islow (DCTELEM * data) |
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{ |
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int tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7; |
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int tmp10, tmp11, tmp12, tmp13; |
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int z1, z2, z3, z4, z5; |
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DCTELEM *dataptr; |
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int ctr; |
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row_fdct(data); |
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/* Pass 2: process columns.
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* We remove the PASS1_BITS scaling, but leave the results scaled up |
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* by an overall factor of 8. |
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*/ |
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dataptr = data; |
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for (ctr = DCTSIZE-1; ctr >= 0; ctr--) { |
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tmp0 = dataptr[DCTSIZE*0] + dataptr[DCTSIZE*7]; |
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tmp7 = dataptr[DCTSIZE*0] - dataptr[DCTSIZE*7]; |
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tmp1 = dataptr[DCTSIZE*1] + dataptr[DCTSIZE*6]; |
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tmp6 = dataptr[DCTSIZE*1] - dataptr[DCTSIZE*6]; |
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tmp2 = dataptr[DCTSIZE*2] + dataptr[DCTSIZE*5]; |
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tmp5 = dataptr[DCTSIZE*2] - dataptr[DCTSIZE*5]; |
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tmp3 = dataptr[DCTSIZE*3] + dataptr[DCTSIZE*4]; |
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tmp4 = dataptr[DCTSIZE*3] - dataptr[DCTSIZE*4]; |
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/* Even part per LL&M figure 1 --- note that published figure is faulty;
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* rotator "sqrt(2)*c1" should be "sqrt(2)*c6". |
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*/ |
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tmp10 = tmp0 + tmp3; |
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tmp13 = tmp0 - tmp3; |
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tmp11 = tmp1 + tmp2; |
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tmp12 = tmp1 - tmp2; |
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dataptr[DCTSIZE*0] = (DCTELEM) DESCALE(tmp10 + tmp11, PASS1_BITS); |
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dataptr[DCTSIZE*4] = (DCTELEM) DESCALE(tmp10 - tmp11, PASS1_BITS); |
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z1 = MULTIPLY(tmp12 + tmp13, FIX_0_541196100); |
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dataptr[DCTSIZE*2] = (DCTELEM) DESCALE(z1 + MULTIPLY(tmp13, FIX_0_765366865), |
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CONST_BITS+PASS1_BITS); |
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dataptr[DCTSIZE*6] = (DCTELEM) DESCALE(z1 + MULTIPLY(tmp12, - FIX_1_847759065), |
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CONST_BITS+PASS1_BITS); |
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/* Odd part per figure 8 --- note paper omits factor of sqrt(2).
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* cK represents cos(K*pi/16). |
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* i0..i3 in the paper are tmp4..tmp7 here. |
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*/ |
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z1 = tmp4 + tmp7; |
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z2 = tmp5 + tmp6; |
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z3 = tmp4 + tmp6; |
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z4 = tmp5 + tmp7; |
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z5 = MULTIPLY(z3 + z4, FIX_1_175875602); /* sqrt(2) * c3 */ |
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tmp4 = MULTIPLY(tmp4, FIX_0_298631336); /* sqrt(2) * (-c1+c3+c5-c7) */ |
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tmp5 = MULTIPLY(tmp5, FIX_2_053119869); /* sqrt(2) * ( c1+c3-c5+c7) */ |
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tmp6 = MULTIPLY(tmp6, FIX_3_072711026); /* sqrt(2) * ( c1+c3+c5-c7) */ |
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tmp7 = MULTIPLY(tmp7, FIX_1_501321110); /* sqrt(2) * ( c1+c3-c5-c7) */ |
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z1 = MULTIPLY(z1, - FIX_0_899976223); /* sqrt(2) * (c7-c3) */ |
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z2 = MULTIPLY(z2, - FIX_2_562915447); /* sqrt(2) * (-c1-c3) */ |
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z3 = MULTIPLY(z3, - FIX_1_961570560); /* sqrt(2) * (-c3-c5) */ |
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z4 = MULTIPLY(z4, - FIX_0_390180644); /* sqrt(2) * (c5-c3) */ |
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z3 += z5; |
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z4 += z5; |
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dataptr[DCTSIZE*7] = (DCTELEM) DESCALE(tmp4 + z1 + z3, |
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CONST_BITS+PASS1_BITS); |
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dataptr[DCTSIZE*5] = (DCTELEM) DESCALE(tmp5 + z2 + z4, |
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CONST_BITS+PASS1_BITS); |
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dataptr[DCTSIZE*3] = (DCTELEM) DESCALE(tmp6 + z2 + z3, |
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CONST_BITS+PASS1_BITS); |
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dataptr[DCTSIZE*1] = (DCTELEM) DESCALE(tmp7 + z1 + z4, |
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CONST_BITS+PASS1_BITS); |
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dataptr++; /* advance pointer to next column */ |
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} |
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} |
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/*
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* The secret of DCT2-4-8 is really simple -- you do the usual 1-DCT |
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* on the rows and then, instead of doing even and odd, part on the colums |
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* you do even part two times. |
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*/ |
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GLOBAL(void) |
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ff_fdct248_islow (DCTELEM * data) |
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{ |
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int tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7; |
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int tmp10, tmp11, tmp12, tmp13; |
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int z1; |
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DCTELEM *dataptr; |
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int ctr; |
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row_fdct(data); |
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/* Pass 2: process columns.
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* We remove the PASS1_BITS scaling, but leave the results scaled up |
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* by an overall factor of 8. |
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*/ |
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dataptr = data; |
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for (ctr = DCTSIZE-1; ctr >= 0; ctr--) { |
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tmp0 = dataptr[DCTSIZE*0] + dataptr[DCTSIZE*1]; |
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tmp1 = dataptr[DCTSIZE*2] + dataptr[DCTSIZE*3]; |
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tmp2 = dataptr[DCTSIZE*4] + dataptr[DCTSIZE*5]; |
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tmp3 = dataptr[DCTSIZE*6] + dataptr[DCTSIZE*7]; |
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tmp4 = dataptr[DCTSIZE*0] - dataptr[DCTSIZE*1]; |
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tmp5 = dataptr[DCTSIZE*2] - dataptr[DCTSIZE*3]; |
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tmp6 = dataptr[DCTSIZE*4] - dataptr[DCTSIZE*5]; |
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tmp7 = dataptr[DCTSIZE*6] - dataptr[DCTSIZE*7]; |
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tmp10 = tmp0 + tmp3; |
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tmp11 = tmp1 + tmp2; |
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tmp12 = tmp1 - tmp2; |
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tmp13 = tmp0 - tmp3; |
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dataptr[DCTSIZE*0] = (DCTELEM) DESCALE(tmp10 + tmp11, PASS1_BITS); |
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dataptr[DCTSIZE*4] = (DCTELEM) DESCALE(tmp10 - tmp11, PASS1_BITS); |
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z1 = MULTIPLY(tmp12 + tmp13, FIX_0_541196100); |
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dataptr[DCTSIZE*2] = (DCTELEM) DESCALE(z1 + MULTIPLY(tmp13, FIX_0_765366865), |
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CONST_BITS+PASS1_BITS); |
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dataptr[DCTSIZE*6] = (DCTELEM) DESCALE(z1 + MULTIPLY(tmp12, - FIX_1_847759065), |
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CONST_BITS+PASS1_BITS); |
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tmp10 = tmp4 + tmp7; |
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tmp11 = tmp5 + tmp6; |
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tmp12 = tmp5 - tmp6; |
||||
tmp13 = tmp4 - tmp7; |
||||
|
||||
dataptr[DCTSIZE*1] = (DCTELEM) DESCALE(tmp10 + tmp11, PASS1_BITS); |
||||
dataptr[DCTSIZE*5] = (DCTELEM) DESCALE(tmp10 - tmp11, PASS1_BITS); |
||||
|
||||
z1 = MULTIPLY(tmp12 + tmp13, FIX_0_541196100); |
||||
dataptr[DCTSIZE*3] = (DCTELEM) DESCALE(z1 + MULTIPLY(tmp13, FIX_0_765366865), |
||||
CONST_BITS+PASS1_BITS); |
||||
dataptr[DCTSIZE*7] = (DCTELEM) DESCALE(z1 + MULTIPLY(tmp12, - FIX_1_847759065), |
||||
CONST_BITS+PASS1_BITS); |
||||
#define BIT_DEPTH 8 |
||||
#include "jfdctint_template.c" |
||||
#undef BIT_DEPTH |
||||
|
||||
dataptr++; /* advance pointer to next column */ |
||||
} |
||||
} |
||||
#define BIT_DEPTH 10 |
||||
#include "jfdctint_template.c" |
||||
#undef BIT_DEPTH |
||||
|
@ -0,0 +1,405 @@ |
||||
/*
|
||||
* jfdctint.c |
||||
* |
||||
* This file is part of the Independent JPEG Group's software. |
||||
* |
||||
* The authors make NO WARRANTY or representation, either express or implied, |
||||
* with respect to this software, its quality, accuracy, merchantability, or |
||||
* fitness for a particular purpose. This software is provided "AS IS", and |
||||
* you, its user, assume the entire risk as to its quality and accuracy. |
||||
* |
||||
* This software is copyright (C) 1991-1996, Thomas G. Lane. |
||||
* All Rights Reserved except as specified below. |
||||
* |
||||
* Permission is hereby granted to use, copy, modify, and distribute this |
||||
* software (or portions thereof) for any purpose, without fee, subject to |
||||
* these conditions: |
||||
* (1) If any part of the source code for this software is distributed, then |
||||
* this README file must be included, with this copyright and no-warranty |
||||
* notice unaltered; and any additions, deletions, or changes to the original |
||||
* files must be clearly indicated in accompanying documentation. |
||||
* (2) If only executable code is distributed, then the accompanying |
||||
* documentation must state that "this software is based in part on the work |
||||
* of the Independent JPEG Group". |
||||
* (3) Permission for use of this software is granted only if the user accepts |
||||
* full responsibility for any undesirable consequences; the authors accept |
||||
* NO LIABILITY for damages of any kind. |
||||
* |
||||
* These conditions apply to any software derived from or based on the IJG |
||||
* code, not just to the unmodified library. If you use our work, you ought |
||||
* to acknowledge us. |
||||
* |
||||
* Permission is NOT granted for the use of any IJG author's name or company |
||||
* name in advertising or publicity relating to this software or products |
||||
* derived from it. This software may be referred to only as "the Independent |
||||
* JPEG Group's software". |
||||
* |
||||
* We specifically permit and encourage the use of this software as the basis |
||||
* of commercial products, provided that all warranty or liability claims are |
||||
* assumed by the product vendor. |
||||
* |
||||
* This file contains a slow-but-accurate integer implementation of the |
||||
* forward DCT (Discrete Cosine Transform). |
||||
* |
||||
* A 2-D DCT can be done by 1-D DCT on each row followed by 1-D DCT |
||||
* on each column. Direct algorithms are also available, but they are |
||||
* much more complex and seem not to be any faster when reduced to code. |
||||
* |
||||
* This implementation is based on an algorithm described in |
||||
* C. Loeffler, A. Ligtenberg and G. Moschytz, "Practical Fast 1-D DCT |
||||
* Algorithms with 11 Multiplications", Proc. Int'l. Conf. on Acoustics, |
||||
* Speech, and Signal Processing 1989 (ICASSP '89), pp. 988-991. |
||||
* The primary algorithm described there uses 11 multiplies and 29 adds. |
||||
* We use their alternate method with 12 multiplies and 32 adds. |
||||
* The advantage of this method is that no data path contains more than one |
||||
* multiplication; this allows a very simple and accurate implementation in |
||||
* scaled fixed-point arithmetic, with a minimal number of shifts. |
||||
*/ |
||||
|
||||
/**
|
||||
* @file |
||||
* Independent JPEG Group's slow & accurate dct. |
||||
*/ |
||||
|
||||
#include "libavutil/common.h" |
||||
#include "dsputil.h" |
||||
|
||||
#include "bit_depth_template.c" |
||||
|
||||
#define DCTSIZE 8 |
||||
#define BITS_IN_JSAMPLE BIT_DEPTH |
||||
#define GLOBAL(x) x |
||||
#define RIGHT_SHIFT(x, n) ((x) >> (n)) |
||||
#define MULTIPLY16C16(var,const) ((var)*(const)) |
||||
|
||||
#if 1 //def USE_ACCURATE_ROUNDING
|
||||
#define DESCALE(x,n) RIGHT_SHIFT((x) + (1 << ((n) - 1)), n) |
||||
#else |
||||
#define DESCALE(x,n) RIGHT_SHIFT(x, n) |
||||
#endif |
||||
|
||||
|
||||
/*
|
||||
* This module is specialized to the case DCTSIZE = 8. |
||||
*/ |
||||
|
||||
#if DCTSIZE != 8 |
||||
#error "Sorry, this code only copes with 8x8 DCTs." |
||||
#endif |
||||
|
||||
|
||||
/*
|
||||
* The poop on this scaling stuff is as follows: |
||||
* |
||||
* Each 1-D DCT step produces outputs which are a factor of sqrt(N) |
||||
* larger than the true DCT outputs. The final outputs are therefore |
||||
* a factor of N larger than desired; since N=8 this can be cured by |
||||
* a simple right shift at the end of the algorithm. The advantage of |
||||
* this arrangement is that we save two multiplications per 1-D DCT, |
||||
* because the y0 and y4 outputs need not be divided by sqrt(N). |
||||
* In the IJG code, this factor of 8 is removed by the quantization step |
||||
* (in jcdctmgr.c), NOT in this module. |
||||
* |
||||
* We have to do addition and subtraction of the integer inputs, which |
||||
* is no problem, and multiplication by fractional constants, which is |
||||
* a problem to do in integer arithmetic. We multiply all the constants |
||||
* by CONST_SCALE and convert them to integer constants (thus retaining |
||||
* CONST_BITS bits of precision in the constants). After doing a |
||||
* multiplication we have to divide the product by CONST_SCALE, with proper |
||||
* rounding, to produce the correct output. This division can be done |
||||
* cheaply as a right shift of CONST_BITS bits. We postpone shifting |
||||
* as long as possible so that partial sums can be added together with |
||||
* full fractional precision. |
||||
* |
||||
* The outputs of the first pass are scaled up by PASS1_BITS bits so that |
||||
* they are represented to better-than-integral precision. These outputs |
||||
* require BITS_IN_JSAMPLE + PASS1_BITS + 3 bits; this fits in a 16-bit word |
||||
* with the recommended scaling. (For 12-bit sample data, the intermediate |
||||
* array is int32_t anyway.) |
||||
* |
||||
* To avoid overflow of the 32-bit intermediate results in pass 2, we must |
||||
* have BITS_IN_JSAMPLE + CONST_BITS + PASS1_BITS <= 26. Error analysis |
||||
* shows that the values given below are the most effective. |
||||
*/ |
||||
|
||||
#undef CONST_BITS |
||||
#undef PASS1_BITS |
||||
#undef OUT_SHIFT |
||||
|
||||
#if BITS_IN_JSAMPLE == 8 |
||||
#define CONST_BITS 13 |
||||
#define PASS1_BITS 4 /* set this to 2 if 16x16 multiplies are faster */ |
||||
#define OUT_SHIFT PASS1_BITS |
||||
#else |
||||
#define CONST_BITS 13 |
||||
#define PASS1_BITS 1 /* lose a little precision to avoid overflow */ |
||||
#define OUT_SHIFT (PASS1_BITS + 1) |
||||
#endif |
||||
|
||||
/* Some C compilers fail to reduce "FIX(constant)" at compile time, thus
|
||||
* causing a lot of useless floating-point operations at run time. |
||||
* To get around this we use the following pre-calculated constants. |
||||
* If you change CONST_BITS you may want to add appropriate values. |
||||
* (With a reasonable C compiler, you can just rely on the FIX() macro...) |
||||
*/ |
||||
|
||||
#if CONST_BITS == 13 |
||||
#define FIX_0_298631336 ((int32_t) 2446) /* FIX(0.298631336) */ |
||||
#define FIX_0_390180644 ((int32_t) 3196) /* FIX(0.390180644) */ |
||||
#define FIX_0_541196100 ((int32_t) 4433) /* FIX(0.541196100) */ |
||||
#define FIX_0_765366865 ((int32_t) 6270) /* FIX(0.765366865) */ |
||||
#define FIX_0_899976223 ((int32_t) 7373) /* FIX(0.899976223) */ |
||||
#define FIX_1_175875602 ((int32_t) 9633) /* FIX(1.175875602) */ |
||||
#define FIX_1_501321110 ((int32_t) 12299) /* FIX(1.501321110) */ |
||||
#define FIX_1_847759065 ((int32_t) 15137) /* FIX(1.847759065) */ |
||||
#define FIX_1_961570560 ((int32_t) 16069) /* FIX(1.961570560) */ |
||||
#define FIX_2_053119869 ((int32_t) 16819) /* FIX(2.053119869) */ |
||||
#define FIX_2_562915447 ((int32_t) 20995) /* FIX(2.562915447) */ |
||||
#define FIX_3_072711026 ((int32_t) 25172) /* FIX(3.072711026) */ |
||||
#else |
||||
#define FIX_0_298631336 FIX(0.298631336) |
||||
#define FIX_0_390180644 FIX(0.390180644) |
||||
#define FIX_0_541196100 FIX(0.541196100) |
||||
#define FIX_0_765366865 FIX(0.765366865) |
||||
#define FIX_0_899976223 FIX(0.899976223) |
||||
#define FIX_1_175875602 FIX(1.175875602) |
||||
#define FIX_1_501321110 FIX(1.501321110) |
||||
#define FIX_1_847759065 FIX(1.847759065) |
||||
#define FIX_1_961570560 FIX(1.961570560) |
||||
#define FIX_2_053119869 FIX(2.053119869) |
||||
#define FIX_2_562915447 FIX(2.562915447) |
||||
#define FIX_3_072711026 FIX(3.072711026) |
||||
#endif |
||||
|
||||
|
||||
/* Multiply an int32_t variable by an int32_t constant to yield an int32_t result.
|
||||
* For 8-bit samples with the recommended scaling, all the variable |
||||
* and constant values involved are no more than 16 bits wide, so a |
||||
* 16x16->32 bit multiply can be used instead of a full 32x32 multiply. |
||||
* For 12-bit samples, a full 32-bit multiplication will be needed. |
||||
*/ |
||||
|
||||
#if BITS_IN_JSAMPLE == 8 && CONST_BITS<=13 && PASS1_BITS<=2 |
||||
#define MULTIPLY(var,const) MULTIPLY16C16(var,const) |
||||
#else |
||||
#define MULTIPLY(var,const) ((var) * (const)) |
||||
#endif |
||||
|
||||
|
||||
static av_always_inline void FUNC(row_fdct)(DCTELEM *data) |
||||
{ |
||||
int tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7; |
||||
int tmp10, tmp11, tmp12, tmp13; |
||||
int z1, z2, z3, z4, z5; |
||||
DCTELEM *dataptr; |
||||
int ctr; |
||||
|
||||
/* Pass 1: process rows. */ |
||||
/* Note results are scaled up by sqrt(8) compared to a true DCT; */ |
||||
/* furthermore, we scale the results by 2**PASS1_BITS. */ |
||||
|
||||
dataptr = data; |
||||
for (ctr = DCTSIZE-1; ctr >= 0; ctr--) { |
||||
tmp0 = dataptr[0] + dataptr[7]; |
||||
tmp7 = dataptr[0] - dataptr[7]; |
||||
tmp1 = dataptr[1] + dataptr[6]; |
||||
tmp6 = dataptr[1] - dataptr[6]; |
||||
tmp2 = dataptr[2] + dataptr[5]; |
||||
tmp5 = dataptr[2] - dataptr[5]; |
||||
tmp3 = dataptr[3] + dataptr[4]; |
||||
tmp4 = dataptr[3] - dataptr[4]; |
||||
|
||||
/* Even part per LL&M figure 1 --- note that published figure is faulty;
|
||||
* rotator "sqrt(2)*c1" should be "sqrt(2)*c6". |
||||
*/ |
||||
|
||||
tmp10 = tmp0 + tmp3; |
||||
tmp13 = tmp0 - tmp3; |
||||
tmp11 = tmp1 + tmp2; |
||||
tmp12 = tmp1 - tmp2; |
||||
|
||||
dataptr[0] = (DCTELEM) ((tmp10 + tmp11) << PASS1_BITS); |
||||
dataptr[4] = (DCTELEM) ((tmp10 - tmp11) << PASS1_BITS); |
||||
|
||||
z1 = MULTIPLY(tmp12 + tmp13, FIX_0_541196100); |
||||
dataptr[2] = (DCTELEM) DESCALE(z1 + MULTIPLY(tmp13, FIX_0_765366865), |
||||
CONST_BITS-PASS1_BITS); |
||||
dataptr[6] = (DCTELEM) DESCALE(z1 + MULTIPLY(tmp12, - FIX_1_847759065), |
||||
CONST_BITS-PASS1_BITS); |
||||
|
||||
/* Odd part per figure 8 --- note paper omits factor of sqrt(2).
|
||||
* cK represents cos(K*pi/16). |
||||
* i0..i3 in the paper are tmp4..tmp7 here. |
||||
*/ |
||||
|
||||
z1 = tmp4 + tmp7; |
||||
z2 = tmp5 + tmp6; |
||||
z3 = tmp4 + tmp6; |
||||
z4 = tmp5 + tmp7; |
||||
z5 = MULTIPLY(z3 + z4, FIX_1_175875602); /* sqrt(2) * c3 */ |
||||
|
||||
tmp4 = MULTIPLY(tmp4, FIX_0_298631336); /* sqrt(2) * (-c1+c3+c5-c7) */ |
||||
tmp5 = MULTIPLY(tmp5, FIX_2_053119869); /* sqrt(2) * ( c1+c3-c5+c7) */ |
||||
tmp6 = MULTIPLY(tmp6, FIX_3_072711026); /* sqrt(2) * ( c1+c3+c5-c7) */ |
||||
tmp7 = MULTIPLY(tmp7, FIX_1_501321110); /* sqrt(2) * ( c1+c3-c5-c7) */ |
||||
z1 = MULTIPLY(z1, - FIX_0_899976223); /* sqrt(2) * (c7-c3) */ |
||||
z2 = MULTIPLY(z2, - FIX_2_562915447); /* sqrt(2) * (-c1-c3) */ |
||||
z3 = MULTIPLY(z3, - FIX_1_961570560); /* sqrt(2) * (-c3-c5) */ |
||||
z4 = MULTIPLY(z4, - FIX_0_390180644); /* sqrt(2) * (c5-c3) */ |
||||
|
||||
z3 += z5; |
||||
z4 += z5; |
||||
|
||||
dataptr[7] = (DCTELEM) DESCALE(tmp4 + z1 + z3, CONST_BITS-PASS1_BITS); |
||||
dataptr[5] = (DCTELEM) DESCALE(tmp5 + z2 + z4, CONST_BITS-PASS1_BITS); |
||||
dataptr[3] = (DCTELEM) DESCALE(tmp6 + z2 + z3, CONST_BITS-PASS1_BITS); |
||||
dataptr[1] = (DCTELEM) DESCALE(tmp7 + z1 + z4, CONST_BITS-PASS1_BITS); |
||||
|
||||
dataptr += DCTSIZE; /* advance pointer to next row */ |
||||
} |
||||
} |
||||
|
||||
/*
|
||||
* Perform the forward DCT on one block of samples. |
||||
*/ |
||||
|
||||
GLOBAL(void) |
||||
FUNC(ff_jpeg_fdct_islow)(DCTELEM *data) |
||||
{ |
||||
int tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7; |
||||
int tmp10, tmp11, tmp12, tmp13; |
||||
int z1, z2, z3, z4, z5; |
||||
DCTELEM *dataptr; |
||||
int ctr; |
||||
|
||||
FUNC(row_fdct)(data); |
||||
|
||||
/* Pass 2: process columns.
|
||||
* We remove the PASS1_BITS scaling, but leave the results scaled up |
||||
* by an overall factor of 8. |
||||
*/ |
||||
|
||||
dataptr = data; |
||||
for (ctr = DCTSIZE-1; ctr >= 0; ctr--) { |
||||
tmp0 = dataptr[DCTSIZE*0] + dataptr[DCTSIZE*7]; |
||||
tmp7 = dataptr[DCTSIZE*0] - dataptr[DCTSIZE*7]; |
||||
tmp1 = dataptr[DCTSIZE*1] + dataptr[DCTSIZE*6]; |
||||
tmp6 = dataptr[DCTSIZE*1] - dataptr[DCTSIZE*6]; |
||||
tmp2 = dataptr[DCTSIZE*2] + dataptr[DCTSIZE*5]; |
||||
tmp5 = dataptr[DCTSIZE*2] - dataptr[DCTSIZE*5]; |
||||
tmp3 = dataptr[DCTSIZE*3] + dataptr[DCTSIZE*4]; |
||||
tmp4 = dataptr[DCTSIZE*3] - dataptr[DCTSIZE*4]; |
||||
|
||||
/* Even part per LL&M figure 1 --- note that published figure is faulty;
|
||||
* rotator "sqrt(2)*c1" should be "sqrt(2)*c6". |
||||
*/ |
||||
|
||||
tmp10 = tmp0 + tmp3; |
||||
tmp13 = tmp0 - tmp3; |
||||
tmp11 = tmp1 + tmp2; |
||||
tmp12 = tmp1 - tmp2; |
||||
|
||||
dataptr[DCTSIZE*0] = DESCALE(tmp10 + tmp11, OUT_SHIFT); |
||||
dataptr[DCTSIZE*4] = DESCALE(tmp10 - tmp11, OUT_SHIFT); |
||||
|
||||
z1 = MULTIPLY(tmp12 + tmp13, FIX_0_541196100); |
||||
dataptr[DCTSIZE*2] = DESCALE(z1 + MULTIPLY(tmp13, FIX_0_765366865), |
||||
CONST_BITS + OUT_SHIFT); |
||||
dataptr[DCTSIZE*6] = DESCALE(z1 + MULTIPLY(tmp12, - FIX_1_847759065), |
||||
CONST_BITS + OUT_SHIFT); |
||||
|
||||
/* Odd part per figure 8 --- note paper omits factor of sqrt(2).
|
||||
* cK represents cos(K*pi/16). |
||||
* i0..i3 in the paper are tmp4..tmp7 here. |
||||
*/ |
||||
|
||||
z1 = tmp4 + tmp7; |
||||
z2 = tmp5 + tmp6; |
||||
z3 = tmp4 + tmp6; |
||||
z4 = tmp5 + tmp7; |
||||
z5 = MULTIPLY(z3 + z4, FIX_1_175875602); /* sqrt(2) * c3 */ |
||||
|
||||
tmp4 = MULTIPLY(tmp4, FIX_0_298631336); /* sqrt(2) * (-c1+c3+c5-c7) */ |
||||
tmp5 = MULTIPLY(tmp5, FIX_2_053119869); /* sqrt(2) * ( c1+c3-c5+c7) */ |
||||
tmp6 = MULTIPLY(tmp6, FIX_3_072711026); /* sqrt(2) * ( c1+c3+c5-c7) */ |
||||
tmp7 = MULTIPLY(tmp7, FIX_1_501321110); /* sqrt(2) * ( c1+c3-c5-c7) */ |
||||
z1 = MULTIPLY(z1, - FIX_0_899976223); /* sqrt(2) * (c7-c3) */ |
||||
z2 = MULTIPLY(z2, - FIX_2_562915447); /* sqrt(2) * (-c1-c3) */ |
||||
z3 = MULTIPLY(z3, - FIX_1_961570560); /* sqrt(2) * (-c3-c5) */ |
||||
z4 = MULTIPLY(z4, - FIX_0_390180644); /* sqrt(2) * (c5-c3) */ |
||||
|
||||
z3 += z5; |
||||
z4 += z5; |
||||
|
||||
dataptr[DCTSIZE*7] = DESCALE(tmp4 + z1 + z3, CONST_BITS + OUT_SHIFT); |
||||
dataptr[DCTSIZE*5] = DESCALE(tmp5 + z2 + z4, CONST_BITS + OUT_SHIFT); |
||||
dataptr[DCTSIZE*3] = DESCALE(tmp6 + z2 + z3, CONST_BITS + OUT_SHIFT); |
||||
dataptr[DCTSIZE*1] = DESCALE(tmp7 + z1 + z4, CONST_BITS + OUT_SHIFT); |
||||
|
||||
dataptr++; /* advance pointer to next column */ |
||||
} |
||||
} |
||||
|
||||
/*
|
||||
* The secret of DCT2-4-8 is really simple -- you do the usual 1-DCT |
||||
* on the rows and then, instead of doing even and odd, part on the colums |
||||
* you do even part two times. |
||||
*/ |
||||
GLOBAL(void) |
||||
FUNC(ff_fdct248_islow)(DCTELEM *data) |
||||
{ |
||||
int tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7; |
||||
int tmp10, tmp11, tmp12, tmp13; |
||||
int z1; |
||||
DCTELEM *dataptr; |
||||
int ctr; |
||||
|
||||
FUNC(row_fdct)(data); |
||||
|
||||
/* Pass 2: process columns.
|
||||
* We remove the PASS1_BITS scaling, but leave the results scaled up |
||||
* by an overall factor of 8. |
||||
*/ |
||||
|
||||
dataptr = data; |
||||
for (ctr = DCTSIZE-1; ctr >= 0; ctr--) { |
||||
tmp0 = dataptr[DCTSIZE*0] + dataptr[DCTSIZE*1]; |
||||
tmp1 = dataptr[DCTSIZE*2] + dataptr[DCTSIZE*3]; |
||||
tmp2 = dataptr[DCTSIZE*4] + dataptr[DCTSIZE*5]; |
||||
tmp3 = dataptr[DCTSIZE*6] + dataptr[DCTSIZE*7]; |
||||
tmp4 = dataptr[DCTSIZE*0] - dataptr[DCTSIZE*1]; |
||||
tmp5 = dataptr[DCTSIZE*2] - dataptr[DCTSIZE*3]; |
||||
tmp6 = dataptr[DCTSIZE*4] - dataptr[DCTSIZE*5]; |
||||
tmp7 = dataptr[DCTSIZE*6] - dataptr[DCTSIZE*7]; |
||||
|
||||
tmp10 = tmp0 + tmp3; |
||||
tmp11 = tmp1 + tmp2; |
||||
tmp12 = tmp1 - tmp2; |
||||
tmp13 = tmp0 - tmp3; |
||||
|
||||
dataptr[DCTSIZE*0] = DESCALE(tmp10 + tmp11, OUT_SHIFT); |
||||
dataptr[DCTSIZE*4] = DESCALE(tmp10 - tmp11, OUT_SHIFT); |
||||
|
||||
z1 = MULTIPLY(tmp12 + tmp13, FIX_0_541196100); |
||||
dataptr[DCTSIZE*2] = DESCALE(z1 + MULTIPLY(tmp13, FIX_0_765366865), |
||||
CONST_BITS+OUT_SHIFT); |
||||
dataptr[DCTSIZE*6] = DESCALE(z1 + MULTIPLY(tmp12, - FIX_1_847759065), |
||||
CONST_BITS+OUT_SHIFT); |
||||
|
||||
tmp10 = tmp4 + tmp7; |
||||
tmp11 = tmp5 + tmp6; |
||||
tmp12 = tmp5 - tmp6; |
||||
tmp13 = tmp4 - tmp7; |
||||
|
||||
dataptr[DCTSIZE*1] = DESCALE(tmp10 + tmp11, OUT_SHIFT); |
||||
dataptr[DCTSIZE*5] = DESCALE(tmp10 - tmp11, OUT_SHIFT); |
||||
|
||||
z1 = MULTIPLY(tmp12 + tmp13, FIX_0_541196100); |
||||
dataptr[DCTSIZE*3] = DESCALE(z1 + MULTIPLY(tmp13, FIX_0_765366865), |
||||
CONST_BITS + OUT_SHIFT); |
||||
dataptr[DCTSIZE*7] = DESCALE(z1 + MULTIPLY(tmp12, - FIX_1_847759065), |
||||
CONST_BITS + OUT_SHIFT); |
||||
|
||||
dataptr++; /* advance pointer to next column */ |
||||
} |
||||
} |
Loading…
Reference in new issue