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Diffstat (limited to 'media/ffvpx/libavcodec/jfdctint_template.c')
| -rw-r--r-- | media/ffvpx/libavcodec/jfdctint_template.c | 398 |
1 files changed, 398 insertions, 0 deletions
diff --git a/media/ffvpx/libavcodec/jfdctint_template.c b/media/ffvpx/libavcodec/jfdctint_template.c new file mode 100644 index 0000000000..67fb77b5e1 --- /dev/null +++ b/media/ffvpx/libavcodec/jfdctint_template.c @@ -0,0 +1,398 @@ +/* + * 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 "dct.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)) +#define DESCALE(x,n) RIGHT_SHIFT((x) + (1 << ((n) - 1)), n) + + +/* + * 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)(int16_t *data) +{ + int tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7; + int tmp10, tmp11, tmp12, tmp13; + int z1, z2, z3, z4, z5; + int16_t *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] = (int16_t) ((tmp10 + tmp11) * (1 << PASS1_BITS)); + dataptr[4] = (int16_t) ((tmp10 - tmp11) * (1 << PASS1_BITS)); + + z1 = MULTIPLY(tmp12 + tmp13, FIX_0_541196100); + dataptr[2] = (int16_t) DESCALE(z1 + MULTIPLY(tmp13, FIX_0_765366865), + CONST_BITS-PASS1_BITS); + dataptr[6] = (int16_t) 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] = (int16_t) DESCALE(tmp4 + z1 + z3, CONST_BITS-PASS1_BITS); + dataptr[5] = (int16_t) DESCALE(tmp5 + z2 + z4, CONST_BITS-PASS1_BITS); + dataptr[3] = (int16_t) DESCALE(tmp6 + z2 + z3, CONST_BITS-PASS1_BITS); + dataptr[1] = (int16_t) 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)(int16_t *data) +{ + int tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7; + int tmp10, tmp11, tmp12, tmp13; + int z1, z2, z3, z4, z5; + int16_t *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 columns + * you do even part two times. + */ +GLOBAL(void) +FUNC(ff_fdct248_islow)(int16_t *data) +{ + int tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7; + int tmp10, tmp11, tmp12, tmp13; + int z1; + int16_t *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 */ + } +} |