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159 lines
5.0 KiB
159 lines
5.0 KiB
/* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg 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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* FFmpeg 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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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; 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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#include <stdint.h> |
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#include "libavutil/avutil.h" |
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#include "mathops.h" |
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#undef FUNC |
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#undef sum_type |
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#undef MUL |
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#undef CLIP |
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#undef FSUF |
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#define FUNC(n) AV_JOIN(n ## _, SAMPLE_SIZE) |
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#if SAMPLE_SIZE == 32 |
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# define sum_type int64_t |
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# define MUL(a, b) MUL64(a, b) |
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# define CLIP(x) av_clipl_int32(x) |
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#else |
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# define sum_type int32_t |
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# define MUL(a, b) ((a) * (b)) |
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# define CLIP(x) (x) |
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#endif |
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#define LPC1(x) { \ |
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int c = coefs[(x)-1]; \ |
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p0 += MUL(c, s); \ |
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s = smp[i-(x)+1]; \ |
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p1 += MUL(c, s); \ |
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} |
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static av_always_inline void FUNC(lpc_encode_unrolled)(int32_t *res, |
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const int32_t *smp, int len, int order, |
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const int32_t *coefs, int shift, int big) |
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{ |
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int i; |
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for (i = order; i < len; i += 2) { |
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int s = smp[i-order]; |
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sum_type p0 = 0, p1 = 0; |
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if (big) { |
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switch (order) { |
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case 32: LPC1(32) |
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case 31: LPC1(31) |
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case 30: LPC1(30) |
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case 29: LPC1(29) |
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case 28: LPC1(28) |
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case 27: LPC1(27) |
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case 26: LPC1(26) |
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case 25: LPC1(25) |
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case 24: LPC1(24) |
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case 23: LPC1(23) |
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case 22: LPC1(22) |
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case 21: LPC1(21) |
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case 20: LPC1(20) |
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case 19: LPC1(19) |
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case 18: LPC1(18) |
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case 17: LPC1(17) |
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case 16: LPC1(16) |
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case 15: LPC1(15) |
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case 14: LPC1(14) |
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case 13: LPC1(13) |
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case 12: LPC1(12) |
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case 11: LPC1(11) |
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case 10: LPC1(10) |
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case 9: LPC1( 9) |
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LPC1( 8) |
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LPC1( 7) |
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LPC1( 6) |
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LPC1( 5) |
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LPC1( 4) |
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LPC1( 3) |
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LPC1( 2) |
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LPC1( 1) |
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} |
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} else { |
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switch (order) { |
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case 8: LPC1( 8) |
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case 7: LPC1( 7) |
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case 6: LPC1( 6) |
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case 5: LPC1( 5) |
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case 4: LPC1( 4) |
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case 3: LPC1( 3) |
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case 2: LPC1( 2) |
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case 1: LPC1( 1) |
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} |
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} |
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res[i ] = smp[i ] - CLIP(p0 >> shift); |
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res[i+1] = smp[i+1] - CLIP(p1 >> shift); |
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} |
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} |
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static void FUNC(flac_lpc_encode_c)(int32_t *res, const int32_t *smp, int len, |
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int order, const int32_t *coefs, int shift) |
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{ |
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int i; |
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for (i = 0; i < order; i++) |
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res[i] = smp[i]; |
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#if CONFIG_SMALL |
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for (i = order; i < len; i += 2) { |
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int j; |
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int s = smp[i]; |
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sum_type p0 = 0, p1 = 0; |
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for (j = 0; j < order; j++) { |
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int c = coefs[j]; |
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p1 += MUL(c, s); |
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s = smp[i-j-1]; |
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p0 += MUL(c, s); |
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} |
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res[i ] = smp[i ] - CLIP(p0 >> shift); |
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res[i+1] = smp[i+1] - CLIP(p1 >> shift); |
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} |
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#else |
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switch (order) { |
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case 1: FUNC(lpc_encode_unrolled)(res, smp, len, 1, coefs, shift, 0); break; |
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case 2: FUNC(lpc_encode_unrolled)(res, smp, len, 2, coefs, shift, 0); break; |
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case 3: FUNC(lpc_encode_unrolled)(res, smp, len, 3, coefs, shift, 0); break; |
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case 4: FUNC(lpc_encode_unrolled)(res, smp, len, 4, coefs, shift, 0); break; |
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case 5: FUNC(lpc_encode_unrolled)(res, smp, len, 5, coefs, shift, 0); break; |
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case 6: FUNC(lpc_encode_unrolled)(res, smp, len, 6, coefs, shift, 0); break; |
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case 7: FUNC(lpc_encode_unrolled)(res, smp, len, 7, coefs, shift, 0); break; |
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case 8: FUNC(lpc_encode_unrolled)(res, smp, len, 8, coefs, shift, 0); break; |
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default: FUNC(lpc_encode_unrolled)(res, smp, len, order, coefs, shift, 1); break; |
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} |
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#endif |
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} |
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/* Comment for clarity/de-obfuscation. |
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* |
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* for (int i = order; i < len; i++) { |
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* int32_t p = 0; |
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* for (int j = 0; j < order; j++) { |
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* int c = coefs[j]; |
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* int s = smp[(i-1)-j]; |
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* p += c*s; |
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* } |
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* res[i] = smp[i] - (p >> shift); |
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* } |
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* |
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* The CONFIG_SMALL code above simplifies to this, in the case of SAMPLE_SIZE |
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* not being equal to 32 (at the present time that means for 16-bit audio). The |
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* code above does 2 samples per iteration. Commit bfdd5bc (made all the way |
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* back in 2007) says that way is faster. |
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*/
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