mirror of https://github.com/FFmpeg/FFmpeg.git
parent
f3fb528cd5
commit
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11 changed files with 166 additions and 86 deletions
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/*
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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 "libavutil/float2half.c" |
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/*
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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 "libavutil/half2float.c" |
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/*
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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 "libavutil/float2half.h" |
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void ff_init_float2half_tables(Float2HalfTables *t) |
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{ |
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for (int i = 0; i < 256; i++) { |
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int e = i - 127; |
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if (e < -24) { // Very small numbers map to zero
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t->basetable[i|0x000] = 0x0000; |
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t->basetable[i|0x100] = 0x8000; |
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t->shifttable[i|0x000] = 24; |
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t->shifttable[i|0x100] = 24; |
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} else if (e < -14) { // Small numbers map to denorms
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t->basetable[i|0x000] = (0x0400>>(-e-14)); |
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t->basetable[i|0x100] = (0x0400>>(-e-14)) | 0x8000; |
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t->shifttable[i|0x000] = -e-1; |
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t->shifttable[i|0x100] = -e-1; |
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} else if (e <= 15) { // Normal numbers just lose precision
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t->basetable[i|0x000] = ((e + 15) << 10); |
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t->basetable[i|0x100] = ((e + 15) << 10) | 0x8000; |
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t->shifttable[i|0x000] = 13; |
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t->shifttable[i|0x100] = 13; |
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} else if (e < 128) { // Large numbers map to Infinity
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t->basetable[i|0x000] = 0x7C00; |
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t->basetable[i|0x100] = 0xFC00; |
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t->shifttable[i|0x000] = 24; |
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t->shifttable[i|0x100] = 24; |
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} else { // Infinity and NaN's stay Infinity and NaN's
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t->basetable[i|0x000] = 0x7C00; |
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t->basetable[i|0x100] = 0xFC00; |
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t->shifttable[i|0x000] = 13; |
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t->shifttable[i|0x100] = 13; |
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} |
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} |
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} |
@ -0,0 +1,63 @@ |
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/*
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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 "libavutil/half2float.h" |
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static uint32_t convertmantissa(uint32_t i) |
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{ |
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int32_t m = i << 13; // Zero pad mantissa bits
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int32_t e = 0; // Zero exponent
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while (!(m & 0x00800000)) { // While not normalized
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e -= 0x00800000; // Decrement exponent (1<<23)
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m <<= 1; // Shift mantissa
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} |
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m &= ~0x00800000; // Clear leading 1 bit
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e += 0x38800000; // Adjust bias ((127-14)<<23)
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return m | e; // Return combined number
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} |
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void ff_init_half2float_tables(Half2FloatTables *t) |
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{ |
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t->mantissatable[0] = 0; |
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for (int i = 1; i < 1024; i++) |
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t->mantissatable[i] = convertmantissa(i); |
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for (int i = 1024; i < 2048; i++) |
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t->mantissatable[i] = 0x38000000UL + ((i - 1024) << 13UL); |
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for (int i = 2048; i < 3072; i++) |
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t->mantissatable[i] = t->mantissatable[i - 1024] | 0x400000UL; |
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t->mantissatable[2048] = t->mantissatable[1024]; |
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t->exponenttable[0] = 0; |
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for (int i = 1; i < 31; i++) |
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t->exponenttable[i] = i << 23; |
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for (int i = 33; i < 63; i++) |
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t->exponenttable[i] = 0x80000000UL + ((i - 32) << 23UL); |
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t->exponenttable[31]= 0x47800000UL; |
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t->exponenttable[32]= 0x80000000UL; |
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t->exponenttable[63]= 0xC7800000UL; |
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t->offsettable[0] = 0; |
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for (int i = 1; i < 64; i++) |
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t->offsettable[i] = 1024; |
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t->offsettable[31] = 2048; |
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t->offsettable[32] = 0; |
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t->offsettable[63] = 2048; |
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} |
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