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- /*
- * dither.h
- *
- * Copyright (C) Aaron Holtzman - May 1999
- *
- * This file is part of ac3dec, a free Dolby AC-3 stream decoder.
- *
- * ac3dec is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2, or (at your option)
- * any later version.
- *
- * ac3dec is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with GNU Make; see the file COPYING. If not, write to
- * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
- *
- */
-
-
- extern uint_16 lfsr_state;
- extern const uint_16 dither_lut[256];
-
- static inline uint_16 dither_gen(void)
- {
- sint_16 state;
-
- state = dither_lut[lfsr_state >> 8] ^ (lfsr_state << 8);
-
- lfsr_state = (uint_16) state;
-
- return ((state * (sint_32) (0.707106 * 256.0))>>8);
- }
-