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976a8b2179
* qatar/master: (40 commits) H.264: template left MB handling H.264: faster fill_decode_caches H.264: faster write_back_* H.264: faster fill_filter_caches H.264: make filter_mb_fast support the case of unavailable top mb Do not include log.h in avutil.h Do not include pixfmt.h in avutil.h Do not include rational.h in avutil.h Do not include mathematics.h in avutil.h Do not include intfloat_readwrite.h in avutil.h Remove return statements following infinite loops without break RTSP: Doxygen comment cleanup doxygen: Escape '\' in Doxygen documentation. md5: cosmetics md5: use AV_WL32 to write result md5: add fate test md5: include correct headers md5: fix test program doxygen: Drop array size declarations from Doxygen parameter names. doxygen: Fix parameter names to match the function prototypes. ... Conflicts: libavcodec/x86/dsputil_mmx.c libavformat/flvenc.c libavformat/oggenc.c libavformat/wtv.c Merged-by: Michael Niedermayer <michaelni@gmx.at>
63 lines
1.9 KiB
C
63 lines
1.9 KiB
C
/*
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* Lagged Fibonacci PRNG
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* Copyright (c) 2008 Michael Niedermayer
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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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#ifndef AVUTIL_LFG_H
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#define AVUTIL_LFG_H
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typedef struct {
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unsigned int state[64];
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int index;
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} AVLFG;
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void av_lfg_init(AVLFG *c, unsigned int seed);
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/**
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* Get the next random unsigned 32-bit number using an ALFG.
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*
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* Please also consider a simple LCG like state= state*1664525+1013904223,
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* it may be good enough and faster for your specific use case.
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*/
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static inline unsigned int av_lfg_get(AVLFG *c){
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c->state[c->index & 63] = c->state[(c->index-24) & 63] + c->state[(c->index-55) & 63];
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return c->state[c->index++ & 63];
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}
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/**
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* Get the next random unsigned 32-bit number using a MLFG.
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*
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* Please also consider av_lfg_get() above, it is faster.
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*/
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static inline unsigned int av_mlfg_get(AVLFG *c){
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unsigned int a= c->state[(c->index-55) & 63];
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unsigned int b= c->state[(c->index-24) & 63];
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return c->state[c->index++ & 63] = 2*a*b+a+b;
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}
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/**
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* Get the next two numbers generated by a Box-Muller Gaussian
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* generator using the random numbers issued by lfg.
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*
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* @param out array where the two generated numbers are placed
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*/
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void av_bmg_get(AVLFG *lfg, double out[2]);
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#endif /* AVUTIL_LFG_H */
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