mirror of https://git.ffmpeg.org/ffmpeg.git
Replace MPEG group reference DCT implementation by newly rewritten version.
patch by Dylan Yudaken, dyudaken gmail com Originally committed as revision 18274 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Dylan Yudaken
Diego Biurrun
parent
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commit
3ba153f8da
4
LICENSE
4
LICENSE
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@ -31,7 +31,3 @@ There are a handful of files under other licensing terms, namely:
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* The files libavcodec/jfdctfst.c, libavcodec/jfdctint.c, libavcodec/jrevdct.c
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are taken from libjpeg, see the top of the files for licensing details.
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* The file libavcodec/fdctref.c is copyrighted by the MPEG Software Simulation
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Group with all rights reserved. It is only used to create a DCT test program
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and not compiled into libavcodec.
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1
doc/TODO
1
doc/TODO
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@ -81,7 +81,6 @@ unassigned TODO: (unordered)
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- add support for using mplayers video filters to ffmpeg
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- H264 encoder
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- per MB ratecontrol (so VCD and such do work better)
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- replace/rewrite libavcodec/fdctref.c
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- write a script which iteratively changes all functions between always_inline and noinline and benchmarks the result to find the best set of inlined functions
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- convert all the non SIMD asm into small asm vs. C testcases and submit them to the gcc devels so they can improve gcc
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- generic audio mixing API
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@ -541,4 +541,4 @@ DIRS = alpha arm bfin mlib ppc ps2 sh4 sparc x86
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include $(SUBDIR)../subdir.mak
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$(SUBDIR)dct-test$(EXESUF): $(SUBDIR)fdctref.o $(SUBDIR)aandcttab.o
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$(SUBDIR)dct-test$(EXESUF): $(SUBDIR)dctref.o $(SUBDIR)aandcttab.o
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@ -1,157 +0,0 @@
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/**
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* @file libavcodec/fdctref.c
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* forward discrete cosine transform, double precision.
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*/
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/* Copyright (C) 1996, MPEG Software Simulation Group. All Rights Reserved. */
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/*
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* Disclaimer of Warranty
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*
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* These software programs are available to the user without any license fee or
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* royalty on an "as is" basis. The MPEG Software Simulation Group disclaims
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* any and all warranties, whether express, implied, or statuary, including any
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* implied warranties or merchantability or of fitness for a particular
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* purpose. In no event shall the copyright-holder be liable for any
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* incidental, punitive, or consequential damages of any kind whatsoever
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* arising from the use of these programs.
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*
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* This disclaimer of warranty extends to the user of these programs and user's
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* customers, employees, agents, transferees, successors, and assigns.
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*
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* The MPEG Software Simulation Group does not represent or warrant that the
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* programs furnished hereunder are free of infringement of any third-party
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* patents.
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*
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* Commercial implementations of MPEG-1 and MPEG-2 video, including shareware,
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* are subject to royalty fees to patent holders. Many of these patents are
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* general enough such that they are unavoidable regardless of implementation
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* design.
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*/
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#include <math.h>
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#ifndef PI
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# ifdef M_PI
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# define PI M_PI
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# else
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# define PI 3.14159265358979323846
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# endif
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#endif
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/* global declarations */
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void ff_ref_dct_init (void);
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void ff_ref_fdct (short *block);
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/* private data */
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static double c[8][8]; /* transform coefficients */
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void ff_ref_dct_init(void)
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{
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int i, j;
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double s;
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for (i=0; i<8; i++)
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{
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s = (i==0) ? sqrt(0.125) : 0.5;
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for (j=0; j<8; j++)
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c[i][j] = s * cos((PI/8.0)*i*(j+0.5));
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}
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}
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void ff_ref_fdct(block)
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short *block;
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{
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register int i, j;
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double s;
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double tmp[64];
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for(i = 0; i < 8; i++)
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for(j = 0; j < 8; j++)
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{
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s = 0.0;
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/*
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* for(k = 0; k < 8; k++)
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* s += c[j][k] * block[8 * i + k];
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*/
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s += c[j][0] * block[8 * i + 0];
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s += c[j][1] * block[8 * i + 1];
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s += c[j][2] * block[8 * i + 2];
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s += c[j][3] * block[8 * i + 3];
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s += c[j][4] * block[8 * i + 4];
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s += c[j][5] * block[8 * i + 5];
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s += c[j][6] * block[8 * i + 6];
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s += c[j][7] * block[8 * i + 7];
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tmp[8 * i + j] = s;
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}
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for(j = 0; j < 8; j++)
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for(i = 0; i < 8; i++)
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{
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s = 0.0;
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/*
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* for(k = 0; k < 8; k++)
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* s += c[i][k] * tmp[8 * k + j];
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*/
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s += c[i][0] * tmp[8 * 0 + j];
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s += c[i][1] * tmp[8 * 1 + j];
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s += c[i][2] * tmp[8 * 2 + j];
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s += c[i][3] * tmp[8 * 3 + j];
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s += c[i][4] * tmp[8 * 4 + j];
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s += c[i][5] * tmp[8 * 5 + j];
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s += c[i][6] * tmp[8 * 6 + j];
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s += c[i][7] * tmp[8 * 7 + j];
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s*=8.0;
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block[8 * i + j] = (short)floor(s + 0.499999);
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/*
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* reason for adding 0.499999 instead of 0.5:
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* s is quite often x.5 (at least for i and/or j = 0 or 4)
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* and setting the rounding threshold exactly to 0.5 leads to an
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* extremely high arithmetic implementation dependency of the result;
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* s being between x.5 and x.500001 (which is now incorrectly rounded
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* downwards instead of upwards) is assumed to occur less often
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* (if at all)
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*/
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}
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}
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/* perform IDCT matrix multiply for 8x8 coefficient block */
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void ff_ref_idct(block)
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short *block;
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{
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int i, j, k, v;
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double partial_product;
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double tmp[64];
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for (i=0; i<8; i++)
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for (j=0; j<8; j++)
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{
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partial_product = 0.0;
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for (k=0; k<8; k++)
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partial_product+= c[k][j]*block[8*i+k];
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tmp[8*i+j] = partial_product;
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}
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/* Transpose operation is integrated into address mapping by switching
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loop order of i and j */
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for (j=0; j<8; j++)
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for (i=0; i<8; i++)
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{
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partial_product = 0.0;
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for (k=0; k<8; k++)
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partial_product+= c[k][i]*tmp[8*k+j];
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v = (int) floor(partial_product+0.5);
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block[8*i+j] = v;
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}
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}
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