494 lines
12 KiB
C++
494 lines
12 KiB
C++
/*
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* Copyright (c) 2010 The VP8 project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license and patent
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* grant that can be found in the LICENSE file in the root of the source
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* tree. All contributing project authors may be found in the AUTHORS
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* file in the root of the source tree.
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*/
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/* Arithmetic bool coder with largish probability range.
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Timothy S Murphy 6 August 2004 */
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#include <assert.h>
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#include <math.h>
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#include "bool_coder.h"
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#if tim_vp8
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extern "C" {
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# include "VP8cx/treewriter.h"
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}
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#endif
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int_types::~int_types() {}
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void bool_coder_spec::check_prec() const {
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assert( w && (r==Up || w > 1) && w < 24 && (ebias || w < 17));
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}
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bool bool_coder_spec::float_init( uint Ebits, uint Mbits) {
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uint b = (ebits = Ebits) + (mbits = Mbits);
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if( b) {
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assert( ebits < 6 && w + mbits < 31);
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assert( ebits + mbits < sizeof(Index) * 8);
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ebias = (1 << ebits) + 1 + mbits;
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mmask = (1 << mbits) - 1;
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max_index = ( ( half_index = 1 << b ) << 1) - 1;
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} else {
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ebias = 0;
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max_index = 255;
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half_index = 128;
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}
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check_prec();
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return b? 1:0;
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}
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void bool_coder_spec::cost_init()
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{
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static cdouble c = -(1 << 20)/log( 2.);
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FILE *f = fopen( "costs.txt", "w");
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assert( f);
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assert( sizeof(int) >= 4); /* for C interface */
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assert( max_index <= 255); /* size of Ctbl */
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uint i = 0; do {
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cdouble p = ( *this)( (Index) i);
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Ctbl[i] = (uint32) ( log( p) * c);
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fprintf(
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f, "cost( %d -> %10.7f) = %10d = %12.5f bits\n",
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i, p, Ctbl[i], (double) Ctbl[i] / (1<<20)
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);
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} while( ++i <= max_index);
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fclose( f);
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}
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bool_coder_spec_explicit_table::bool_coder_spec_explicit_table(
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cuint16 tbl[256], Rounding rr, uint prec
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)
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: bool_coder_spec( prec, rr)
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{
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check_prec();
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uint i = 0;
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if( tbl)
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do { Ptbl[i] = tbl[i];} while( ++i < 256);
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else
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do { Ptbl[i] = i << 8;} while( ++i < 256);
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cost_init();
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}
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bool_coder_spec_exponential_table::bool_coder_spec_exponential_table(
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uint x, Rounding rr, uint prec
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)
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: bool_coder_spec( prec, rr)
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{
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assert( x > 1 && x <= 16);
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check_prec();
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Ptbl[128] = 32768u;
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Ptbl[0] = (uint16) pow( 2., 16. - x);
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--x;
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int i=1; do {
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cdouble d = pow( .5, 1. + (1. - i/128.)*x) * 65536.;
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uint16 v = (uint16) d;
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if( v < i)
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v = i;
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Ptbl[256-i] = (uint16) ( 65536U - (Ptbl[i] = v));
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} while( ++i < 128);
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cost_init();
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}
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bool_coder_spec::bool_coder_spec( FILE *fp) {
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fscanf( fp, "%d", &w);
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int v;
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fscanf( fp, "%d", &v);
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assert( 0 <= v && v <= 2);
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r = (Rounding) v;
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fscanf( fp, "%d", &ebits);
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fscanf( fp, "%d", &mbits);
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if( float_init( ebits, mbits))
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return;
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int i=0; do {
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uint v;
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fscanf( fp, "%d", &v);
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assert( 0 <=v && v <= 65535U);
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Ptbl[i] = v;
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} while( ++i < 256);
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cost_init();
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}
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void bool_coder_spec::dump( FILE *fp) const {
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fprintf( fp, "%d %d %d %d\n", w, (int) r, ebits, mbits);
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if( ebits || mbits)
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return;
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int i=0; do { fprintf( fp, "%d\n", Ptbl[i]);} while( ++i < 256);
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}
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vp8bc_index_t bool_coder_spec::operator()( double p) const
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{
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if( p <= 0.)
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return 0;
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if( p >= 1.)
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return max_index;
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if( ebias) {
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if( p > .5)
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return max_index - ( *this)( 1. - p);
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int e;
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uint m = (uint) ldexp( frexp( p, &e), mbits + 2);
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uint x = 1 << (mbits + 1);
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assert( x <= m && m < x<<1);
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if( (m = (m >> 1) + (m & 1)) >= x) {
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m = x >> 1;
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++e;
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}
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int y = 1 << ebits;
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if( (e += y) >= y)
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return half_index - 1;
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if( e < 0)
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return 0;
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return (Index) ( (e << mbits) + (m & mmask));
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}
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cuint16 v = (uint16) (p * 65536.);
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int i = 128;
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int j = 128;
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uint16 w;
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while( w = Ptbl[i], j >>= 1) {
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if( w < v)
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i += j;
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else if( w == v)
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return (uchar) i;
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else
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i -= j;
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}
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if( w > v) {
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cuint16 x = Ptbl[i-1];
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if( v <= x || w - v > v - x)
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--i;
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} else if( w < v && i < 255) {
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cuint16 x = Ptbl[i+1];
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if( x <= v || x - v < v - w)
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++i;
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}
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return (Index) i;
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}
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double bool_coder_spec::operator()( Index i) const {
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if( !ebias)
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return Ptbl[i]/65536.;
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if( i >= half_index)
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return 1. - ( *this)( (Index) (max_index - i));
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return ldexp( (double)mantissa( i), - (int) exponent( i));
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}
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void bool_writer::carry() {
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uchar *p = B;
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assert( p > Bstart);
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while( *--p == 255) { assert( p > Bstart); *p = 0;}
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++*p;
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}
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bool_writer::bool_writer( c_spec& s, uchar *Dest, size_t Len)
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: bool_coder( s),
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Bstart( Dest),
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Bend( Len? Dest+Len : 0),
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B( Dest)
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{
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assert( Dest);
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reset();
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}
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bool_writer::~bool_writer() { flush();}
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#if 1
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extern "C" { int bc_v = 0;}
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#else
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# define bc_v 0
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#endif
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void bool_writer::raw( bool value, uint32 s) {
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uint32 L = Low;
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assert( Range >= min_range && Range <= spec.max_range());
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assert( !is_toast && s && s < Range);
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if( bc_v) printf(
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"Writing a %d, B %x Low %x Range %x s %x blag %d ...\n",
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value? 1:0, B-Bstart, Low, Range, s, bit_lag
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);
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if( value) {
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L += s;
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s = Range - s;
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} else
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s -= rinc;
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if( s < min_range) {
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int ct = bit_lag; do {
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if( !--ct) {
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ct = 8;
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if( L & (1 << 31))
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carry();
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assert( !Bend || B < Bend);
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*B++ = (uchar) (L >> 23);
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L &= (1<<23) - 1;
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}
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} while( L += L, (s += s + rinc) < min_range);
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bit_lag = ct;
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}
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Low = L;
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Range = s;
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if( bc_v)
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printf(
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"...done, B %x Low %x Range %x blag %d \n",
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B-Bstart, Low, Range, bit_lag
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);
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}
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bool_writer& bool_writer::flush() {
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if( is_toast)
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return *this;
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int b = bit_lag;
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uint32 L = Low;
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assert( b);
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if( L & (1 << (32 - b)))
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carry();
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L <<= b & 7;
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b >>= 3;
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while( --b >= 0)
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L <<= 8;
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b = 4;
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assert( !Bend || B + 4 <= Bend);
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do {
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*B++ = (uchar) (L >> 24);
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L <<= 8;
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} while( --b);
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is_toast = 1;
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return *this;
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}
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bool_reader::bool_reader( c_spec& s, cuchar *src, size_t Len)
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: bool_coder( s),
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Bstart( src),
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B( src),
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Bend( Len? src+Len : 0),
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shf( 32 - s.w),
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bct( 8)
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{
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int i = 4; do { Low <<= 8; Low |= *B++;} while( --i);
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}
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bool bool_reader::raw( uint32 s) {
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bool val = 0;
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uint32 L = Low;
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cuint32 S = s << shf;
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assert( Range >= min_range && Range <= spec.max_range());
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assert( s && s < Range && (L >> shf) < Range);
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if( bc_v)
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printf(
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"Reading, B %x Low %x Range %x s %x bct %d ...\n",
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B-Bstart, Low, Range, s, bct
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);
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if( L >= S) {
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L -= S;
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s = Range - s;
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assert( L < (s << shf));
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val = 1;
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} else
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s -= rinc;
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if( s < min_range) {
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int ct = bct;
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do {
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assert( ~L & (1 << 31));
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L += L;
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if( !--ct) {
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ct = 8;
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if( !Bend || B < Bend)
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L |= *B++;
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}
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} while( (s += s + rinc) < min_range);
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bct = ct;
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}
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Low = L;
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Range = s;
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if( bc_v)
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printf(
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"...done, val %d B %x Low %x Range %x bct %d\n",
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val? 1:0, B-Bstart, Low, Range, bct
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);
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return val;
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}
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/* C interfaces */
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// spec interface
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struct NS : bool_coder_namespace {
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static Rounding r( vp8bc_c_prec *p, Rounding rr =down_full) {
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return p? (Rounding) p->r : rr;
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}
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};
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bool_coder_spec *vp8bc_vp6spec() {
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return new bool_coder_spec_explicit_table( 0, bool_coder_namespace::Down, 8);
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}
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bool_coder_spec *vp8bc_float_spec(
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unsigned int Ebits, unsigned int Mbits, vp8bc_c_prec *p
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) {
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return new bool_coder_spec_float( Ebits, Mbits, NS::r( p), p? p->prec : 12);
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}
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bool_coder_spec *vp8bc_literal_spec(
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const unsigned short m[256], vp8bc_c_prec *p
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) {
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return new bool_coder_spec_explicit_table( m, NS::r( p), p? p->prec : 16);
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}
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bool_coder_spec *vp8bc_exponential_spec( unsigned int x, vp8bc_c_prec *p)
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{
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return new bool_coder_spec_exponential_table( x, NS::r( p), p? p->prec : 16);
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}
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bool_coder_spec *vp8bc_spec_from_file( FILE *fp) {
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return new bool_coder_spec( fp);
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}
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void vp8bc_destroy_spec( c_bool_coder_spec *p) { delete p;}
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void vp8bc_spec_to_file( c_bool_coder_spec *p, FILE *fp) { p->dump( fp);}
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vp8bc_index_t vp8bc_index( c_bool_coder_spec *p, double x) {
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return ( *p)( x);
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}
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vp8bc_index_t vp8bc_index_from_counts(
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c_bool_coder_spec *p, unsigned int L, unsigned int R
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) {
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return ( *p)( (R += L)? (double) L/R : .5);
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}
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double vp8bc_probability( c_bool_coder_spec *p, vp8bc_index_t i) {
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return ( *p)( i);
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}
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vp8bc_index_t vp8bc_complement( c_bool_coder_spec *p, vp8bc_index_t i) {
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return p->complement( i);
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}
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unsigned int vp8bc_cost_zero( c_bool_coder_spec *p, vp8bc_index_t i) {
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return p->cost_zero( i);
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}
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unsigned int vp8bc_cost_one( c_bool_coder_spec *p, vp8bc_index_t i) {
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return p->cost_one( i);
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}
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unsigned int vp8bc_cost_bit( c_bool_coder_spec *p, vp8bc_index_t i, int v) {
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return p->cost_bit( i, v);
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}
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#if tim_vp8
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extern "C" int tok_verbose;
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# define dbg_l 1000000
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static vp8bc_index_t dbg_i [dbg_l];
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static char dbg_v [dbg_l];
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static size_t dbg_w = 0, dbg_r = 0;
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#endif
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// writer interface
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bool_writer *vp8bc_create_writer(
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c_bool_coder_spec *p, unsigned char *D, size_t L
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) {
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return new bool_writer( *p, D, L);
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}
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size_t vp8bc_destroy_writer( bool_writer *p) {
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const size_t s = p->flush().bytes_written();
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delete p;
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return s;
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}
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void vp8bc_write_bool( bool_writer *p, int v, vp8bc_index_t i)
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{
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# if tim_vp8
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// bc_v = dbg_w < 10;
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if( bc_v = tok_verbose)
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printf( " writing %d at prob %d\n", v? 1:0, i);
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accum_entropy_bc( &p->Spec(), i, v);
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( *p)( i, (bool) v);
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if( dbg_w < dbg_l) {
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dbg_i [dbg_w] = i;
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dbg_v [dbg_w++] = v? 1:0;
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}
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# else
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( *p)( i, (bool) v);
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# endif
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}
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void vp8bc_write_bits( bool_writer *p, unsigned int v, int n)
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{
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# if tim_vp8
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{
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c_bool_coder_spec * const s = & p->Spec();
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const vp8bc_index_t i = s->half_index();
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int m = n;
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while( --m >= 0)
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accum_entropy_bc( s, i, (v>>m) & 1);
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}
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# endif
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p->write_bits( n, v);
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}
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c_bool_coder_spec *vp8bc_writer_spec( c_bool_writer *w) { return & w->Spec();}
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// reader interface
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bool_reader *vp8bc_create_reader(
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c_bool_coder_spec *p, const unsigned char *S, size_t L
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) {
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return new bool_reader( *p, S, L);
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}
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void vp8bc_destroy_reader( bool_reader * p) { delete p;}
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int vp8bc_read_bool( bool_reader *p, vp8bc_index_t i)
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{
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# if tim_vp8
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// bc_v = dbg_r < 10;
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bc_v = tok_verbose;
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const int v = ( *p)( i)? 1:0;
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if( tok_verbose)
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printf( " reading %d at prob %d\n", v, i);
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if( dbg_r < dbg_l) {
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assert( dbg_r <= dbg_w);
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if( i != dbg_i[dbg_r] || v != dbg_v[dbg_r]) {
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printf(
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"Position %d: INCORRECTLY READING %d prob %d, wrote %d prob %d\n",
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dbg_r, v, i, dbg_v[dbg_r], dbg_i[dbg_r]
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);
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}
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++dbg_r;
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}
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return v;
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# else
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return ( *p)( i)? 1:0;
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# endif
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}
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unsigned int vp8bc_read_bits( bool_reader *p, int n) { return p->read_bits( n);}
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c_bool_coder_spec *vp8bc_reader_spec( c_bool_reader *r) { return & r->Spec();}
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#undef bc_v
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