491 lines
18 KiB
C
491 lines
18 KiB
C
/*****************************************************************************
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* rdo.c: h264 encoder library (rate-distortion optimization)
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*****************************************************************************
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* Copyright (C) 2005 x264 project
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*
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* Authors: Loren Merritt <lorenm@u.washington.edu>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program 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
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
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*****************************************************************************/
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/* duplicate all the writer functions, just calculating bit cost
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* instead of writing the bitstream.
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* TODO: use these for fast 1st pass too. */
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//#include <stdint.h>
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//#include <x264.h>
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#define RDO_SKIP_BS
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/* CAVLC: produces exactly the same bit count as a normal encode */
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/* this probably still leaves some unnecessary computations */
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/*
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#define bs_write1(s,v) ((s)->i_bits_encoded += 1)
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#define bs_write(s,n,v) ((s)->i_bits_encoded += (n))
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#define bs_write_ue(s,v) ((s)->i_bits_encoded += bs_size_ue(v))
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#define bs_write_se(s,v) ((s)->i_bits_encoded += bs_size_se(v))
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#define bs_write_te(s,v,l) ((s)->i_bits_encoded += bs_size_te(v,l))
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*/
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#define x264_macroblock_write_cavlc x264_macroblock_size_cavlc
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#include "cavlc.c"
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/* CABAC: not exactly the same. x264_cabac_size_decision() keeps track of
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* fractional bits, but only finite precision. */
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#define x264_cabac_encode_decision(c,x,v) x264_cabac_size_decision(c,x,v)
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#define x264_cabac_encode_terminal(c,v) x264_cabac_size_decision(c,276,v)
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#define x264_cabac_encode_bypass(c,v) ((c)->f8_bits_encoded += 256)
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#define x264_cabac_encode_flush(c)
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#define x264_macroblock_write_cabac x264_macroblock_size_cabac
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#define x264_cabac_mb_skip x264_cabac_mb_size_skip_unused
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#include "cabac.c"
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static int ssd_mb( x264_t *h )
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{
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return h->pixf.ssd[PIXEL_16x16]( h->mb.pic.p_fenc[0], FENC_STRIDE,
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h->mb.pic.p_fdec[0], FDEC_STRIDE )
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+ h->pixf.ssd[PIXEL_8x8]( h->mb.pic.p_fenc[1], FENC_STRIDE,
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h->mb.pic.p_fdec[1], FDEC_STRIDE )
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+ h->pixf.ssd[PIXEL_8x8]( h->mb.pic.p_fenc[2], FENC_STRIDE,
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h->mb.pic.p_fdec[2], FDEC_STRIDE );
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}
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static int ssd_plane( x264_t *h, int size, int p, int x, int y )
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{
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return h->pixf.ssd[size]( h->mb.pic.p_fenc[p] + x+y*FENC_STRIDE, FENC_STRIDE,
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h->mb.pic.p_fdec[p] + x+y*FDEC_STRIDE, FDEC_STRIDE );
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}
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static int x264_rd_cost_mb( x264_t *h, int i_lambda2 )
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{
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int b_transform_bak = h->mb.b_transform_8x8;
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int i_ssd;
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int i_bits;
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x264_macroblock_encode( h );
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i_ssd = ssd_mb( h );
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if( IS_SKIP( h->mb.i_type ) )
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{
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i_bits = 1 * i_lambda2;
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}
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else if( h->param.b_cabac )
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{
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x264_cabac_t cabac_tmp = h->cabac;
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cabac_tmp.f8_bits_encoded = 0;
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x264_macroblock_size_cabac( h, &cabac_tmp );
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i_bits = ( cabac_tmp.f8_bits_encoded * i_lambda2 + 128 ) >> 8;
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}
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else
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{
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bs_t bs_tmp = h->out.bs;
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bs_tmp.i_bits_encoded = 0;
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x264_macroblock_size_cavlc( h, &bs_tmp );
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i_bits = bs_tmp.i_bits_encoded * i_lambda2;
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}
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h->mb.b_transform_8x8 = b_transform_bak;
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return i_ssd + i_bits;
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}
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int x264_rd_cost_part( x264_t *h, int i_lambda2, int i8, int i_pixel )
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{
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int i_ssd, i_bits;
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if( i_pixel == PIXEL_16x16 )
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{
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int type_bak = h->mb.i_type;
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int i_cost = x264_rd_cost_mb( h, i_lambda2 );
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h->mb.i_type = type_bak;
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return i_cost;
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}
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x264_macroblock_encode_p8x8( h, i8 );
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if( i_pixel == PIXEL_16x8 )
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x264_macroblock_encode_p8x8( h, i8+1 );
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if( i_pixel == PIXEL_8x16 )
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x264_macroblock_encode_p8x8( h, i8+2 );
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i_ssd = ssd_plane( h, i_pixel, 0, (i8&1)*8, (i8>>1)*8 )
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+ ssd_plane( h, i_pixel+3, 1, (i8&1)*4, (i8>>1)*4 )
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+ ssd_plane( h, i_pixel+3, 2, (i8&1)*4, (i8>>1)*4 );
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if( h->param.b_cabac )
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{
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x264_cabac_t cabac_tmp = h->cabac;
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cabac_tmp.f8_bits_encoded = 0;
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x264_partition_size_cabac( h, &cabac_tmp, i8, i_pixel );
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i_bits = ( cabac_tmp.f8_bits_encoded * i_lambda2 + 128 ) >> 8;
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}
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else
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{
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i_bits = x264_partition_size_cavlc( h, i8, i_pixel ) * i_lambda2;
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}
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return i_ssd + i_bits;
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}
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int x264_rd_cost_i8x8( x264_t *h, int i_lambda2, int i8, int i_mode )
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{
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int i_ssd, i_bits;
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x264_mb_encode_i8x8( h, i8, h->mb.i_qp );
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i_ssd = ssd_plane( h, PIXEL_8x8, 0, (i8&1)*8, (i8>>1)*8 );
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if( h->param.b_cabac )
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{
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x264_cabac_t cabac_tmp = h->cabac;
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cabac_tmp.f8_bits_encoded = 0;
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x264_partition_i8x8_size_cabac( h, &cabac_tmp, i8, i_mode );
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i_bits = ( cabac_tmp.f8_bits_encoded * i_lambda2 + 128 ) >> 8;
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}
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else
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{
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i_bits = x264_partition_i8x8_size_cavlc( h, i8, i_mode ) * i_lambda2;
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}
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return i_ssd + i_bits;
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}
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int x264_rd_cost_i4x4( x264_t *h, int i_lambda2, int i4, int i_mode )
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{
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int i_ssd, i_bits;
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x264_mb_encode_i4x4( h, i4, h->mb.i_qp );
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i_ssd = ssd_plane( h, PIXEL_4x4, 0, block_idx_x[i4]*4, block_idx_y[i4]*4 );
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if( h->param.b_cabac )
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{
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x264_cabac_t cabac_tmp = h->cabac;
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cabac_tmp.f8_bits_encoded = 0;
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x264_partition_i4x4_size_cabac( h, &cabac_tmp, i4, i_mode );
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i_bits = ( cabac_tmp.f8_bits_encoded * i_lambda2 + 128 ) >> 8;
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}
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else
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{
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i_bits = x264_partition_i4x4_size_cavlc( h, i4, i_mode ) * i_lambda2;
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}
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return i_ssd + i_bits;
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}
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/****************************************************************************
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* Trellis RD quantization
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****************************************************************************/
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#define TRELLIS_SCORE_MAX ((uint64_t)1<<50)
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#define CABAC_SIZE_BITS 8
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#define SSD_WEIGHT_BITS 5
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#define LAMBDA_BITS 4
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/* precalculate the cost of coding abs_level_m1 */
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static int cabac_prefix_transition[15][128];
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static int cabac_prefix_size[15][128];
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void x264_rdo_init( )
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{
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int i_prefix;
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int i_ctx;
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for( i_prefix = 0; i_prefix < 15; i_prefix++ )
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{
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for( i_ctx = 0; i_ctx < 128; i_ctx++ )
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{
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int f8_bits = 0;
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uint8_t ctx = i_ctx;
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int i;
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for( i = 1; i < i_prefix; i++ )
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f8_bits += x264_cabac_size_decision2( &ctx, 1 );
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if( i_prefix > 0 && i_prefix < 14 )
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f8_bits += x264_cabac_size_decision2( &ctx, 0 );
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f8_bits += 1 << CABAC_SIZE_BITS; //sign
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cabac_prefix_size[i_prefix][i_ctx] = f8_bits;
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cabac_prefix_transition[i_prefix][i_ctx] = ctx;
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}
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}
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}
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// node ctx: 0..3: abslevel1 (with abslevelgt1 == 0).
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// 4..7: abslevelgt1 + 3 (and abslevel1 doesn't matter).
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/* map node ctx => cabac ctx for level=1 */
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static const int coeff_abs_level1_ctx[8] = { 1, 2, 3, 4, 0, 0, 0, 0 };
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/* map node ctx => cabac ctx for level>1 */
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static const int coeff_abs_levelgt1_ctx[8] = { 5, 5, 5, 5, 6, 7, 8, 9 };
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static const int coeff_abs_level_transition[2][8] = {
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/* update node.ctx after coding a level=1 */
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{ 1, 2, 3, 3, 4, 5, 6, 7 },
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/* update node.ctx after coding a level>1 */
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{ 4, 4, 4, 4, 5, 6, 7, 7 }
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};
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static const int lambda2_tab[6] = { 1024, 1290, 1625, 2048, 2580, 3251 };
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typedef struct {
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uint64_t score;
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int level_idx; // index into level_tree[]
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uint8_t cabac_state[10]; //just the contexts relevant to coding abs_level_m1
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} trellis_node_t;
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// TODO:
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// support chroma and i16x16 DC
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// save cabac state between blocks?
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// use trellis' RD score instead of x264_mb_decimate_score?
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// code 8x8 sig/last flags forwards with deadzone and save the contexts at
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// each position?
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// change weights when using CQMs?
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// possible optimizations:
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// make scores fit in 32bit
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// save quantized coefs during rd, to avoid a duplicate trellis in the final encode
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// if trellissing all MBRD modes, finish SSD calculation so we can skip all of
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// the normal dequant/idct/ssd/cabac
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// the unquant_mf here is not the same as dequant_mf:
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// in normal operation (dct->quant->dequant->idct) the dct and idct are not
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// normalized. quant/dequant absorb those scaling factors.
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// in this function, we just do (quant->unquant) and want the output to be
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// comparable to the input. so unquant is the direct inverse of quant,
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// and uses the dct scaling factors, not the idct ones.
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static void quant_trellis_cabac( x264_t *h, int16_t *dct,
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const int *quant_mf, const int *unquant_mf,
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const int *coef_weight, const int *zigzag,
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int i_ctxBlockCat, int i_qbits, int i_lambda2, int b_ac, int i_coefs )
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{
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int abs_coefs[64], signs[64];
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trellis_node_t nodes[2][8];
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trellis_node_t *nodes_cur = nodes[0];
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trellis_node_t *nodes_prev = nodes[1];
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trellis_node_t *bnode;
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uint8_t cabac_state_sig[64];
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uint8_t cabac_state_last[64];
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const int b_interlaced = h->mb.b_interlaced;
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const int f = 1 << (i_qbits-1); // no deadzone
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int i_last_nnz = -1;
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int i, j;
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// (# of coefs) * (# of ctx) * (# of levels tried) = 1024
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// we don't need to keep all of those: (# of coefs) * (# of ctx) would be enough,
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// but it takes more time to remove dead states than you gain in reduced memory.
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struct {
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uint16_t abs_level;
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uint16_t next;
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} level_tree[64*8*2];
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int i_levels_used = 1;
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/* init coefs */
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for( i = b_ac; i < i_coefs; i++ )
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{
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int coef = dct[zigzag[i]];
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abs_coefs[i] = abs(coef);
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signs[i] = coef < 0 ? -1 : 1;
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if( f <= abs_coefs[i] * quant_mf[zigzag[i]] )
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i_last_nnz = i;
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}
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if( i_last_nnz == -1 )
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{
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memset( dct, 0, i_coefs * sizeof(*dct) );
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return;
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}
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/* init trellis */
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for( i = 1; i < 8; i++ )
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nodes_cur[i].score = TRELLIS_SCORE_MAX;
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nodes_cur[0].score = 0;
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nodes_cur[0].level_idx = 0;
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level_tree[0].abs_level = 0;
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level_tree[0].next = 0;
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// coefs are processed in reverse order, because that's how the abs value is coded.
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// last_coef and significant_coef flags are normally coded in forward order, but
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// we have to reverse them to match the levels.
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// in 4x4 blocks, last_coef and significant_coef use a separate context for each
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// position, so the order doesn't matter, and we don't even have to update their contexts.
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// in 8x8 blocks, some positions share contexts, so we'll just have to hope that
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// cabac isn't too sensitive.
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if( i_coefs == 64 )
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{
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const uint8_t *ctx_sig = &h->cabac.state[ significant_coeff_flag_offset[b_interlaced][i_ctxBlockCat] ];
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const uint8_t *ctx_last = &h->cabac.state[ last_coeff_flag_offset[b_interlaced][i_ctxBlockCat] ];
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for( i = 0; i < 63; i++ )
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{
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cabac_state_sig[i] = ctx_sig[ significant_coeff_flag_offset_8x8[b_interlaced][i] ];
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cabac_state_last[i] = ctx_last[ last_coeff_flag_offset_8x8[i] ];
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}
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}
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else
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{
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memcpy( cabac_state_sig, &h->cabac.state[ significant_coeff_flag_offset[b_interlaced][i_ctxBlockCat] ], 15 );
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memcpy( cabac_state_last, &h->cabac.state[ last_coeff_flag_offset[b_interlaced][i_ctxBlockCat] ], 15 );
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}
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memcpy( nodes_cur[0].cabac_state, &h->cabac.state[ coeff_abs_level_m1_offset[i_ctxBlockCat] ], 10 );
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for( i = i_last_nnz; i >= b_ac; i-- )
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{
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int i_coef = abs_coefs[i];
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int q = ( f + i_coef * quant_mf[zigzag[i]] ) >> i_qbits;
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int abs_level;
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int cost_sig[2], cost_last[2];
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trellis_node_t n;
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// skip 0s: this doesn't affect the output, but saves some unnecessary computation.
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if( q == 0 )
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{
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// no need to calculate ssd of 0s: it's the same in all nodes.
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// no need to modify level_tree for ctx=0: it starts with an infinite loop of 0s.
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const int cost_sig0 = x264_cabac_size_decision_noup( &cabac_state_sig[i], 0 )
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* i_lambda2 >> ( CABAC_SIZE_BITS - LAMBDA_BITS );
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for( j = 1; j < 8; j++ )
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{
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if( nodes_cur[j].score != TRELLIS_SCORE_MAX )
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{
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#define SET_LEVEL(n,l) \
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level_tree[i_levels_used].abs_level = l; \
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level_tree[i_levels_used].next = n.level_idx; \
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n.level_idx = i_levels_used; \
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i_levels_used++;
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SET_LEVEL( nodes_cur[j], 0 );
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nodes_cur[j].score += cost_sig0;
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}
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}
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continue;
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}
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XCHG( trellis_node_t*, nodes_cur, nodes_prev );
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for( j = 0; j < 8; j++ )
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nodes_cur[j].score = TRELLIS_SCORE_MAX;
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if( i < i_coefs-1 )
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{
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cost_sig[0] = x264_cabac_size_decision_noup( &cabac_state_sig[i], 0 );
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cost_sig[1] = x264_cabac_size_decision_noup( &cabac_state_sig[i], 1 );
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cost_last[0] = x264_cabac_size_decision_noup( &cabac_state_last[i], 0 );
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cost_last[1] = x264_cabac_size_decision_noup( &cabac_state_last[i], 1 );
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}
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else
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{
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cost_sig[0] = cost_sig[1] = 0;
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cost_last[0] = cost_last[1] = 0;
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}
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// there are a few cases where increasing the coeff magnitude helps,
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// but it's only around .003 dB, and skipping them ~doubles the speed of trellis.
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// could also try q-2: that sometimes helps, but also sometimes decimates blocks
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// that are better left coded, especially at QP > 40.
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for( abs_level = q; abs_level >= q-1; abs_level-- )
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{
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int d = i_coef - ((unquant_mf[zigzag[i]] * abs_level + 128) >> 8);
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uint64_t ssd = (int64_t)d*d * coef_weight[i];
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for( j = 0; j < 8; j++ )
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{
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int node_ctx = j;
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if( nodes_prev[j].score == TRELLIS_SCORE_MAX )
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continue;
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n = nodes_prev[j];
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/* code the proposed level, and count how much entropy it would take */
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if( abs_level || node_ctx )
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{
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unsigned f8_bits = cost_sig[ abs_level != 0 ];
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if( abs_level )
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{
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const int i_prefix = X264_MIN( abs_level - 1, 14 );
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f8_bits += cost_last[ node_ctx == 0 ];
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f8_bits += x264_cabac_size_decision2( &n.cabac_state[coeff_abs_level1_ctx[node_ctx]], i_prefix > 0 );
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if( i_prefix > 0 )
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{
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uint8_t *ctx = &n.cabac_state[coeff_abs_levelgt1_ctx[node_ctx]];
|
|
f8_bits += cabac_prefix_size[i_prefix][*ctx];
|
|
*ctx = cabac_prefix_transition[i_prefix][*ctx];
|
|
if( abs_level >= 15 )
|
|
f8_bits += bs_size_ue( abs_level - 15 ) << CABAC_SIZE_BITS;
|
|
node_ctx = coeff_abs_level_transition[1][node_ctx];
|
|
}
|
|
else
|
|
{
|
|
f8_bits += 1 << CABAC_SIZE_BITS;
|
|
node_ctx = coeff_abs_level_transition[0][node_ctx];
|
|
}
|
|
}
|
|
n.score += (uint64_t)f8_bits * i_lambda2 >> ( CABAC_SIZE_BITS - LAMBDA_BITS );
|
|
}
|
|
|
|
n.score += ssd;
|
|
|
|
/* save the node if it's better than any existing node with the same cabac ctx */
|
|
if( n.score < nodes_cur[node_ctx].score )
|
|
{
|
|
SET_LEVEL( n, abs_level );
|
|
nodes_cur[node_ctx] = n;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* output levels from the best path through the trellis */
|
|
bnode = &nodes_cur[0];
|
|
for( j = 1; j < 8; j++ )
|
|
if( nodes_cur[j].score < bnode->score )
|
|
bnode = &nodes_cur[j];
|
|
|
|
j = bnode->level_idx;
|
|
for( i = b_ac; i < i_coefs; i++ )
|
|
{
|
|
dct[zigzag[i]] = level_tree[j].abs_level * signs[i];
|
|
j = level_tree[j].next;
|
|
}
|
|
}
|
|
|
|
|
|
void x264_quant_4x4_trellis( x264_t *h, int16_t dct[4][4], int i_quant_cat,
|
|
int i_qp, int i_ctxBlockCat, int b_intra )
|
|
{
|
|
const int i_qbits = i_qp / 6;
|
|
const int i_mf = i_qp % 6;
|
|
const int b_ac = (i_ctxBlockCat == DCT_LUMA_AC);
|
|
/* should the lambdas be different? I'm just matching the behaviour of deadzone quant. */
|
|
const int i_lambda_mult = b_intra ? 65 : 85;
|
|
const int i_lambda2 = ((lambda2_tab[i_mf] * i_lambda_mult*i_lambda_mult / 10000)
|
|
<< (2*i_qbits)) >> LAMBDA_BITS;
|
|
|
|
quant_trellis_cabac( h, (int16_t*)dct,
|
|
(int*)h->quant4_mf[i_quant_cat][i_mf], h->unquant4_mf[i_quant_cat][i_qp],
|
|
x264_dct4_weight2_zigzag[h->mb.b_interlaced],
|
|
x264_zigzag_scan4[h->mb.b_interlaced],
|
|
i_ctxBlockCat, 15+i_qbits, i_lambda2, b_ac, 16 );
|
|
}
|
|
|
|
|
|
void x264_quant_8x8_trellis( x264_t *h, int16_t dct[8][8], int i_quant_cat,
|
|
int i_qp, int b_intra )
|
|
{
|
|
const int i_qbits = i_qp / 6;
|
|
const int i_mf = i_qp % 6;
|
|
const int i_lambda_mult = b_intra ? 65 : 85;
|
|
const int i_lambda2 = ((lambda2_tab[i_mf] * i_lambda_mult*i_lambda_mult / 10000)
|
|
<< (2*i_qbits)) >> LAMBDA_BITS;
|
|
|
|
quant_trellis_cabac( h, (int16_t*)dct,
|
|
(int*)h->quant8_mf[i_quant_cat][i_mf], h->unquant8_mf[i_quant_cat][i_qp],
|
|
x264_dct8_weight2_zigzag[h->mb.b_interlaced],
|
|
x264_zigzag_scan8[h->mb.b_interlaced],
|
|
DCT_LUMA_8x8, 16+i_qbits, i_lambda2, 0, 64 );
|
|
}
|
|
|