101 lines
3.8 KiB
C
101 lines
3.8 KiB
C
/*****************************************************************************
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* vlc.c : vlc tables
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*****************************************************************************
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* Copyright (C) 2003-2025 x264 project
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*
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* Authors: Laurent Aimar <fenrir@via.ecp.fr>
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* Fiona Glaser <fiona@x264.com>
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* Henrik Gramner <henrik@gramner.com>
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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., 51 Franklin Street, Fifth Floor, Boston, MA 02111, USA.
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*
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* This program is also available under a commercial proprietary license.
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* For more information, contact us at licensing@x264.com.
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*****************************************************************************/
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#include "common.h"
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vlc_large_t x264_level_token[7][LEVEL_TABLE_SIZE];
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uint32_t x264_run_before[1<<16];
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void x264_cavlc_init( x264_t *h )
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{
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for( int i_suffix = 0; i_suffix < 7; i_suffix++ )
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for( int16_t level = -LEVEL_TABLE_SIZE/2; level < LEVEL_TABLE_SIZE/2; level++ )
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{
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int mask = level >> 15;
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int abs_level = (level^mask)-mask;
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int i_level_code = abs_level ? abs_level*2-mask-2 : 0;
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int i_next = i_suffix;
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vlc_large_t *vlc = &x264_level_token[i_suffix][level+LEVEL_TABLE_SIZE/2];
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if( ( i_level_code >> i_suffix ) < 14 )
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{
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vlc->i_size = (i_level_code >> i_suffix) + 1 + i_suffix;
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vlc->i_bits = (1<<i_suffix) + (i_level_code & ((1<<i_suffix)-1));
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}
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else if( i_suffix == 0 && i_level_code < 30 )
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{
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vlc->i_size = 19;
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vlc->i_bits = (1<<4) + (i_level_code - 14);
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}
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else if( i_suffix > 0 && ( i_level_code >> i_suffix ) == 14 )
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{
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vlc->i_size = 15 + i_suffix;
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vlc->i_bits = (1<<i_suffix) + (i_level_code & ((1<<i_suffix)-1));
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}
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else
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{
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i_level_code -= 15 << i_suffix;
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if( i_suffix == 0 )
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i_level_code -= 15;
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vlc->i_size = 28;
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vlc->i_bits = (1<<12) + i_level_code;
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}
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if( i_next == 0 )
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i_next++;
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if( abs_level > (3 << (i_next-1)) && i_next < 6 )
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i_next++;
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vlc->i_next = i_next;
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}
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x264_run_before[0] = 0;
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x264_run_before[1] = 0;
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for( uint32_t i = 2; i < (1<<16); i++ )
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{
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x264_run_level_t runlevel;
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ALIGNED_ARRAY_16( dctcoef, dct, [16] );
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int size = 0;
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int bits = 0;
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for( int j = 0; j < 16; j++ )
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dct[j] = i&(1<<j);
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int total = h->quantf.coeff_level_run[DCT_LUMA_4x4]( dct, &runlevel );
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int zeros = runlevel.last + 1 - total;
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uint32_t mask = i << (x264_clz( i ) + 1);
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for( int j = 0; j < total-1 && zeros > 0; j++ )
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{
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int idx = X264_MIN(zeros, 7) - 1;
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int run = x264_clz( mask );
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int len = x264_run_before_init[idx][run].i_size;
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size += len;
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bits <<= len;
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bits |= x264_run_before_init[idx][run].i_bits;
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zeros -= run;
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mask <<= run + 1;
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}
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x264_run_before[i] = (bits << 5) + size;
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}
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}
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