/* * H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at> * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * Context Adaptive Binary Arithmetic Coder inline functions */ #ifndef AVCODEC_CABAC_FUNCTIONS_H #define AVCODEC_CABAC_FUNCTIONS_H #include <stdint.h> #include "cabac.h" #include "config.h" #ifndef UNCHECKED_BITSTREAM_READER #define UNCHECKED_BITSTREAM_READER !CONFIG_SAFE_BITSTREAM_READER #endif #if ARCH_AARCH64 # include "aarch64/cabac.h" #endif #if ARCH_ARM # include "arm/cabac.h" #endif #if ARCH_X86 # include "x86/cabac.h" #endif static const uint8_t * const ff_h264_norm_shift = ff_h264_cabac_tables + H264_NORM_SHIFT_OFFSET; static const uint8_t * const ff_h264_lps_range = ff_h264_cabac_tables + H264_LPS_RANGE_OFFSET; static const uint8_t * const ff_h264_mlps_state = ff_h264_cabac_tables + H264_MLPS_STATE_OFFSET; static const uint8_t * const ff_h264_last_coeff_flag_offset_8x8 = ff_h264_cabac_tables + H264_LAST_COEFF_FLAG_OFFSET_8x8_OFFSET; #if !defined(get_cabac_bypass) || !defined(get_cabac_terminate) static void refill(CABACContext *c){ #if CABAC_BITS == 16 c->low+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1); #else c->low+= c->bytestream[0]<<1; #endif c->low -= CABAC_MASK; #if !UNCHECKED_BITSTREAM_READER if (c->bytestream < c->bytestream_end) #endif c->bytestream += CABAC_BITS / 8; } #endif #ifndef get_cabac_terminate static inline void renorm_cabac_decoder_once(CABACContext *c){ int shift= (uint32_t)(c->range - 0x100)>>31; c->range<<= shift; c->low <<= shift; if(!(c->low & CABAC_MASK)) refill(c); } #endif #ifndef get_cabac_inline static void refill2(CABACContext *c){ int i; unsigned x; #if !HAVE_FAST_CLZ x= c->low ^ (c->low-1); i= 7 - ff_h264_norm_shift[x>>(CABAC_BITS-1)]; #else i = ff_ctz(c->low) - CABAC_BITS; #endif x= -CABAC_MASK; #if CABAC_BITS == 16 x+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1); #else x+= c->bytestream[0]<<1; #endif c->low += x<<i; #if !UNCHECKED_BITSTREAM_READER if (c->bytestream < c->bytestream_end) #endif c->bytestream += CABAC_BITS/8; } #endif #ifndef get_cabac_inline static av_always_inline int get_cabac_inline(CABACContext *c, uint8_t * const state){ int s = *state; int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + s]; int bit, lps_mask; c->range -= RangeLPS; lps_mask= ((c->range<<(CABAC_BITS+1)) - c->low)>>31; c->low -= (c->range<<(CABAC_BITS+1)) & lps_mask; c->range += (RangeLPS - c->range) & lps_mask; s^=lps_mask; *state= (ff_h264_mlps_state+128)[s]; bit= s&1; lps_mask= ff_h264_norm_shift[c->range]; c->range<<= lps_mask; c->low <<= lps_mask; if(!(c->low & CABAC_MASK)) refill2(c); return bit; } #endif static int av_noinline av_unused get_cabac_noinline(CABACContext *c, uint8_t * const state){ return get_cabac_inline(c,state); } static int av_unused get_cabac(CABACContext *c, uint8_t * const state){ return get_cabac_inline(c,state); } #ifndef get_cabac_bypass static int av_unused get_cabac_bypass(CABACContext *c){ int range; c->low += c->low; if(!(c->low & CABAC_MASK)) refill(c); range= c->range<<(CABAC_BITS+1); if(c->low < range){ return 0; }else{ c->low -= range; return 1; } } #endif #ifndef get_cabac_bypass_sign static av_always_inline int get_cabac_bypass_sign(CABACContext *c, int val){ int range, mask; c->low += c->low; if(!(c->low & CABAC_MASK)) refill(c); range= c->range<<(CABAC_BITS+1); c->low -= range; mask= c->low >> 31; range &= mask; c->low += range; return (val^mask)-mask; } #endif /** * @return the number of bytes read or 0 if no end */ #ifndef get_cabac_terminate static int av_unused get_cabac_terminate(CABACContext *c){ c->range -= 2; if(c->low < c->range<<(CABAC_BITS+1)){ renorm_cabac_decoder_once(c); return 0; }else{ return c->bytestream - c->bytestream_start; } } #endif /** * Skip @p n bytes and reset the decoder. * @return the address of the first skipped byte or NULL if there's less than @p n bytes left */ #ifndef skip_bytes static av_unused const uint8_t* skip_bytes(CABACContext *c, int n) { const uint8_t *ptr = c->bytestream; if (c->low & 0x1) ptr--; #if CABAC_BITS == 16 if (c->low & 0x1FF) ptr--; #endif if ((int) (c->bytestream_end - ptr) < n) return NULL; if (ff_init_cabac_decoder(c, ptr + n, c->bytestream_end - ptr - n) < 0) return NULL; return ptr; } #endif #endif /* AVCODEC_CABAC_FUNCTIONS_H */