| /* |
| * 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 |
| #if ARCH_MIPS |
| # include "mips/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 */ |