nengel@2: /*
nengel@2:  * H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
nengel@2:  * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
nengel@2:  *
nengel@2:  * This file is part of FFmpeg.
nengel@2:  *
nengel@2:  * FFmpeg is free software; you can redistribute it and/or
nengel@2:  * modify it under the terms of the GNU Lesser General Public
nengel@2:  * License as published by the Free Software Foundation; either
nengel@2:  * version 2.1 of the License, or (at your option) any later version.
nengel@2:  *
nengel@2:  * FFmpeg is distributed in the hope that it will be useful,
nengel@2:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
nengel@2:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
nengel@2:  * Lesser General Public License for more details.
nengel@2:  *
nengel@2:  * You should have received a copy of the GNU Lesser General Public
nengel@2:  * License along with FFmpeg; if not, write to the Free Software
nengel@2:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
nengel@2:  */
nengel@2: 
nengel@2: /**
nengel@2:  * @file
nengel@2:  * Context Adaptive Binary Arithmetic Coder.
nengel@2:  */
nengel@2: 
nengel@2: #ifndef AVCODEC_CABAC_H
nengel@2: #define AVCODEC_CABAC_H
nengel@2: 
nengel@2: //#undef NDEBUG
nengel@2: #include <assert.h>
nengel@2: #include "h264_dma.h"
nengel@2: #include "libavutil/x86_cpu.h"
nengel@2: #include "libavutil/attributes.h"
nengel@2: 
nengel@2: #define CABAC_BITS 16
nengel@2: #define CABAC_MASK ((1<<CABAC_BITS)-1)
nengel@2: #define BRANCHLESS_CABAC_DECODER 1
nengel@2: 
nengel@2: typedef struct CABACContext{
nengel@2:     int low;
nengel@2:     int range;
nengel@2:     int outstanding_count;
nengel@2: #ifdef STRICT_LIMITS
nengel@2:     int symCount;
nengel@2: #endif
nengel@2: 	const uint8_t *bytestream_ea_start;
nengel@2:     const uint8_t *bytestream_ea;
nengel@2: 	const uint8_t *bytestream_ea_end;
nengel@2: 	int slot;
nengel@2: 	int bufsize;
nengel@2: 
nengel@2: 	uint8_t *bytestream_start;
nengel@2:     uint8_t *bytestream;
nengel@2:     uint8_t *bytestream_end;
nengel@2:     uint8_t  cabac_state[460];
nengel@2: }CABACContext;
nengel@2: 
nengel@2: extern uint8_t ff_h264_mlps_state[4*64];
nengel@2: extern uint8_t ff_h264_lps_range[4*2*64];  ///< rangeTabLPS
nengel@2: extern uint8_t ff_h264_mps_state[2*64];     ///< transIdxMPS
nengel@2: extern uint8_t ff_h264_lps_state[2*64];     ///< transIdxLPS
nengel@2: extern const uint8_t ff_h264_norm_shift[512];
nengel@2: 
nengel@2: void ff_init_cabac_states(void);
nengel@2: 
nengel@2: extern DECLARE_ALIGNED(128,uint8_t, bytestream_ls[4096]);
nengel@2: extern int bytecount;
nengel@2: static inline void dma_cabac(CABACContext *c){
nengel@2: 	bytecount++;
nengel@2: 	if (c->bytestream == c->bytestream_end){
nengel@2: 		if (c->bufsize>0){
nengel@2: 			int size = (c->bufsize > sizeof(bytestream_ls)) ?  sizeof(bytestream_ls) : c->bufsize;
nengel@2: 			int align = size &0xF;
nengel@2: 			int dma_size = size + (align? 16-align : 0);
nengel@2: 
nengel@2: 			spu_dma_get(bytestream_ls, (unsigned) c->bytestream_ea, dma_size, ED_raw);
nengel@2: 			wait_dma_id(ED_raw);
nengel@2: 			c->bytestream = bytestream_ls;
nengel@2: 			c->bytestream_end = &bytestream_ls[size];
nengel@2: 			c->bytestream_ea += dma_size;
nengel@2: 			c->bufsize -= size;
nengel@2: 		} 
nengel@2: 		bytecount =0;
nengel@2: 	}else if((unsigned)c->bytestream > (unsigned)c->bytestream_end +2){		
nengel@2: 		//fprintf(stderr, "Read beyond end of frame %d\n", c->bufsize);
nengel@2: 		bytecount =0;
nengel@2: 	}
nengel@2: }
nengel@2: 
nengel@2: static void refill(CABACContext *c){
nengel@2: 	dma_cabac(c); 
nengel@2: 
nengel@2: 	c->low+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);
nengel@2: 
nengel@2:     c->low -= CABAC_MASK;
nengel@2:     c->bytestream+= CABAC_BITS/8;
nengel@2: }
nengel@2: 
nengel@2: static void refill2(CABACContext *c){
nengel@2:     int i, x;
nengel@2: 
nengel@2: 	dma_cabac(c);
nengel@2: 
nengel@2:     x= c->low ^ (c->low-1);
nengel@2:     i= 7 - ff_h264_norm_shift[x>>(CABAC_BITS-1)];
nengel@2: 
nengel@2:     x= -CABAC_MASK;
nengel@2: 
nengel@2: 	x+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);
nengel@2: 
nengel@2:     c->low += x<<i;
nengel@2:     c->bytestream+= CABAC_BITS/8;
nengel@2: }
nengel@2: 
nengel@2: static inline void renorm_cabac_decoder(CABACContext *c){
nengel@2:     while(c->range < 0x100){
nengel@2:         c->range+= c->range;
nengel@2:         c->low+= c->low;
nengel@2:         if(!(c->low & CABAC_MASK))
nengel@2:             refill(c);
nengel@2:     }
nengel@2: }
nengel@2: 
nengel@2: static inline void renorm_cabac_decoder_once(CABACContext *c){
nengel@2: 
nengel@2:     int shift= (uint32_t)(c->range - 0x100)>>31;
nengel@2:     c->range<<= shift;
nengel@2:     c->low  <<= shift;
nengel@2: 
nengel@2:     if(!(c->low & CABAC_MASK))
nengel@2:         refill(c);
nengel@2: }
nengel@2: 
nengel@2: static av_always_inline int get_cabac_inline(CABACContext *c, uint8_t * const state){
nengel@2: 
nengel@2:     int s = *state;
nengel@2:     int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + s];
nengel@2:     int bit, lps_mask av_unused;
nengel@2: 
nengel@2:     c->range -= RangeLPS;
nengel@2: #ifndef BRANCHLESS_CABAC_DECODER
nengel@2:     if(c->low < (c->range<<(CABAC_BITS+1))){
nengel@2:         bit= s&1;
nengel@2:         *state= ff_h264_mps_state[s];
nengel@2:         renorm_cabac_decoder_once(c);
nengel@2:     }else{
nengel@2:         bit= ff_h264_norm_shift[RangeLPS];
nengel@2:         c->low -= (c->range<<(CABAC_BITS+1));
nengel@2:         *state= ff_h264_lps_state[s];
nengel@2:         c->range = RangeLPS<<bit;
nengel@2:         c->low <<= bit;
nengel@2:         bit= (s&1)^1;
nengel@2: 
nengel@2:         if(!(c->low & CABAC_MASK)){
nengel@2:             refill2(c);
nengel@2:         }
nengel@2:     }
nengel@2: #else /* BRANCHLESS_CABAC_DECODER */
nengel@2:     lps_mask= ((c->range<<(CABAC_BITS+1)) - c->low)>>31;
nengel@2: 
nengel@2:     c->low -= (c->range<<(CABAC_BITS+1)) & lps_mask;
nengel@2:     c->range += (RangeLPS - c->range) & lps_mask;
nengel@2: 
nengel@2:     s^=lps_mask;
nengel@2:     *state= (ff_h264_mlps_state+128)[s];
nengel@2:     bit= s&1;
nengel@2: 
nengel@2:     lps_mask= ff_h264_norm_shift[c->range];
nengel@2:     c->range<<= lps_mask;
nengel@2:     c->low  <<= lps_mask;
nengel@2:     if(!(c->low & CABAC_MASK))
nengel@2:         refill2(c);
nengel@2: #endif /* BRANCHLESS_CABAC_DECODER */
nengel@2: 
nengel@2:     return bit;
nengel@2: }
nengel@2: 
nengel@2: static int av_noinline av_unused get_cabac_noinline(CABACContext *c, uint8_t * const state){
nengel@2:     return get_cabac_inline(c, state);
nengel@2: }
nengel@2: 
nengel@2: static int av_unused get_cabac(CABACContext *c, uint8_t * const state){
nengel@2:     return get_cabac_inline(c, state);
nengel@2: }
nengel@2: 
nengel@2: static int av_unused get_cabac_bypass(CABACContext *c){
nengel@2: 
nengel@2:     int range;
nengel@2:     c->low += c->low;
nengel@2: 
nengel@2:     if(!(c->low & CABAC_MASK))
nengel@2:         refill(c);
nengel@2: 
nengel@2:     range= c->range<<(CABAC_BITS+1);
nengel@2:     if(c->low < range){
nengel@2:         return 0;
nengel@2:     }else{
nengel@2:         c->low -= range;
nengel@2:         return 1;
nengel@2:     }
nengel@2: }
nengel@2: 
nengel@2: static av_always_inline int get_cabac_bypass_sign(CABACContext *c, int val){
nengel@2:     int range, mask;
nengel@2:     c->low += c->low;
nengel@2: 
nengel@2:     if(!(c->low & CABAC_MASK))
nengel@2:         refill(c);
nengel@2: 
nengel@2:     range= c->range<<(CABAC_BITS+1);
nengel@2:     c->low -= range;
nengel@2:     mask= c->low >> 31;
nengel@2:     range &= mask;
nengel@2:     c->low += range;
nengel@2:     return (val^mask)-mask;
nengel@2: }
nengel@2: 
nengel@2: /**
nengel@2:  *
nengel@2:  * @return the number of bytes read or 0 if no end
nengel@2:  */
nengel@2: static int av_unused get_cabac_terminate(CABACContext *c){
nengel@2:     c->range -= 2;
nengel@2:     if(c->low < c->range<<(CABAC_BITS+1)){
nengel@2:         renorm_cabac_decoder_once(c);
nengel@2:         return 0;
nengel@2:     }else{
nengel@2:         return c->bytestream - c->bytestream_start;
nengel@2:     }
nengel@2: }
nengel@2: 
nengel@2: #endif /* AVCODEC_CABAC_H */