/* * 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 libavcodec/cabac.h * Context Adaptive Binary Arithmetic Coder. */ #ifndef AVCODEC_CABAC_H #define AVCODEC_CABAC_H #include "bitstream.h" //#undef NDEBUG #include <assert.h> #include "libavutil/x86_cpu.h" #define CABAC_BITS 16 #define CABAC_MASK ((1<<CABAC_BITS)-1) #define BRANCHLESS_CABAC_DECODER 1 //#define ARCH_X86_DISABLED 1 typedef struct CABACContext{ int low; int range; int outstanding_count; #ifdef STRICT_LIMITS int symCount; #endif const uint8_t *bytestream_start; const uint8_t *bytestream; const uint8_t *bytestream_end; PutBitContext pb; }CABACContext; extern uint8_t ff_h264_mlps_state[4*64]; extern uint8_t ff_h264_lps_range[4*2*64]; ///< rangeTabLPS extern uint8_t ff_h264_mps_state[2*64]; ///< transIdxMPS extern uint8_t ff_h264_lps_state[2*64]; ///< transIdxLPS extern const uint8_t ff_h264_norm_shift[512]; void ff_init_cabac_encoder(CABACContext *c, uint8_t *buf, int buf_size); void ff_init_cabac_decoder(CABACContext *c, const uint8_t *buf, int buf_size); void ff_init_cabac_states(CABACContext *c); static inline void put_cabac_bit(CABACContext *c, int b){ put_bits(&c->pb, 1, b); for(;c->outstanding_count; c->outstanding_count--){ put_bits(&c->pb, 1, 1-b); } } static inline void renorm_cabac_encoder(CABACContext *c){ while(c->range < 0x100){ //FIXME optimize if(c->low<0x100){ put_cabac_bit(c, 0); }else if(c->low<0x200){ c->outstanding_count++; c->low -= 0x100; }else{ put_cabac_bit(c, 1); c->low -= 0x200; } c->range+= c->range; c->low += c->low; } } #ifdef TEST static void put_cabac(CABACContext *c, uint8_t * const state, int bit){ int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + *state]; if(bit == ((*state)&1)){ c->range -= RangeLPS; *state= ff_h264_mps_state[*state]; }else{ c->low += c->range - RangeLPS; c->range = RangeLPS; *state= ff_h264_lps_state[*state]; } renorm_cabac_encoder(c); #ifdef STRICT_LIMITS c->symCount++; #endif } static void put_cabac_static(CABACContext *c, int RangeLPS, int bit){ assert(c->range > RangeLPS); if(!bit){ c->range -= RangeLPS; }else{ c->low += c->range - RangeLPS; c->range = RangeLPS; } renorm_cabac_encoder(c); #ifdef STRICT_LIMITS c->symCount++; #endif } /** * @param bit 0 -> write zero bit, !=0 write one bit */ static void put_cabac_bypass(CABACContext *c, int bit){ c->low += c->low; if(bit){ c->low += c->range; } //FIXME optimize if(c->low<0x200){ put_cabac_bit(c, 0); }else if(c->low<0x400){ c->outstanding_count++; c->low -= 0x200; }else{ put_cabac_bit(c, 1); c->low -= 0x400; } #ifdef STRICT_LIMITS c->symCount++; #endif } /** * * @return the number of bytes written */ static int put_cabac_terminate(CABACContext *c, int bit){ c->range -= 2; if(!bit){ renorm_cabac_encoder(c); }else{ c->low += c->range; c->range= 2; renorm_cabac_encoder(c); assert(c->low <= 0x1FF); put_cabac_bit(c, c->low>>9); put_bits(&c->pb, 2, ((c->low>>7)&3)|1); flush_put_bits(&c->pb); //FIXME FIXME FIXME XXX wrong } #ifdef STRICT_LIMITS c->symCount++; #endif return (put_bits_count(&c->pb)+7)>>3; } /** * put (truncated) unary binarization. */ static void put_cabac_u(CABACContext *c, uint8_t * state, int v, int max, int max_index, int truncated){ int i; assert(v <= max); #if 1 for(i=0; i<v; i++){ put_cabac(c, state, 1); if(i < max_index) state++; } if(truncated==0 || v<max) put_cabac(c, state, 0); #else if(v <= max_index){ for(i=0; i<v; i++){ put_cabac(c, state+i, 1); } if(truncated==0 || v<max) put_cabac(c, state+i, 0); }else{ for(i=0; i<=max_index; i++){ put_cabac(c, state+i, 1); } for(; i<v; i++){ put_cabac(c, state+max_index, 1); } if(truncated==0 || v<max) put_cabac(c, state+max_index, 0); } #endif } /** * put unary exp golomb k-th order binarization. */ static void put_cabac_ueg(CABACContext *c, uint8_t * state, int v, int max, int is_signed, int k, int max_index){ int i; if(v==0) put_cabac(c, state, 0); else{ const int sign= v < 0; if(is_signed) v= FFABS(v); if(v<max){ for(i=0; i<v; i++){ put_cabac(c, state, 1); if(i < max_index) state++; } put_cabac(c, state, 0); }else{ int m= 1<<k; for(i=0; i<max; i++){ put_cabac(c, state, 1); if(i < max_index) state++; } v -= max; while(v >= m){ //FIXME optimize put_cabac_bypass(c, 1); v-= m; m+= m; } put_cabac_bypass(c, 0); while(m>>=1){ put_cabac_bypass(c, v&m); } } if(is_signed) put_cabac_bypass(c, sign); } } #endif /* TEST */ 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; c->bytestream+= CABAC_BITS/8; } #if ! ( ARCH_X86 && HAVE_7REGS && HAVE_EBX_AVAILABLE && !defined(BROKEN_RELOCATIONS) ) static void refill2(CABACContext *c){ int i, x; x= c->low ^ (c->low-1); i= 7 - ff_h264_norm_shift[x>>(CABAC_BITS-1)]; 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; c->bytestream+= CABAC_BITS/8; } #endif static inline void renorm_cabac_decoder(CABACContext *c){ while(c->range < 0x100){ c->range+= c->range; c->low+= c->low; if(!(c->low & CABAC_MASK)) refill(c); } } static inline void renorm_cabac_decoder_once(CABACContext *c){ #ifdef ARCH_X86_DISABLED int temp; #if 0 //P3:683 athlon:475 __asm__( "lea -0x100(%0), %2 \n\t" "shr $31, %2 \n\t" //FIXME 31->63 for x86-64 "shl %%cl, %0 \n\t" "shl %%cl, %1 \n\t" : "+r"(c->range), "+r"(c->low), "+c"(temp) ); #elif 0 //P3:680 athlon:474 __asm__( "cmp $0x100, %0 \n\t" "setb %%cl \n\t" //FIXME 31->63 for x86-64 "shl %%cl, %0 \n\t" "shl %%cl, %1 \n\t" : "+r"(c->range), "+r"(c->low), "+c"(temp) ); #elif 1 int temp2; //P3:665 athlon:517 __asm__( "lea -0x100(%0), %%eax \n\t" "cltd \n\t" "mov %0, %%eax \n\t" "and %%edx, %0 \n\t" "and %1, %%edx \n\t" "add %%eax, %0 \n\t" "add %%edx, %1 \n\t" : "+r"(c->range), "+r"(c->low), "+a"(temp), "+d"(temp2) ); #elif 0 int temp2; //P3:673 athlon:509 __asm__( "cmp $0x100, %0 \n\t" "sbb %%edx, %%edx \n\t" "mov %0, %%eax \n\t" "and %%edx, %0 \n\t" "and %1, %%edx \n\t" "add %%eax, %0 \n\t" "add %%edx, %1 \n\t" : "+r"(c->range), "+r"(c->low), "+a"(temp), "+d"(temp2) ); #else int temp2; //P3:677 athlon:511 __asm__( "cmp $0x100, %0 \n\t" "lea (%0, %0), %%eax \n\t" "lea (%1, %1), %%edx \n\t" "cmovb %%eax, %0 \n\t" "cmovb %%edx, %1 \n\t" : "+r"(c->range), "+r"(c->low), "+a"(temp), "+d"(temp2) ); #endif #else //P3:675 athlon:476 int shift= (uint32_t)(c->range - 0x100)>>31; c->range<<= shift; c->low <<= shift; #endif if(!(c->low & CABAC_MASK)) refill(c); } static av_always_inline int get_cabac_inline(CABACContext *c, uint8_t * const state){ //FIXME gcc generates duplicate load/stores for c->low and c->range #define LOW "0" #define RANGE "4" #if ARCH_X86_64 #define BYTESTART "16" #define BYTE "24" #define BYTEEND "32" #else #define BYTESTART "12" #define BYTE "16" #define BYTEEND "20" #endif #if ARCH_X86 && HAVE_7REGS && HAVE_EBX_AVAILABLE && !defined(BROKEN_RELOCATIONS) int bit; #ifndef BRANCHLESS_CABAC_DECODER __asm__ volatile( "movzbl (%1), %0 \n\t" "movl "RANGE "(%2), %%ebx \n\t" "movl "RANGE "(%2), %%edx \n\t" "andl $0xC0, %%ebx \n\t" "movzbl "MANGLE(ff_h264_lps_range)"(%0, %%ebx, 2), %%esi\n\t" "movl "LOW "(%2), %%ebx \n\t" //eax:state ebx:low, edx:range, esi:RangeLPS "subl %%esi, %%edx \n\t" "movl %%edx, %%ecx \n\t" "shll $17, %%ecx \n\t" "cmpl %%ecx, %%ebx \n\t" " ja 1f \n\t" #if 1 //athlon:4067 P3:4110 "lea -0x100(%%edx), %%ecx \n\t" "shr $31, %%ecx \n\t" "shl %%cl, %%edx \n\t" "shl %%cl, %%ebx \n\t" #else //athlon:4057 P3:4130 "cmp $0x100, %%edx \n\t" //FIXME avoidable "setb %%cl \n\t" "shl %%cl, %%edx \n\t" "shl %%cl, %%ebx \n\t" #endif "movzbl "MANGLE(ff_h264_mps_state)"(%0), %%ecx \n\t" "movb %%cl, (%1) \n\t" //eax:state ebx:low, edx:range, esi:RangeLPS "test %%bx, %%bx \n\t" " jnz 2f \n\t" "mov "BYTE "(%2), %%"REG_S" \n\t" "subl $0xFFFF, %%ebx \n\t" "movzwl (%%"REG_S"), %%ecx \n\t" "bswap %%ecx \n\t" "shrl $15, %%ecx \n\t" "add $2, %%"REG_S" \n\t" "addl %%ecx, %%ebx \n\t" "mov %%"REG_S", "BYTE "(%2) \n\t" "jmp 2f \n\t" "1: \n\t" //eax:state ebx:low, edx:range, esi:RangeLPS "subl %%ecx, %%ebx \n\t" "movl %%esi, %%edx \n\t" "movzbl " MANGLE(ff_h264_norm_shift) "(%%esi), %%ecx \n\t" "shll %%cl, %%ebx \n\t" "shll %%cl, %%edx \n\t" "movzbl "MANGLE(ff_h264_lps_state)"(%0), %%ecx \n\t" "movb %%cl, (%1) \n\t" "add $1, %0 \n\t" "test %%bx, %%bx \n\t" " jnz 2f \n\t" "mov "BYTE "(%2), %%"REG_c" \n\t" "movzwl (%%"REG_c"), %%esi \n\t" "bswap %%esi \n\t" "shrl $15, %%esi \n\t" "subl $0xFFFF, %%esi \n\t" "add $2, %%"REG_c" \n\t" "mov %%"REG_c", "BYTE "(%2) \n\t" "leal -1(%%ebx), %%ecx \n\t" "xorl %%ebx, %%ecx \n\t" "shrl $15, %%ecx \n\t" "movzbl " MANGLE(ff_h264_norm_shift) "(%%ecx), %%ecx \n\t" "neg %%ecx \n\t" "add $7, %%ecx \n\t" "shll %%cl , %%esi \n\t" "addl %%esi, %%ebx \n\t" "2: \n\t" "movl %%edx, "RANGE "(%2) \n\t" "movl %%ebx, "LOW "(%2) \n\t" :"=&a"(bit) //FIXME this is fragile gcc either runs out of registers or miscompiles it (for example if "+a"(bit) or "+m"(*state) is used :"r"(state), "r"(c) : "%"REG_c, "%ebx", "%edx", "%"REG_S, "memory" ); bit&=1; #else /* BRANCHLESS_CABAC_DECODER */ #if HAVE_FAST_CMOV #define BRANCHLESS_GET_CABAC_UPDATE(ret, cabac, statep, low, lowword, range, tmp, tmpbyte)\ "mov "tmp" , %%ecx \n\t"\ "shl $17 , "tmp" \n\t"\ "cmp "low" , "tmp" \n\t"\ "cmova %%ecx , "range" \n\t"\ "sbb %%ecx , %%ecx \n\t"\ "and %%ecx , "tmp" \n\t"\ "sub "tmp" , "low" \n\t"\ "xor %%ecx , "ret" \n\t" #else /* HAVE_FAST_CMOV */ #define BRANCHLESS_GET_CABAC_UPDATE(ret, cabac, statep, low, lowword, range, tmp, tmpbyte)\ "mov "tmp" , %%ecx \n\t"\ "shl $17 , "tmp" \n\t"\ "sub "low" , "tmp" \n\t"\ "sar $31 , "tmp" \n\t" /*lps_mask*/\ "sub %%ecx , "range" \n\t" /*RangeLPS - range*/\ "and "tmp" , "range" \n\t" /*(RangeLPS - range)&lps_mask*/\ "add %%ecx , "range" \n\t" /*new range*/\ "shl $17 , %%ecx \n\t"\ "and "tmp" , %%ecx \n\t"\ "sub %%ecx , "low" \n\t"\ "xor "tmp" , "ret" \n\t" #endif /* HAVE_FAST_CMOV */ #define BRANCHLESS_GET_CABAC(ret, cabac, statep, low, lowword, range, tmp, tmpbyte)\ "movzbl "statep" , "ret" \n\t"\ "mov "range" , "tmp" \n\t"\ "and $0xC0 , "range" \n\t"\ "movzbl "MANGLE(ff_h264_lps_range)"("ret", "range", 2), "range" \n\t"\ "sub "range" , "tmp" \n\t"\ BRANCHLESS_GET_CABAC_UPDATE(ret, cabac, statep, low, lowword, range, tmp, tmpbyte)\ "movzbl " MANGLE(ff_h264_norm_shift) "("range"), %%ecx \n\t"\ "shl %%cl , "range" \n\t"\ "movzbl "MANGLE(ff_h264_mlps_state)"+128("ret"), "tmp" \n\t"\ "mov "tmpbyte" , "statep" \n\t"\ "shl %%cl , "low" \n\t"\ "test "lowword" , "lowword" \n\t"\ " jnz 1f \n\t"\ "mov "BYTE"("cabac"), %%"REG_c" \n\t"\ "movzwl (%%"REG_c") , "tmp" \n\t"\ "bswap "tmp" \n\t"\ "shr $15 , "tmp" \n\t"\ "sub $0xFFFF , "tmp" \n\t"\ "add $2 , %%"REG_c" \n\t"\ "mov %%"REG_c" , "BYTE "("cabac") \n\t"\ "lea -1("low") , %%ecx \n\t"\ "xor "low" , %%ecx \n\t"\ "shr $15 , %%ecx \n\t"\ "movzbl " MANGLE(ff_h264_norm_shift) "(%%ecx), %%ecx \n\t"\ "neg %%ecx \n\t"\ "add $7 , %%ecx \n\t"\ "shl %%cl , "tmp" \n\t"\ "add "tmp" , "low" \n\t"\ "1: \n\t" __asm__ volatile( "movl "RANGE "(%2), %%esi \n\t" "movl "LOW "(%2), %%ebx \n\t" BRANCHLESS_GET_CABAC("%0", "%2", "(%1)", "%%ebx", "%%bx", "%%esi", "%%edx", "%%dl") "movl %%esi, "RANGE "(%2) \n\t" "movl %%ebx, "LOW "(%2) \n\t" :"=&a"(bit) :"r"(state), "r"(c) : "%"REG_c, "%ebx", "%edx", "%esi", "memory" ); bit&=1; #endif /* BRANCHLESS_CABAC_DECODER */ #else /* ARCH_X86 && HAVE_7REGS && HAVE_EBX_AVAILABLE && !defined(BROKEN_RELOCATIONS) */ int s = *state; int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + s]; int bit, lps_mask av_unused; c->range -= RangeLPS; #ifndef BRANCHLESS_CABAC_DECODER if(c->low < (c->range<<(CABAC_BITS+1))){ bit= s&1; *state= ff_h264_mps_state[s]; renorm_cabac_decoder_once(c); }else{ bit= ff_h264_norm_shift[RangeLPS]; c->low -= (c->range<<(CABAC_BITS+1)); *state= ff_h264_lps_state[s]; c->range = RangeLPS<<bit; c->low <<= bit; bit= (s&1)^1; if(!(c->low & CABAC_MASK)){ refill2(c); } } #else /* BRANCHLESS_CABAC_DECODER */ 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); #endif /* BRANCHLESS_CABAC_DECODER */ #endif /* ARCH_X86 && HAVE_7REGS && HAVE_EBX_AVAILABLE && !defined(BROKEN_RELOCATIONS) */ return bit; } 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); } static int av_unused get_cabac_bypass(CABACContext *c){ #if 0 //not faster int bit; __asm__ volatile( "movl "RANGE "(%1), %%ebx \n\t" "movl "LOW "(%1), %%eax \n\t" "shl $17, %%ebx \n\t" "add %%eax, %%eax \n\t" "sub %%ebx, %%eax \n\t" "cltd \n\t" "and %%edx, %%ebx \n\t" "add %%ebx, %%eax \n\t" "test %%ax, %%ax \n\t" " jnz 1f \n\t" "movl "BYTE "(%1), %%"REG_b" \n\t" "subl $0xFFFF, %%eax \n\t" "movzwl (%%"REG_b"), %%ecx \n\t" "bswap %%ecx \n\t" "shrl $15, %%ecx \n\t" "addl $2, %%"REG_b" \n\t" "addl %%ecx, %%eax \n\t" "movl %%"REG_b", "BYTE "(%1) \n\t" "1: \n\t" "movl %%eax, "LOW "(%1) \n\t" :"=&d"(bit) :"r"(c) : "%eax", "%"REG_b, "%ecx", "memory" ); return bit+1; #else 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 } static av_always_inline int get_cabac_bypass_sign(CABACContext *c, int val){ #if ARCH_X86 && !(defined(PIC) && defined(__GNUC__)) __asm__ volatile( "movl "RANGE "(%1), %%ebx \n\t" "movl "LOW "(%1), %%eax \n\t" "shl $17, %%ebx \n\t" "add %%eax, %%eax \n\t" "sub %%ebx, %%eax \n\t" "cltd \n\t" "and %%edx, %%ebx \n\t" "add %%ebx, %%eax \n\t" "xor %%edx, %%ecx \n\t" "sub %%edx, %%ecx \n\t" "test %%ax, %%ax \n\t" " jnz 1f \n\t" "mov "BYTE "(%1), %%"REG_b" \n\t" "subl $0xFFFF, %%eax \n\t" "movzwl (%%"REG_b"), %%edx \n\t" "bswap %%edx \n\t" "shrl $15, %%edx \n\t" "add $2, %%"REG_b" \n\t" "addl %%edx, %%eax \n\t" "mov %%"REG_b", "BYTE "(%1) \n\t" "1: \n\t" "movl %%eax, "LOW "(%1) \n\t" :"+c"(val) :"r"(c) : "%eax", "%"REG_b, "%edx", "memory" ); return val; #else 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 */ 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; } } #if 0 /** * Get (truncated) unary binarization. */ static int get_cabac_u(CABACContext *c, uint8_t * state, int max, int max_index, int truncated){ int i; for(i=0; i<max; i++){ if(get_cabac(c, state)==0) return i; if(i< max_index) state++; } return truncated ? max : -1; } /** * get unary exp golomb k-th order binarization. */ static int get_cabac_ueg(CABACContext *c, uint8_t * state, int max, int is_signed, int k, int max_index){ int i, v; int m= 1<<k; if(get_cabac(c, state)==0) return 0; if(0 < max_index) state++; for(i=1; i<max; i++){ if(get_cabac(c, state)==0){ if(is_signed && get_cabac_bypass(c)){ return -i; }else return i; } if(i < max_index) state++; } while(get_cabac_bypass(c)){ i+= m; m+= m; } v=0; while(m>>=1){ v+= v + get_cabac_bypass(c); } i += v; if(is_signed && get_cabac_bypass(c)){ return -i; }else return i; } #endif /* 0 */ #endif /* AVCODEC_CABAC_H */