X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavcodec%2Fcabac.c;h=65579d8d3ba4834b9531c1c2ee07add56e592406;hb=965fa6b0d9d99afbbef8b3fcb8066ce4136b8c35;hp=b6f56f05ec618306638353f16d757755261ddc6a;hpb=fb0c9d41d685abb58575c5482ca33b8cd457c5ec;p=ffmpeg

diff --git a/libavcodec/cabac.c b/libavcodec/cabac.c
index b6f56f05ec6..65579d8d3ba 100644
--- a/libavcodec/cabac.c
+++ b/libavcodec/cabac.c
@@ -2,20 +2,20 @@
  * H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
  * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
  *
- * This file is part of Libav.
+ * This file is part of FFmpeg.
  *
- * Libav is free software; you can redistribute it and/or
+ * 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.
  *
- * Libav is distributed in the hope that it will be useful,
+ * 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 Libav; if not, write to the Free Software
+ * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
@@ -27,6 +27,7 @@
 #include <string.h>
 
 #include "libavutil/common.h"
+#include "libavutil/timer.h"
 #include "get_bits.h"
 #include "cabac.h"
 #include "cabac_functions.h"
@@ -102,6 +103,19 @@ static const uint8_t last_coeff_flag_offset_8x8[63] = {
  5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8
 };
 
+/**
+ *
+ * @param buf_size size of buf in bits
+ */
+void ff_init_cabac_encoder(CABACContext *c, uint8_t *buf, int buf_size){
+    init_put_bits(&c->pb, buf, buf_size);
+
+    c->low= 0;
+    c->range= 0x1FE;
+    c->outstanding_count= 0;
+    c->pb.bit_left++; //avoids firstBitFlag
+}
+
 /**
  *
  * @param buf_size size of buf in bits
@@ -134,7 +148,6 @@ void ff_init_cabac_states(void)
             ff_h264_lps_range[j*2*64+2*i+0]=
             ff_h264_lps_range[j*2*64+2*i+1]= lps_range[i][j];
         }
-
         ff_h264_mlps_state[128 + 2 * i + 0] = 2 * mps_state[i] + 0;
         ff_h264_mlps_state[128 + 2 * i + 1] = 2 * mps_state[i] + 1;
 
@@ -152,3 +165,151 @@ void ff_init_cabac_states(void)
 
     initialized = 1;
 }
+
+#ifdef TEST
+#define SIZE 10240
+
+#include "libavutil/lfg.h"
+#include "avcodec.h"
+
+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;
+    }
+}
+
+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_mlps_state[128 + *state];
+    }else{
+        c->low += c->range - RangeLPS;
+        c->range = RangeLPS;
+        *state= ff_h264_mlps_state[127 - *state];
+    }
+
+    renorm_cabac_encoder(c);
+}
+
+/**
+ * @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;
+    }
+}
+
+/**
+ *
+ * @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);
+
+        av_assert0(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
+    }
+
+    return (put_bits_count(&c->pb)+7)>>3;
+}
+
+int main(void){
+    CABACContext c;
+    uint8_t b[9*SIZE];
+    uint8_t r[9*SIZE];
+    int i;
+    uint8_t state[10]= {0};
+    AVLFG prng;
+
+    av_lfg_init(&prng, 1);
+    ff_init_cabac_encoder(&c, b, SIZE);
+    ff_init_cabac_states();
+
+    for(i=0; i<SIZE; i++){
+        if(2*i<SIZE) r[i] = av_lfg_get(&prng) % 7;
+        else         r[i] = (i>>8)&1;
+    }
+
+    for(i=0; i<SIZE; i++){
+START_TIMER
+        put_cabac_bypass(&c, r[i]&1);
+STOP_TIMER("put_cabac_bypass")
+    }
+
+    for(i=0; i<SIZE; i++){
+START_TIMER
+        put_cabac(&c, state, r[i]&1);
+STOP_TIMER("put_cabac")
+    }
+
+    put_cabac_terminate(&c, 1);
+
+    ff_init_cabac_decoder(&c, b, SIZE);
+
+    memset(state, 0, sizeof(state));
+
+    for(i=0; i<SIZE; i++){
+START_TIMER
+        if( (r[i]&1) != get_cabac_bypass(&c) )
+            av_log(NULL, AV_LOG_ERROR, "CABAC bypass failure at %d\n", i);
+STOP_TIMER("get_cabac_bypass")
+    }
+
+    for(i=0; i<SIZE; i++){
+START_TIMER
+        if( (r[i]&1) != get_cabac_noinline(&c, state) )
+            av_log(NULL, AV_LOG_ERROR, "CABAC failure at %d\n", i);
+STOP_TIMER("get_cabac")
+    }
+    if(!get_cabac_terminate(&c))
+        av_log(NULL, AV_LOG_ERROR, "where's the Terminator?\n");
+
+    return 0;
+}
+
+#endif /* TEST */