golomb rice codes

use gradients instead of prediction errors as context model
store independant quantization tables for each point
merge contexts with opposit sign

Originally committed as revision 1957 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 50 insertions, 0 deletions

diff --git a/libavcodec/golomb.h b/libavcodec/golomb.h
index f1e6d6d987..9861b18d1a 100644
--- a/libavcodec/golomb.h
+++ b/libavcodec/golomb.h
@@ -178,6 +178,37 @@ static inline int svq3_get_se_golomb(GetBitContext *gb){
     }
 }
 
+/**
+ * read unsigned golomb rice code.
+ */
+static inline int get_ur_golomb(GetBitContext *gb, int k, int limit, int esc_len){
+    unsigned int buf;
+    int log;
+    
+    OPEN_READER(re, gb);
+    UPDATE_CACHE(re, gb);
+    buf=GET_CACHE(re, gb);
+
+    log= av_log2(buf);
+//printf("buf:%X log:%d\n", buf, log);
+    if(log > 31-limit){
+        buf >>= log - k;
+        buf += (30-log)<<k;
+        LAST_SKIP_BITS(re, gb, 32 + k - log);
+        CLOSE_READER(re, gb);
+    
+        return buf;
+    }else if(log == 31-limit){
+        buf >>= log - esc_len;
+        buf -= 1<<esc_len;
+        LAST_SKIP_BITS(re, gb, esc_len + limit + 1);
+        CLOSE_READER(re, gb);
+    
+        return buf + 1;
+    }else
+        return -1;
+}
+
 #ifdef TRACE
 
 static inline int get_ue(GetBitContext *s, char *file, char *func, int line){
@@ -279,3 +310,22 @@ static inline void set_se_golomb(PutBitContext *pb, int i){
 #endif
     set_ue_golomb(pb, i);
 }
+
+/**
+ * write unsigned golomb rice code.
+ */
+static inline void set_ur_golomb(PutBitContext *pb, int i, int k, int limit, int esc_len){
+    int e;
+    
+    assert(i>=0);
+    
+    e= i>>k;
+    if(e<limit){
+        put_bits(pb, e + k + 1, (1<<k) + (i&((1<<k)-1)));
+    }else{
+//    printf("set %08X, %d\n", (1<<esc_len) + i - 1, limit + esc_len + 1); 
+        put_bits(pb, limit + esc_len + 1, (1<<esc_len) + i - 1);
+//        put_bits(pb, 1, limit + 1);
+//        put_bits(pb, i - 1, esc_len);
+    }
+}