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

libavcodec/avcodec.h

@@ -15,8 +15,8 @@ extern "C" {
 
 #define LIBAVCODEC_VERSION_INT 0x000406
 #define LIBAVCODEC_VERSION     "0.4.6"
-#define LIBAVCODEC_BUILD       4668
-#define LIBAVCODEC_BUILD_STR   "4668"
+#define LIBAVCODEC_BUILD       4669
+#define LIBAVCODEC_BUILD_STR   "4669"
 
 #define LIBAVCODEC_IDENT	"FFmpeg" LIBAVCODEC_VERSION "b" LIBAVCODEC_BUILD_STR
 
@@ -1127,6 +1127,22 @@ typedef struct AVCodecContext {
      * - decoding: unused
      */
     int global_quality;
+    
+#define FF_CODER_TYPE_VLC   0
+#define FF_CODER_TYPE_AC    1
+    /**
+     * coder type
+     * - encoding: set by user.
+     * - decoding: unused
+     */
+    int coder_type;
+
+    /**
+     * context model
+     * - encoding: set by user.
+     * - decoding: unused
+     */
+    int context_model;
 } AVCodecContext;
 
 

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);
+    }
+}