[FFmpeg-soc] [soc]: r4902 - wmapro/wmaprodec.c

[faust3]

Author: faust3
Date: Sun Aug  2 12:21:08 2009
New Revision: 4902

Log:
simplify handling of resampled scale factors

Modified:
   wmapro/wmaprodec.c

Modified: wmapro/wmaprodec.c
==============================================================================
--- wmapro/wmaprodec.c	Sun Aug  2 11:43:13 2009	(r4901)
+++ wmapro/wmaprodec.c	Sun Aug  2 12:21:08 2009	(r4902)
@@ -139,7 +139,7 @@ typedef struct {
     int8_t   scale_factor_step;                       ///< scaling step for the current subframe
     int      max_scale_factor;                        ///< maximum scale factor for the current subframe
     int      scale_factors[MAX_BANDS];                ///< scale factor values for the current subframe
-    int      resampled_scale_factors[MAX_BANDS];      ///< scale factors from a previous subframe
+    int      saved_scale_factors[MAX_BANDS];          ///< scale factors from a previous subframe
     int16_t  scale_factor_block_len;                  ///< scale factor reference block length
     float*   coeffs;                                  ///< pointer to the subframe decode buffer
     DECLARE_ALIGNED_16(float, out[2*WMAPRO_BLOCK_MAX_SIZE]); ///< output buffer
@@ -924,17 +924,8 @@ static int decode_scale_factors(WMA3Deco
                                MAX_BANDS  * idx0 + MAX_BANDS * idx1];
             int b;
             for (b=0;b<s->num_bands;b++)
-                s->channel[c].resampled_scale_factors[b] =
-                                   s->channel[c].scale_factors[*sf_offsets++];
-
-            s->channel[c].max_scale_factor =
-                                   s->channel[c].resampled_scale_factors[0];
-            sf = s->channel[c].resampled_scale_factors + 1;
-            while (sf < s->channel[c].resampled_scale_factors + s->num_bands) {
-                if (*sf > s->channel[c].max_scale_factor)
-                    s->channel[c].max_scale_factor = *sf;
-                ++sf;
-            }
+                s->channel[c].scale_factors[b] =
+                                   s->channel[c].saved_scale_factors[*sf_offsets++];
         }
 
         if (s->channel[c].cur_subframe > 0) {
@@ -956,11 +947,6 @@ static int decode_scale_factors(WMA3Deco
             } else {
                 int i;
                 /** run level decode differences to the resampled factors */
-
-                memcpy(s->channel[c].scale_factors,
-                       s->channel[c].resampled_scale_factors,
-                       sizeof(int) * s->num_bands);
-
                 for (i=0;i<s->num_bands;i++) {
                     int idx;
                     int skip;
@@ -992,14 +978,22 @@ static int decode_scale_factors(WMA3Deco
                 }
             }
 
-            s->channel[c].reuse_sf = 1;
-            s->channel[c].max_scale_factor = s->channel[c].scale_factors[0];
-            for (sf=s->channel[c].scale_factors + 1; sf < sf_end; sf++) {
-                if (s->channel[c].max_scale_factor < *sf)
-                    s->channel[c].max_scale_factor = *sf;
-            }
+            /** save transmitted scale factors so that they can be reused for
+                the next subframe */
+            memcpy(s->channel[c].saved_scale_factors,
+                   s->channel[c].scale_factors,
+                   sizeof(int) * s->num_bands);
             s->channel[c].scale_factor_block_len = s->subframe_len;
+            s->channel[c].reuse_sf = 1;
+        }
+
+        /** calculate new scale factor maximum */
+        s->channel[c].max_scale_factor = s->channel[c].scale_factors[0];
+        for (sf=s->channel[c].scale_factors + 1; sf < sf_end; sf++) {
+            if (s->channel[c].max_scale_factor < *sf)
+                s->channel[c].max_scale_factor = *sf;
         }
+
     }
     return 0;
 }
@@ -1286,14 +1280,9 @@ static int decode_subframe(WMA3DecodeCon
         inverse_channel_transform(s);
         for (i=0;i<s->channels_for_cur_subframe;i++) {
             int c = s->channel_indexes_for_cur_subframe[i];
-            int* sf;
+            const int* sf = s->channel[c].scale_factors;
             int b;
 
-            if (s->channel[c].transmit_sf) {
-                sf = s->channel[c].scale_factors;
-            } else
-                sf = s->channel[c].resampled_scale_factors;
-
             if (c == s->lfe_channel)
                 memset(&s->tmp[s->cur_subwoofer_cutoff],0,
                      sizeof(float) * (subframe_len - s->cur_subwoofer_cutoff));
@@ -1411,8 +1400,6 @@ static int decode_frame(WMA3DecodeContex
         s->channel[i].max_scale_factor = 0;
         memset(s->channel[i].scale_factors, 0,
                sizeof(s->channel[i].scale_factors));
-        memset(s->channel[i].resampled_scale_factors, 0,
-               sizeof(s->channel[i].resampled_scale_factors));
     }
 
     /** decode all subframes */