[FFmpeg-soc] [soc]: r4346 - in wmapro: wma3.h wma3dec.c

[faust3]

Author: faust3
Date: Sat May 30 22:36:24 2009
New Revision: 4346

Log:
use a sine table when calculating the decorrelation matrix

Modified:
   wmapro/wma3.h
   wmapro/wma3dec.c

Modified: wmapro/wma3.h
==============================================================================
--- wmapro/wma3.h	Sat May 30 21:22:28 2009	(r4345)
+++ wmapro/wma3.h	Sat May 30 22:36:24 2009	(r4346)
@@ -93,6 +93,7 @@ typedef struct WMA3DecodeContext {
     MDCTContext      mdct_ctx[BLOCK_NB_SIZES];      ///< MDCT context per block size
     DECLARE_ALIGNED_16(float, tmp[BLOCK_MAX_SIZE]); ///< imdct output buffer
     float*           windows[BLOCK_NB_SIZES];       ///< window per block size
+    float            sin64[33];                     ///< sinus table for decorrelation
     VLC              sf_vlc;                        ///< scale factor dpcm vlc
     VLC              sf_rl_vlc;                     ///< scale factor run length vlc
     VLC              vec4_vlc;                      ///< 4 coefficients per symbol

Modified: wmapro/wma3dec.c
==============================================================================
--- wmapro/wma3dec.c	Sat May 30 21:22:28 2009	(r4345)
+++ wmapro/wma3dec.c	Sat May 30 22:36:24 2009	(r4346)
@@ -432,6 +432,10 @@ static av_cold int wma_decode_init(AVCod
         }
     }
 
+    /** calculate sine values for the decorrelation matrix */
+    for(i=0;i<33;i++)
+        s->sin64[i] = sin(i*M_PI / 64.0);
+
     wma_dump_context(s);
     avctx->channel_layout = channel_mask;
     return 0;
@@ -644,11 +648,19 @@ static void wma_decode_decorrelation_mat
                 float v1 = tmp1[y];
                 float v2 = tmp2[y];
                 int n = rotation_offset[offset + x];
-                float cosv = sin(n*M_PI / 64.0);                // FIXME: use one table for this
-                float sinv = -cos(n*M_PI / 64.0);
+                float sinv;
+                float cosv;
 
-                chgroup->decorrelation_matrix[y + x * chgroup->num_channels] = (v1 * cosv) + (v2 * sinv);
-                chgroup->decorrelation_matrix[y + i * chgroup->num_channels] = (v1 * -sinv) + (v2 * cosv);
+                if(n<32){
+                    sinv = s->sin64[n];
+                    cosv = s->sin64[32-n];
+                }else{
+                    sinv = s->sin64[64-n];
+                    cosv = -s->sin64[n-32];
+                }
+
+                chgroup->decorrelation_matrix[y + x * chgroup->num_channels] = (v1 * sinv) - (v2 * cosv);
+                chgroup->decorrelation_matrix[y + i * chgroup->num_channels] = (v1 * cosv) + (v2 * sinv);
             }
         }
         offset += i;