minor simplifications in cabac_mb_type

[ffmpeg] / libavcodec / resample2.c

diff --git a/libavcodec/resample2.c b/libavcodec/resample2.c
index c41f6e13a25dd1e11bc791da597cf36fae503502..735f612d1624fe65ce9c6a3f2d065fe6399cc53d 100644 (file)
--- a/libavcodec/resample2.c
+++ b/libavcodec/resample2.c
@@ -14,10 +14,10 @@
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  *
  */
- 
+
 /**
  * @file resample2.c
  * audio resampling
@@ -66,7 +66,7 @@ double bessel(double x){
     double v=1;
     double t=1;
     int i;
-    
+
     for(i=1; i<50; i++){
         t *= i;
         v += pow(x*x/4, i)/(t*t);
@@ -134,14 +134,12 @@ AVResampleContext *av_resample_init(int out_rate, int in_rate, int filter_size,
     AVResampleContext *c= av_mallocz(sizeof(AVResampleContext));
     double factor= FFMIN(out_rate * cutoff / in_rate, 1.0);
     int phase_count= 1<<phase_shift;
-    
-    memset(c, 0, sizeof(AVResampleContext));
-    
+
     c->phase_shift= phase_shift;
     c->phase_mask= phase_count-1;
     c->linear= linear;
 
-    c->filter_length= ceil(filter_size/factor);
+    c->filter_length= FFMAX((int)ceil(filter_size/factor), 1);
     c->filter_bank= av_mallocz(c->filter_length*(phase_count+1)*sizeof(FELEM));
     av_build_filter(c->filter_bank, factor, c->filter_length, phase_count, 1<<FILTER_SHIFT, 1);
     memcpy(&c->filter_bank[c->filter_length*phase_count+1], c->filter_bank, (c->filter_length-1)*sizeof(FELEM));
@@ -159,6 +157,18 @@ void av_resample_close(AVResampleContext *c){
     av_freep(&c);
 }
 
+/**
+ * Compensates samplerate/timestamp drift. The compensation is done by changing
+ * the resampler parameters, so no audible clicks or similar distortions ocur
+ * @param compensation_distance distance in output samples over which the compensation should be performed
+ * @param sample_delta number of output samples which should be output less
+ *
+ * example: av_resample_compensate(c, 10, 500)
+ * here instead of 510 samples only 500 samples would be output
+ *
+ * note, due to rounding the actual compensation might be slightly different,
+ * especially if the compensation_distance is large and the in_rate used during init is small
+ */
 void av_resample_compensate(AVResampleContext *c, int sample_delta, int compensation_distance){
 //    sample_delta += (c->ideal_dst_incr - c->dst_incr)*(int64_t)c->compensation_distance / c->ideal_dst_incr;
     c->compensation_distance= compensation_distance;
@@ -181,12 +191,26 @@ int av_resample(AVResampleContext *c, short *dst, short *src, int *consumed, int
     int dst_incr_frac= c->dst_incr % c->src_incr;
     int dst_incr=      c->dst_incr / c->src_incr;
     int compensation_distance= c->compensation_distance;
-    
+
+  if(compensation_distance == 0 && c->filter_length == 1 && c->phase_shift==0){
+        int64_t index2= ((int64_t)index)<<32;
+        int64_t incr= (1LL<<32) * c->dst_incr / c->src_incr;
+        dst_size= FFMIN(dst_size, (src_size-1-index) * (int64_t)c->src_incr / c->dst_incr);
+
+        for(dst_index=0; dst_index < dst_size; dst_index++){
+            dst[dst_index] = src[index2>>32];
+            index2 += incr;
+        }
+        frac += dst_index * dst_incr_frac;
+        index += dst_index * dst_incr;
+        index += frac / c->src_incr;
+        frac %= c->src_incr;
+  }else{
     for(dst_index=0; dst_index < dst_size; dst_index++){
         FELEM *filter= c->filter_bank + c->filter_length*(index & c->phase_mask);
         int sample_index= index >> c->phase_shift;
         FELEM2 val=0;
-                
+
         if(sample_index < 0){
             for(i=0; i<c->filter_length; i++)
                 val += src[ABS(sample_index + i) % src_size] * filter[i];
@@ -222,6 +246,7 @@ int av_resample(AVResampleContext *c, short *dst, short *src, int *consumed, int
             dst_incr=      c->ideal_dst_incr / c->src_incr;
         }
     }
+  }
     *consumed= FFMAX(index, 0) >> c->phase_shift;
     if(index>=0) index &= c->phase_mask;
 
@@ -235,13 +260,13 @@ int av_resample(AVResampleContext *c, short *dst, short *src, int *consumed, int
         c->dst_incr= dst_incr_frac + c->src_incr*dst_incr;
         c->compensation_distance= compensation_distance;
     }
-#if 0    
+#if 0
     if(update_ctx && !c->compensation_distance){
 #undef rand
         av_resample_compensate(c, rand() % (8000*2) - 8000, 8000*2);
 av_log(NULL, AV_LOG_DEBUG, "%d %d %d\n", c->dst_incr, c->ideal_dst_incr, c->compensation_distance);
     }
 #endif
-    
+
     return dst_index;
 }