Border processing adaptive quant patch by (Christophe Massiot |cmassiot freebox fr)

Originally committed as revision 3927 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/avcodec.h

@@ -17,7 +17,7 @@ extern "C" {
 
 #define FFMPEG_VERSION_INT     0x000409
 #define FFMPEG_VERSION         "0.4.9-pre1"
-#define LIBAVCODEC_BUILD       4740
+#define LIBAVCODEC_BUILD       4741
 
 #define LIBAVCODEC_VERSION_INT FFMPEG_VERSION_INT
 #define LIBAVCODEC_VERSION     FFMPEG_VERSION
@@ -1750,6 +1750,14 @@ typedef struct AVCodecContext {
      * - decoding: unused
      */
     int frame_skip_cmp;
+
+    /**
+     * border processing masking. raises the quantizer for mbs on the borders
+     * of the picture.
+     * - encoding: set by user
+     * - decoding: unused
+     */
+    float border_masking;
 } AVCodecContext;
 
 

libavcodec/mpegvideo.c

@@ -949,6 +949,7 @@ int MPV_encode_init(AVCodecContext *avctx)
                         || s->avctx->temporal_cplx_masking 
                         || s->avctx->spatial_cplx_masking
                         || s->avctx->p_masking
+                        || s->avctx->border_masking
                         || (s->flags&CODEC_FLAG_QP_RD))
                        && !s->fixed_qscale;
     

libavcodec/ratecontrol.c

@@ -501,6 +501,7 @@ static void adaptive_quantization(MpegEncContext *s, double q){
     const float temp_cplx_masking= s->avctx->temporal_cplx_masking;
     const float spatial_cplx_masking = s->avctx->spatial_cplx_masking;
     const float p_masking = s->avctx->p_masking;
+    const float border_masking = s->avctx->border_masking;
     float bits_sum= 0.0;
     float cplx_sum= 0.0;
     float cplx_tab[s->mb_num];
@@ -508,6 +509,8 @@ static void adaptive_quantization(MpegEncContext *s, double q){
     const int qmin= s->avctx->lmin;
     const int qmax= s->avctx->lmax;
     Picture * const pic= &s->current_picture;
+    const int mb_width = s->mb_width;
+    const int mb_height = s->mb_height;
     
     for(i=0; i<s->mb_num; i++){
         const int mb_xy= s->mb_index2xy[i];
@@ -515,6 +518,10 @@ static void adaptive_quantization(MpegEncContext *s, double q){
         float spat_cplx= sqrt(pic->mb_var[mb_xy]);
         const int lumi= pic->mb_mean[mb_xy];
         float bits, cplx, factor;
+        int mb_x = mb_xy % s->mb_stride;
+        int mb_y = mb_xy / s->mb_stride;
+        int mb_distance;
+        float mb_factor = 0.0;
 #if 0        
         if(spat_cplx < q/3) spat_cplx= q/3; //FIXME finetune
         if(temp_cplx < q/3) temp_cplx= q/3; //FIXME finetune
@@ -535,6 +542,23 @@ static void adaptive_quantization(MpegEncContext *s, double q){
             factor*= (1.0 - (lumi-128)*(lumi-128)*lumi_masking);
         else
             factor*= (1.0 - (lumi-128)*(lumi-128)*dark_masking);
+
+        if(mb_x < mb_width/5){
+            mb_distance = mb_width/5 - mb_x;
+            mb_factor = (float)mb_distance / (float)(mb_width/5);
+        }else if(mb_x > 4*mb_width/5){
+            mb_distance = mb_x - 4*mb_width/5;
+            mb_factor = (float)mb_distance / (float)(mb_width/5);
+        }
+        if(mb_y < mb_height/5){
+            mb_distance = mb_height/5 - mb_y;
+            mb_factor = FFMAX(mb_factor, (float)mb_distance / (float)(mb_height/5));
+        }else if(mb_y > 4*mb_height/5){
+            mb_distance = mb_y - 4*mb_height/5;
+            mb_factor = FFMAX(mb_factor, (float)mb_distance / (float)(mb_height/5));
+        }
+
+        factor*= 1.0 - border_masking*mb_factor;
         
         if(factor<0.00001) factor= 0.00001;