Simplified deblocking checks.

Patch by Dark Shikari

Originally committed as revision 20751 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/vp3.c

@@ -1641,17 +1641,21 @@ static void apply_loop_filter(Vp3DecodeContext *s)
         for (y = 0; y < height; y++) {
 
             for (x = 0; x < width; x++) {
+                /* This code basically just deblocks on the edges of coded blocks.
+                 * However, it has to be much more complicated because of the
+                 * braindamaged deblock ordering used in VP3/Theora. Order matters
+                 * because some pixels get filtered twice. */
+                if( s->all_fragments[fragment].coding_method != MODE_COPY )
+                {
                 /* do not perform left edge filter for left columns frags */
-                if ((x > 0) &&
-                    (s->all_fragments[fragment].coding_method != MODE_COPY)) {
+                    if (x > 0) {
                     s->dsp.vp3_h_loop_filter(
                         plane_data + s->all_fragments[fragment].first_pixel,
                         stride, bounding_values);
                 }
 
                 /* do not perform top edge filter for top row fragments */
-                if ((y > 0) &&
-                    (s->all_fragments[fragment].coding_method != MODE_COPY)) {
+                    if (y > 0) {
                     s->dsp.vp3_v_loop_filter(
                         plane_data + s->all_fragments[fragment].first_pixel,
                         stride, bounding_values);
@@ -1661,7 +1665,6 @@ static void apply_loop_filter(Vp3DecodeContext *s)
                  * fragments or if right fragment neighbor is also coded
                  * in this frame (it will be filtered in next iteration) */
                 if ((x < width - 1) &&
-                    (s->all_fragments[fragment].coding_method != MODE_COPY) &&
                     (s->all_fragments[fragment + 1].coding_method == MODE_COPY)) {
                     s->dsp.vp3_h_loop_filter(
                         plane_data + s->all_fragments[fragment + 1].first_pixel,
@@ -1672,12 +1675,12 @@ static void apply_loop_filter(Vp3DecodeContext *s)
                  * fragments or if bottom fragment neighbor is also coded
                  * in this frame (it will be filtered in the next row) */
                 if ((y < height - 1) &&
-                    (s->all_fragments[fragment].coding_method != MODE_COPY) &&
                     (s->all_fragments[fragment + width].coding_method == MODE_COPY)) {
                     s->dsp.vp3_v_loop_filter(
                         plane_data + s->all_fragments[fragment + width].first_pixel,
                         stride, bounding_values);
                 }
+                }
 
                 fragment++;
             }