intrax8: Use local destination buffers

These buffers are just a way to store frame pointers and be able to
modify them without touching the original ones.

The two dependent decoders (WMV2 and VC1) do not need special care for
these fields: the former does not seem to use the dest buffers, while
the latter reinits them every time to the current frame data buffers.

So only keep a local copy rather than the one from mpegvideo.

libavcodec/intrax8.c

@@ -335,7 +335,7 @@ static int x8_setup_spatial_predictor(IntraX8Context *const w, const int chroma)
     int sum;
     int quant;
 
-    w->dsp.setup_spatial_compensation(s->dest[chroma], s->sc.edge_emu_buffer,
+    w->dsp.setup_spatial_compensation(w->dest[chroma], s->sc.edge_emu_buffer,
                                       s->current_picture.f->linesize[chroma > 0],
                                       &range, &sum, w->edges);
     if (chroma) {
@@ -671,7 +671,7 @@ static int x8_decode_intra_mb(IntraX8Context *const w, const int chroma)
             dc_level += (w->predicted_dc * divide_quant + (1 << 12)) >> 13;
 
             dsp_x8_put_solidcolor(av_clip_uint8((dc_level * dc_quant + 4) >> 3),
-                                  s->dest[chroma],
+                                  w->dest[chroma],
                                   s->current_picture.f->linesize[!!chroma]);
 
             goto block_placed;
@@ -696,15 +696,15 @@ static int x8_decode_intra_mb(IntraX8Context *const w, const int chroma)
     }
 
     if (w->flat_dc) {
-        dsp_x8_put_solidcolor(w->predicted_dc, s->dest[chroma],
+        dsp_x8_put_solidcolor(w->predicted_dc, w->dest[chroma],
                               s->current_picture.f->linesize[!!chroma]);
     } else {
         w->dsp.spatial_compensation[w->orient](s->sc.edge_emu_buffer,
-                                               s->dest[chroma],
+                                               w->dest[chroma],
                                                s->current_picture.f->linesize[!!chroma]);
     }
     if (!zeros_only)
-        s->idsp.idct_add(s->dest[chroma],
+        s->idsp.idct_add(w->dest[chroma],
                          s->current_picture.f->linesize[!!chroma],
                          s->block[0]);
 
@@ -713,7 +713,7 @@ block_placed:
         x8_update_predictions(w, w->orient, n);
 
     if (s->loop_filter) {
-        uint8_t *ptr = s->dest[chroma];
+        uint8_t *ptr = w->dest[chroma];
         int linesize = s->current_picture.f->linesize[!!chroma];
 
         if (!((w->edges & 2) || (zeros_only && (w->orient | 4) == 4)))
@@ -726,21 +726,22 @@ block_placed:
 }
 
 // FIXME maybe merge with ff_*
-static void x8_init_block_index(MpegEncContext *s)
+static void x8_init_block_index(IntraX8Context *w)
 {
+    MpegEncContext *const s = w->s;
     // not s->linesize as this would be wrong for field pics
     // not that IntraX8 has interlacing support ;)
     const int linesize   = s->current_picture.f->linesize[0];
     const int uvlinesize = s->current_picture.f->linesize[1];
 
-    s->dest[0] = s->current_picture.f->data[0];
-    s->dest[1] = s->current_picture.f->data[1];
-    s->dest[2] = s->current_picture.f->data[2];
+    w->dest[0] = s->current_picture.f->data[0];
+    w->dest[1] = s->current_picture.f->data[1];
+    w->dest[2] = s->current_picture.f->data[2];
 
-    s->dest[0] +=  s->mb_y         * linesize   << 3;
+    w->dest[0] +=  s->mb_y         * linesize   << 3;
     // chroma blocks are on add rows
-    s->dest[1] += (s->mb_y & (~1)) * uvlinesize << 2;
-    s->dest[2] += (s->mb_y & (~1)) * uvlinesize << 2;
+    w->dest[1] += (s->mb_y & (~1)) * uvlinesize << 2;
+    w->dest[2] += (s->mb_y & (~1)) * uvlinesize << 2;
 }
 
 av_cold int ff_intrax8_common_init(IntraX8Context *w, MpegEncContext *const s)
@@ -796,7 +797,7 @@ int ff_intrax8_decode_picture(IntraX8Context *const w, int dquant,
     x8_reset_vlc_tables(w);
 
     for (s->mb_y = 0; s->mb_y < s->mb_height * 2; s->mb_y++) {
-        x8_init_block_index(s);
+        x8_init_block_index(w);
         mb_xy = (s->mb_y >> 1) * s->mb_stride;
 
         for (s->mb_x = 0; s->mb_x < s->mb_width * 2; s->mb_x++) {
@@ -819,8 +820,8 @@ int ff_intrax8_decode_picture(IntraX8Context *const w, int dquant,
                 if (x8_decode_intra_mb(w, 2))
                     goto error;
 
-                s->dest[1] += 8;
-                s->dest[2] += 8;
+                w->dest[1] += 8;
+                w->dest[2] += 8;
 
                 /* emulate MB info in the relevant tables */
                 s->mbskip_table[mb_xy]                 = 0;
@@ -828,7 +829,7 @@ int ff_intrax8_decode_picture(IntraX8Context *const w, int dquant,
                 s->current_picture.qscale_table[mb_xy] = w->quant;
                 mb_xy++;
             }
-            s->dest[0] += 8;
+            w->dest[0] += 8;
         }
         if (s->mb_y & 1)
             ff_mpeg_draw_horiz_band(s, (s->mb_y - 1) * 8, 16);

libavcodec/intrax8.h

@@ -45,6 +45,7 @@ typedef struct IntraX8Context {
     int quant_dc_chroma;
     int divide_quant_dc_luma;
     int divide_quant_dc_chroma;
+    uint8_t *dest[3];
 
     // changed per block
     int edges;