hevc: fix decoding of one PU wide files

For those the block size may be larger than the source linesize (if the
edges are not allocated).
Signed-off-by: Anton Khirnov <anton@khirnov.net>

libavcodec/hevc.c

@@ -1497,15 +1497,19 @@ static void luma_mc(HEVCContext *s, int16_t *dst, ptrdiff_t dststride,
     if (x_off < extra_left || y_off < extra_top ||
         x_off >= pic_width - block_w - ff_hevc_qpel_extra_after[mx] ||
         y_off >= pic_height - block_h - ff_hevc_qpel_extra_after[my]) {
+        const int edge_emu_stride = EDGE_EMU_BUFFER_STRIDE << s->sps->pixel_shift;
         int offset = extra_top * srcstride + (extra_left << s->sps->pixel_shift);
+        int buf_offset = extra_top *
+                         edge_emu_stride + (extra_left << s->sps->pixel_shift);
 
         s->vdsp.emulated_edge_mc(lc->edge_emu_buffer, src - offset,
-                                 srcstride, srcstride,
+                                 edge_emu_stride, srcstride,
                                  block_w + ff_hevc_qpel_extra[mx],
                                  block_h + ff_hevc_qpel_extra[my],
                                  x_off - extra_left, y_off - extra_top,
                                  pic_width, pic_height);
-        src = lc->edge_emu_buffer + offset;
+        src = lc->edge_emu_buffer + buf_offset;
+        srcstride = edge_emu_stride;
     }
     s->hevcdsp.put_hevc_qpel[my][mx](dst, dststride, src, srcstride, block_w,
                                      block_h, lc->mc_buffer);
@@ -1548,27 +1552,35 @@ static void chroma_mc(HEVCContext *s, int16_t *dst1, int16_t *dst2,
     if (x_off < EPEL_EXTRA_BEFORE || y_off < EPEL_EXTRA_AFTER ||
         x_off >= pic_width - block_w - EPEL_EXTRA_AFTER ||
         y_off >= pic_height - block_h - EPEL_EXTRA_AFTER) {
+        const int edge_emu_stride = EDGE_EMU_BUFFER_STRIDE << s->sps->pixel_shift;
         int offset1 = EPEL_EXTRA_BEFORE * (src1stride + (1 << s->sps->pixel_shift));
+        int buf_offset1 = EPEL_EXTRA_BEFORE *
+                          (edge_emu_stride + (1 << s->sps->pixel_shift));
         int offset2 = EPEL_EXTRA_BEFORE * (src2stride + (1 << s->sps->pixel_shift));
+        int buf_offset2 = EPEL_EXTRA_BEFORE *
+                          (edge_emu_stride + (1 << s->sps->pixel_shift));
 
         s->vdsp.emulated_edge_mc(lc->edge_emu_buffer, src1 - offset1,
-                                 src1stride, src1stride,
+                                 edge_emu_stride, src1stride,
                                  block_w + EPEL_EXTRA, block_h + EPEL_EXTRA,
                                  x_off - EPEL_EXTRA_BEFORE,
                                  y_off - EPEL_EXTRA_BEFORE,
                                  pic_width, pic_height);
 
-        src1 = lc->edge_emu_buffer + offset1;
+        src1 = lc->edge_emu_buffer + buf_offset1;
+        src1stride = edge_emu_stride;
         s->hevcdsp.put_hevc_epel[!!my][!!mx](dst1, dststride, src1, src1stride,
                                              block_w, block_h, mx, my, lc->mc_buffer);
 
         s->vdsp.emulated_edge_mc(lc->edge_emu_buffer, src2 - offset2,
-                                 src2stride, src2stride,
+                                 edge_emu_stride, src2stride,
                                  block_w + EPEL_EXTRA, block_h + EPEL_EXTRA,
                                  x_off - EPEL_EXTRA_BEFORE,
                                  y_off - EPEL_EXTRA_BEFORE,
                                  pic_width, pic_height);
-        src2 = lc->edge_emu_buffer + offset2;
+        src2 = lc->edge_emu_buffer + buf_offset2;
+        src2stride = edge_emu_stride;
+
         s->hevcdsp.put_hevc_epel[!!my][!!mx](dst2, dststride, src2, src2stride,
                                              block_w, block_h, mx, my,
                                              lc->mc_buffer);
@@ -2421,13 +2433,6 @@ static int hevc_frame_start(HEVCContext *s)
     if (ret < 0)
         goto fail;
 
-    av_fast_malloc(&lc->edge_emu_buffer, &lc->edge_emu_buffer_size,
-                   (MAX_PB_SIZE + 7) * s->ref->frame->linesize[0]);
-    if (!lc->edge_emu_buffer) {
-        ret = AVERROR(ENOMEM);
-        goto fail;
-    }
-
     ret = ff_hevc_frame_rps(s);
     if (ret < 0) {
         av_log(s->avctx, AV_LOG_ERROR, "Error constructing the frame RPS.\n");
@@ -2924,12 +2929,10 @@ fail:
 static av_cold int hevc_decode_free(AVCodecContext *avctx)
 {
     HEVCContext       *s = avctx->priv_data;
-    HEVCLocalContext *lc = &s->HEVClc;
     int i;
 
     pic_arrays_free(s);
 
-    av_freep(&lc->edge_emu_buffer);
     av_freep(&s->md5_ctx);
 
     av_frame_free(&s->tmp_frame);

libavcodec/hevc.h

@@ -71,6 +71,8 @@
 #define EPEL_EXTRA_AFTER  2
 #define EPEL_EXTRA        3
 
+#define EDGE_EMU_BUFFER_STRIDE 80
+
 /**
  * Value of the luma sample at position (x, y) in the 2D array tab.
  */
@@ -741,8 +743,8 @@ typedef struct HEVCLocalContext {
     int     start_of_tiles_x;
     int     end_of_tiles_x;
     int     end_of_tiles_y;
-    uint8_t *edge_emu_buffer;
-    int      edge_emu_buffer_size;
+    /* +7 is for subpixel interpolation, *2 for high bit depths */
+    DECLARE_ALIGNED(32, uint8_t, edge_emu_buffer)[(MAX_PB_SIZE + 7) * EDGE_EMU_BUFFER_STRIDE * 2];
     CodingTree ct;
     CodingUnit cu;
     PredictionUnit pu;