mjpeg: fix fliping with emu edges.

Fixes Ticket121
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/mjpegdec.c

@@ -967,11 +967,6 @@ static int mjpeg_decode_scan(MJpegDecodeContext *s, int nb_components, int Ah,
     if (mb_bitmask)
         init_get_bits(&mb_bitmask_gb, mb_bitmask, s->mb_width * s->mb_height);
 
-    if (s->flipped && s->avctx->flags & CODEC_FLAG_EMU_EDGE) {
-        av_log(s->avctx, AV_LOG_ERROR,
-               "Can not flip image with CODEC_FLAG_EMU_EDGE set!\n");
-        s->flipped = 0;
-    }
     if (s->flipped && s->avctx->lowres) {
         av_log(s->avctx, AV_LOG_ERROR, "Can not flip image with lowres\n");
         s->flipped = 0;
@@ -983,7 +978,7 @@ static int mjpeg_decode_scan(MJpegDecodeContext *s, int nb_components, int Ah,
         reference_data[c] = reference ? reference->data[c] : NULL;
         linesize[c] = s->linesize[c];
         s->coefs_finished[c] |= 1;
-        if (s->flipped) {
+        if (s->flipped && !(s->avctx->flags & CODEC_FLAG_EMU_EDGE)) {
             // picture should be flipped upside-down for this codec
             int offset = (linesize[c] * (s->v_scount[i] *
                          (8 * s->mb_height - ((s->height / s->v_max) & 7)) - 1));
@@ -1795,6 +1790,29 @@ the_end:
             dst -= s->linesize[s->upscale_v];
         }
     }
+    if (s->flipped && (s->avctx->flags & CODEC_FLAG_EMU_EDGE)) {
+        int hshift, vshift, j;
+        avcodec_get_chroma_sub_sample(s->avctx->pix_fmt, &hshift, &vshift);
+        for (index=0; index<4; index++) {
+            uint8_t *dst = s->picture_ptr->data[index];
+            int w = s->width;
+            int h = s->height;
+            if(index && index<3){
+                w = -((-w) >> hshift);
+                h = -((-h) >> vshift);
+            }
+            if(dst){
+                uint8_t *dst2 = dst + s->linesize[index]*(h-1);
+                for (i=0; i<h/2; i++) {
+                    for (j=0; j<w; j++)
+                        FFSWAP(int, dst[j], dst2[j]);
+                    dst  += s->linesize[index];
+                    dst2 -= s->linesize[index];
+                }
+            }
+        }
+    }
+
     av_log(avctx, AV_LOG_DEBUG, "decode frame unused %td bytes\n",
            buf_end - buf_ptr);
 //  return buf_end - buf_ptr;