avcodec/mjpegdec: Support 31111100 sampling

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

libavcodec/mjpegdec.c

@@ -518,6 +518,13 @@ int ff_mjpeg_decode_sof(MJpegDecodeContext *s)
             s->avctx->color_range = s->cs_itu601 ? AVCOL_RANGE_MPEG : AVCOL_RANGE_JPEG;
         }
         break;
+    case 0x31111100:
+        if (s->bits > 8)
+            goto unk_pixfmt;
+        s->avctx->pix_fmt = s->cs_itu601 ? AV_PIX_FMT_YUV444P : AV_PIX_FMT_YUVJ444P;
+        s->avctx->color_range = s->cs_itu601 ? AVCOL_RANGE_MPEG : AVCOL_RANGE_JPEG;
+        s->upscale_h[1] = s->upscale_h[2] = 2;
+        break;
     case 0x22121100:
     case 0x22111200:
         if (s->bits <= 8) s->avctx->pix_fmt = s->cs_itu601 ? AV_PIX_FMT_YUV422P : AV_PIX_FMT_YUVJ422P;
@@ -2162,6 +2169,7 @@ the_end:
                 h = (h+1)>>1;
             av_assert0(w > 0);
             for (i = 0; i < h; i++) {
+                if (s->upscale_h[p] == 1) {
                     if (is16bit) ((uint16_t*)line)[w - 1] = ((uint16_t*)line)[(w - 1) / 2];
                     else                      line[w - 1] = line[(w - 1) / 2];
                     for (index = w - 2; index > 0; index--) {
@@ -2170,6 +2178,18 @@ the_end:
                         else
                             line[index] = (line[index / 2] + line[(index + 1) / 2]) >> 1;
                     }
+                } else if (s->upscale_h[p] == 2) {
+                    if (is16bit) {
+                        ((uint16_t*)line)[w - 1] =
+                        ((uint16_t*)line)[w - 2] = ((uint16_t*)line)[(w - 1) / 3];
+                    } else {
+                        line[w - 1] =
+                        line[w - 2] = line[(w - 1) / 3];
+                    }
+                    for (index = w - 3; index > 0; index--) {
+                        line[index] = (line[index / 3] + line[(index + 1) / 3] + line[(index + 2) / 3] + 1) / 3;
+                    }
+                }
                 line += s->linesize[p];
             }
         }