@@ -653,6 +653,7 @@ static int tiff_unpack_strip(TiffContext *s, AVFrame *p, uint8_t *dst, int strid

 static int init_image(TiffContext *s, ThreadFrame *frame)

 {

     int ret;

+    int create_gray_palette = 0;

     switch (s->planar * 1000 + s->bpp * 10 + s->bppcount) {

     case 11:

@@ -662,6 +663,11 @@ static int init_image(TiffContext *s, ThreadFrame *frame)

         }

     case 21:

     case 41:

+        s->avctx->pix_fmt = AV_PIX_FMT_PAL8;

+        if (!s->palette_is_set) {

+            create_gray_palette = 1;

+        }

+        break;

     case 81:

         s->avctx->pix_fmt = s->palette_is_set ? AV_PIX_FMT_PAL8 : AV_PIX_FMT_GRAY8;

         break;

@@ -741,7 +747,15 @@ static int init_image(TiffContext *s, ThreadFrame *frame)

     if ((ret = ff_thread_get_buffer(s->avctx, frame, 0)) < 0)

         return ret;

     if (s->avctx->pix_fmt == AV_PIX_FMT_PAL8) {

-        memcpy(frame->f->data[1], s->palette, sizeof(s->palette));

+        if (!create_gray_palette)

+            memcpy(frame->f->data[1], s->palette, sizeof(s->palette));

+        else {

+            /* make default grayscale pal */

+            int i;

+            uint32_t *pal = (uint32_t *)frame->f->data[1];

+            for (i = 0; i < 1<<s->bpp; i++)

+                pal[i] = 0xFFU << 24 | i * 255 / ((1<<s->bpp) - 1) * 0x010101;

+        }

     }

     return 0;

 }