ffv1: fix plane_count at version 1.4

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

libavcodec/ffv1dec.c

@@ -499,7 +499,7 @@ static int read_extra_header(FFV1Context *f)
     f->chroma_h_shift             = get_symbol(c, state, 0);
     f->chroma_v_shift             = get_symbol(c, state, 0);
     f->transparency               = get_rac(c, state);
-    f->plane_count                = 2 + f->transparency;
+    f->plane_count                = 1 + (f->chroma_planes || f->version<4) + f->transparency;
     f->num_h_slices               = 1 + get_symbol(c, state, 0);
     f->num_v_slices               = 1 + get_symbol(c, state, 0);
 

libavcodec/ffv1enc.c

@@ -797,6 +797,9 @@ static av_cold int encode_init(AVCodecContext *avctx)
 
     if (!s->transparency)
         s->plane_count = 2;
+    if (!s->chroma_planes && s->version > 3)
+        s->plane_count--;
+
     avcodec_get_chroma_sub_sample(avctx->pix_fmt, &s->chroma_h_shift, &s->chroma_v_shift);
     s->picture_number = 0;