ffv1: fix packed rgb with 1.3

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

libavcodec/ffv1.c

@@ -1237,7 +1237,11 @@ static int encode_slice(AVCodecContext *c, void *arg){
     int x= fs->slice_x;
     int y= fs->slice_y;
     AVFrame * const p= &f->picture;
-    const int ps= (f->bits_per_raw_sample>8)+1;
+    const int ps= (av_pix_fmt_desc_get(c->pix_fmt)->flags & PIX_FMT_PLANAR)
+                        ?
+                    (f->bits_per_raw_sample>8)+1
+                        :
+                    4;
 
     if(p->key_frame)
         clear_slice_state(f, fs);
@@ -1657,7 +1661,11 @@ static int decode_slice(AVCodecContext *c, void *arg){
     FFV1Context *fs= *(void**)arg;
     FFV1Context *f= fs->avctx->priv_data;
     int width, height, x, y;
-    const int ps= (c->bits_per_raw_sample>8)+1;
+    const int ps= (av_pix_fmt_desc_get(c->pix_fmt)->flags & PIX_FMT_PLANAR)
+                        ?
+                    (c->bits_per_raw_sample>8)+1
+                        :
+                    4;
     AVFrame * const p= &f->picture;
 
     if(f->version > 2){