avcodec/lcldec: mark output frames as keyframes

Signed-off-by: Paul B Mahol <onemda@gmail.com>

libavcodec/lcldec.c

@@ -460,6 +460,9 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPac
         return AVERROR_INVALIDDATA;
     }
 
+    frame->key_frame = 1;
+    frame->pict_type = AV_PICTURE_TYPE_I;
+
     *got_frame = 1;
 
     /* always report that the buffer was completely consumed */