fix for missing NULL check in BKE_sequence_init_colorspace().

source/blender/blenkernel/intern/sequencer.c

@@ -3967,15 +3967,15 @@ void BKE_sequence_init_colorspace(Sequence *seq)
 			/* byte images are default to straight alpha, however sequencer
 			 * works in premul space, so mark strip to be premultiplied first
 			 */
-			if (!ibuf->rect_float)
-				seq->alpha_mode = SEQ_ALPHA_STRAIGHT;
-			else
 			seq->alpha_mode = SEQ_ALPHA_PREMUL;
-
-			if (ibuf)
+			if (ibuf) {
+				if (ibuf->rect_float) {
+					seq->alpha_mode = SEQ_ALPHA_PREMUL;
+				}
 				IMB_freeImBuf(ibuf);
 			}
 		}
+	}
 }
 
 /* NOTE: this function doesn't fill in image names */