diff --git a/libavcodec/wma.c b/libavcodec/wma.c
index bed47ec35bdb64cc80cf11bbd87e1e4175544d9c..4cdffcd1013e9e17df085c23440ac8e17397e1ec 100644
--- a/libavcodec/wma.c
+++ b/libavcodec/wma.c
@@ -137,6 +137,9 @@ int ff_wma_init(AVCodecContext *avctx, int flags2)
 
     /* compute MDCT block size */
     s->frame_len_bits = ff_wma_get_frame_len_bits(s->sample_rate, s->version, 0);
+    s->next_block_len_bits = s->frame_len_bits;
+    s->prev_block_len_bits = s->frame_len_bits;
+    s->block_len_bits      = s->frame_len_bits;
 
     s->frame_len = 1 << s->frame_len_bits;
     if (s->use_variable_block_len) {