diff --git a/libavcodec/wmavoice.c b/libavcodec/wmavoice.c
index 444e303b0d..68bb65986e 100644
--- a/libavcodec/wmavoice.c
+++ b/libavcodec/wmavoice.c
@@ -1906,7 +1906,7 @@ static int wmavoice_decode_packet(AVCodecContext *ctx, void *data,
      * in a single "muxer" packet, so we artificially emulate that by
      * capping the packet size at ctx->block_align. */
     for (size = avpkt->size; size > ctx->block_align; size -= ctx->block_align);
-    init_get_bits(&s->gb, avpkt->data, size << 3);
+    init_get_bits8(&s->gb, avpkt->data, size);
 
     /* size == ctx->block_align is used to indicate whether we are dealing with
      * a new packet or a packet of which we already read the packet header