diff --git a/libavcodec/cavsdec.c b/libavcodec/cavsdec.c
index bc1ed60bf0..b6dd5f2d3f 100644
--- a/libavcodec/cavsdec.c
+++ b/libavcodec/cavsdec.c
@@ -1266,10 +1266,11 @@ static int cavs_decode_frame(AVCodecContext *avctx, AVFrame *rframe,
                 av_log(h->avctx, AV_LOG_WARNING, "no frame decoded\n");
             return FFMAX(0, buf_ptr - buf);
         }
-        input_size = (buf_end - buf_ptr) * 8;
+        input_size = buf_end - buf_ptr;
+        if ((ret = init_get_bits8(&h->gb, buf_ptr, input_size)) < 0)
+            return ret;
         switch (stc) {
         case CAVS_START_CODE:
-            init_get_bits(&h->gb, buf_ptr, input_size);
             decode_seq_header(h);
             break;
         case PIC_I_START_CODE:
@@ -1288,7 +1289,6 @@ static int cavs_decode_frame(AVCodecContext *avctx, AVFrame *rframe,
             *got_frame = 0;
             if (!h->got_keyframe)
                 break;
-            init_get_bits(&h->gb, buf_ptr, input_size);
             h->stc = stc;
             if (decode_pic(h))
                 break;
@@ -1312,7 +1312,6 @@ static int cavs_decode_frame(AVCodecContext *avctx, AVFrame *rframe,
             break;
         default:
             if (stc <= SLICE_MAX_START_CODE) {
-                init_get_bits(&h->gb, buf_ptr, input_size);
                 decode_slice_header(h, &h->gb);
             }
             break;