diff --git a/trunk/src/kernel/srs_kernel_codec.cpp b/trunk/src/kernel/srs_kernel_codec.cpp
index 8a2f5cb89..53bb44abf 100644
--- a/trunk/src/kernel/srs_kernel_codec.cpp
+++ b/trunk/src/kernel/srs_kernel_codec.cpp
@@ -1040,11 +1040,6 @@ int SrsAvcAacCodec::avc_demux_sps_rbsp(char* rbsp, int nb_rbsp)
                 if ((ret = srs_avc_nalu_read_bit(&bs, seq_scaling_matrix_present_flag_i)) != ERROR_SUCCESS) {
                     return ret;
                 }
-                if (seq_scaling_matrix_present_flag_i) {
-                    ret = ERROR_HLS_DECODE_ERROR;
-                    srs_error("sps the seq_scaling_matrix_present_flag invalid, i=%d, nb_scmpfs=%d. ret=%d", i, nb_scmpfs, ret);
-                    return ret;
-                }
             }
         }
     }
@@ -1084,11 +1079,17 @@ int SrsAvcAacCodec::avc_demux_sps_rbsp(char* rbsp, int nb_rbsp)
         if ((ret = srs_avc_nalu_read_uev(&bs, num_ref_frames_in_pic_order_cnt_cycle)) != ERROR_SUCCESS) {
             return ret;
         }
-        if (num_ref_frames_in_pic_order_cnt_cycle) {
+        if (num_ref_frames_in_pic_order_cnt_cycle < 0) {
             ret = ERROR_HLS_DECODE_ERROR;
             srs_error("sps the num_ref_frames_in_pic_order_cnt_cycle invalid. ret=%d", ret);
             return ret;
         }
+        for (int i = 0; i < num_ref_frames_in_pic_order_cnt_cycle; i++) {
+            int32_t offset_for_ref_frame_i = -1;
+            if ((ret = srs_avc_nalu_read_uev(&bs, offset_for_ref_frame_i)) != ERROR_SUCCESS) {
+                return ret;
+            }
+        }
     }
     
     int32_t max_num_ref_frames = -1;
diff --git a/trunk/src/kernel/srs_kernel_utility.cpp b/trunk/src/kernel/srs_kernel_utility.cpp
index e6bd81cc9..d5e15cd54 100644
--- a/trunk/src/kernel/srs_kernel_utility.cpp
+++ b/trunk/src/kernel/srs_kernel_utility.cpp
@@ -77,7 +77,7 @@ int srs_avc_nalu_read_uev(SrsBitBuffer* stream, int32_t& v)
     v = (1 << leadingZeroBits) - 1;
     for (int i = 0; i < leadingZeroBits; i++) {
         int32_t b = stream->read_bit();
-        v += b << (leadingZeroBits - 1);
+        v += b << (leadingZeroBits - 1 - i);
     }
     
     return ret;