diff --git a/speechx/speechx/frontend/feature_cache.h b/speechx/speechx/frontend/feature_cache.h
index c7d66251..5849cc5c 100644
--- a/speechx/speechx/frontend/feature_cache.h
+++ b/speechx/speechx/frontend/feature_cache.h
@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#pragma once
+
 #include "base/common.h"
 #include "frontend/feature_extractor_interface.h"
 
@@ -45,4 +47,4 @@ class FeatureCache : public FeatureExtractorInterface {
     //    DISALLOW_COPY_AND_ASSGIN(FeatureCache);
 };
 
-}  // namespace ppspeech
\ No newline at end of file
+}  // namespace ppspeech
diff --git a/speechx/speechx/frontend/raw_audio.cc b/speechx/speechx/frontend/raw_audio.cc
index 0c7f4d21..1e265a57 100644
--- a/speechx/speechx/frontend/raw_audio.cc
+++ b/speechx/speechx/frontend/raw_audio.cc
@@ -35,7 +35,6 @@ void RawAudioSource::AcceptWaveform(const VectorBase<BaseFloat>& data) {
         ring_buffer_[idx % ring_buffer_.size()] = data(idx);
     }
     data_length_ += data.Dim();
-    ready_read_condition_.notify_one();
 }
 
 // bool RawAudioSource::AcceptWaveform(BaseFloat* data, int length) {
@@ -53,7 +52,7 @@ bool RawAudioSource::Read(Vector<BaseFloat>* feat) {
     std::unique_lock<std::mutex> lock(mutex_);
     while (chunk_size > data_length_) {
         // when audio is empty and no more data feed
-        // ready_read_condition will block in dead lock.
+        // ready_read_condition will block in dead lock. so replace with timeout_
         // ready_read_condition_.wait(lock);
         int32 elapsed = static_cast<int32>(timer.Elapsed() * 1000);
         if (elapsed > timeout_) {
@@ -82,4 +81,4 @@ bool RawAudioSource::Read(Vector<BaseFloat>* feat) {
     return true;
 }
 
-}  // namespace ppspeech
\ No newline at end of file
+}  // namespace ppspeech
diff --git a/speechx/speechx/frontend/raw_audio.h b/speechx/speechx/frontend/raw_audio.h
index 1893da25..c3ebe559 100644
--- a/speechx/speechx/frontend/raw_audio.h
+++ b/speechx/speechx/frontend/raw_audio.h
@@ -18,8 +18,6 @@
 #include "base/common.h"
 #include "frontend/feature_extractor_interface.h"
 
-#pragma once
-
 namespace ppspeech {
 
 class RawAudioSource : public FeatureExtractorInterface {
@@ -40,7 +38,6 @@ class RawAudioSource : public FeatureExtractorInterface {
     size_t data_length_;
     bool finished_;
     mutable std::mutex mutex_;
-    std::condition_variable ready_read_condition_;
     std::condition_variable ready_feed_condition_;
     kaldi::int32 timeout_;
 
@@ -74,4 +71,4 @@ class RawDataSource : public FeatureExtractorInterface {
     DISALLOW_COPY_AND_ASSIGN(RawDataSource);
 };
 
-}  // namespace ppspeech
\ No newline at end of file
+}  // namespace ppspeech