diff --git a/speechx/examples/README.md b/speechx/examples/README.md
index 50f5f902..18b37281 100644
--- a/speechx/examples/README.md
+++ b/speechx/examples/README.md
@@ -1,7 +1,7 @@
 # Examples for SpeechX
 
-* ds2_ol - ds2 streaming test under `aishell-1` test dataset.
-   The entrypoint is `ds2_ol/aishell/run.sh`
+* ds2_ol - ds2 streaming test under `aishell-1` test dataset.  
+The entrypoint is `ds2_ol/aishell/run.sh`
 
 
 ## How to run  
diff --git a/speechx/examples/ds2_ol/README.md b/speechx/examples/ds2_ol/README.md
index 18f248a1..ed88ef6b 100644
--- a/speechx/examples/ds2_ol/README.md
+++ b/speechx/examples/ds2_ol/README.md
@@ -1,12 +1,12 @@
-# Deepspeech2 Streaming
+# Deepspeech2 Streaming ASR
 
-Please go to `aishell` to test it.
-
-* aishell
-Deepspeech2 Streaming Decoding under aishell dataset.
 * websocket
 Streaming ASR with websocket.
 
+* aishell
+Streaming Decoding under aishell dataset, for local WER test and so on.
+
+## More
 The below is for developing and offline testing:
 * nnet
 * feat
diff --git a/speechx/examples/ds2_ol/aishell/run.sh b/speechx/examples/ds2_ol/aishell/run.sh
index 06f27427..049c9bf9 100755
--- a/speechx/examples/ds2_ol/aishell/run.sh
+++ b/speechx/examples/ds2_ol/aishell/run.sh
@@ -112,8 +112,8 @@ if [ ${stage} -le 3 ] && [ ${stop_stage} -ge 3 ]; then
     utils/compute-wer.py --char=1 --v=1 $text $exp/${label_file}_lm > $exp/${wer}.lm
 fi
 
+wfst=$data/wfst/
 if [ ${stage} -le 4 ] && [ ${stop_stage} -ge 4 ]; then
-    wfst=$data/wfst/
     mkdir -p $wfst
     if [ ! -f $wfst/aishell_graph.zip ]; then
         pushd $wfst
@@ -122,18 +122,18 @@ if [ ${stage} -le 4 ] && [ ${stop_stage} -ge 4 ]; then
         mv aishell_graph/* $wfst
         popd
     fi
+fi
 
-    graph_dir=$wfst/
-
+if [ ${stage} -le 4 ] && [ ${stop_stage} -ge 4 ]; then
     #  TLG decoder
     utils/run.pl JOB=1:$nj $data/split${nj}/JOB/recog.wfst.log \
     wfst-decoder-ol \
         --feature_rspecifier=scp:$data/split${nj}/JOB/feat.scp \
         --model_path=$model_dir/avg_1.jit.pdmodel \
         --param_path=$model_dir/avg_1.jit.pdiparams \
-        --word_symbol_table=$graph_dir/words.txt \
+        --word_symbol_table=$wfst/words.txt \
         --model_output_names=softmax_0.tmp_0,tmp_5,concat_0.tmp_0,concat_1.tmp_0 \
-        --graph_path=$graph_dir/TLG.fst --max_active=7500 \
+        --graph_path=$wfst/TLG.fst --max_active=7500 \
         --acoustic_scale=1.2 \
         --result_wspecifier=ark,t:$data/split${nj}/JOB/result_tlg
 
@@ -142,40 +142,21 @@ if [ ${stage} -le 4 ] && [ ${stop_stage} -ge 4 ]; then
 fi
 
 if [ ${stage} -le 5 ] && [ ${stop_stage} -ge 5 ]; then
-
-    cmvn=$data/cmvn.ark
-    if [ ! -f $data/split${nj}/1/${aishell_wav_scp} ]; then
-        cmvn-json2kaldi --json_file=$ckpt_dir/data/mean_std.json --cmvn_write_path=$cmvn
-        ./local/split_data.sh $data ${data}/${aishell_wav_scp} $aishell_wav_scp $nj
-    fi
-
-    wfst=$data/wfst/
-    mkdir -p $wfst
-    if [ ! -f $wfst/aishell_graph.zip ]; then
-        pushd $wfst
-        wget -c https://paddlespeech.bj.bcebos.com/s2t/paddle_asr_online/aishell_graph.zip
-        unzip aishell_graph.zip
-        popd
-    fi
-
-    graph_dir=$wfst/aishell_graph
-
     #  TLG decoder
     utils/run.pl JOB=1:$nj $data/split${nj}/JOB/recognizer.log \
     recognizer_test_main \
         --wav_rspecifier=scp:$data/split${nj}/JOB/${aishell_wav_scp} \
         --cmvn_file=$cmvn \
         --model_path=$model_dir/avg_1.jit.pdmodel \
-        --convert2PCM32=true \
+        --to_float32=true \
         --streaming_chunk=30 \
-        --params_path=$model_dir/avg_1.jit.pdiparams \
-        --word_symbol_table=$graph_dir/words.txt \
+        --param_path=$model_dir/avg_1.jit.pdiparams \
+        --word_symbol_table=$wfst/words.txt \
         --model_output_names=softmax_0.tmp_0,tmp_5,concat_0.tmp_0,concat_1.tmp_0 \
-        --graph_path=$graph_dir/TLG.fst --max_active=7500 \
+        --graph_path=$wfst/TLG.fst --max_active=7500 \
         --acoustic_scale=1.2 \
         --result_wspecifier=ark,t:$data/split${nj}/JOB/result_recognizer
 
     cat $data/split${nj}/*/result_recognizer > $exp/${label_file}_recognizer
     utils/compute-wer.py --char=1 --v=1 $text $exp/${label_file}_recognizer > $exp/${wer}.recognizer
-fi
-
+fi
\ No newline at end of file
diff --git a/speechx/examples/ds2_ol/feat/linear-spectrogram-wo-db-norm-ol.cc b/speechx/examples/ds2_ol/feat/linear-spectrogram-wo-db-norm-ol.cc
index 6f532af4..f8f62f84 100644
--- a/speechx/examples/ds2_ol/feat/linear-spectrogram-wo-db-norm-ol.cc
+++ b/speechx/examples/ds2_ol/feat/linear-spectrogram-wo-db-norm-ol.cc
@@ -115,7 +115,7 @@ int main(int argc, char* argv[]) {
                 flag = feature_cache.Read(&features);
                 feats.push_back(features);
                 feature_rows += features.Dim() / feature_cache.Dim();
-            } while(flag == true && features.Dim() != 0);
+            } while (flag == true && features.Dim() != 0);
             sample_offset += cur_chunk_size;
         }
 
diff --git a/speechx/examples/ds2_ol/websocket/websocket_client.sh b/speechx/examples/ds2_ol/websocket/websocket_client.sh
index 3c6b4e91..2a52d2a3 100755
--- a/speechx/examples/ds2_ol/websocket/websocket_client.sh
+++ b/speechx/examples/ds2_ol/websocket/websocket_client.sh
@@ -14,9 +14,7 @@ fi
 # input
 mkdir -p data
 data=$PWD/data
-ckpt_dir=$data/model
-model_dir=$ckpt_dir/exp/deepspeech2_online/checkpoints/
-vocb_dir=$ckpt_dir/data/lang_char
+
 # output
 aishell_wav_scp=aishell_test.scp
 if [ ! -d $data/test ]; then
@@ -34,4 +32,4 @@ export GLOG_logtostderr=1
 
 # websocket client
 websocket_client_main \
-    --wav_rspecifier=scp:$data/$aishell_wav_scp --streaming_chunk=0.36
+    --wav_rspecifier=scp:$data/$aishell_wav_scp --streaming_chunk=0.36
\ No newline at end of file
diff --git a/speechx/examples/ds2_ol/websocket/websocket_server.sh b/speechx/examples/ds2_ol/websocket/websocket_server.sh
index 0e9e796c..0e389f89 100755
--- a/speechx/examples/ds2_ol/websocket/websocket_server.sh
+++ b/speechx/examples/ds2_ol/websocket/websocket_server.sh
@@ -19,12 +19,26 @@ ckpt_dir=$data/model
 model_dir=$ckpt_dir/exp/deepspeech2_online/checkpoints/
 vocb_dir=$ckpt_dir/data/lang_char/
 
+# output
+aishell_wav_scp=aishell_test.scp
+if [ ! -d $data/test ]; then
+    pushd $data
+    wget -c https://paddlespeech.bj.bcebos.com/s2t/paddle_asr_online/aishell_test.zip
+    unzip  aishell_test.zip
+    popd
+
+    realpath $data/test/*/*.wav > $data/wavlist
+    awk -F '/' '{ print $(NF) }' $data/wavlist | awk -F '.' '{ print $1 }' > $data/utt_id
+    paste $data/utt_id $data/wavlist > $data/$aishell_wav_scp
+fi
+
+
 if [ ! -f $ckpt_dir/data/mean_std.json ]; then
-        mkdir -p $ckpt_dir
-        pushd $ckpt_dir
-        wget -c https://paddlespeech.bj.bcebos.com/s2t/aishell/asr0/asr0_deepspeech2_online_aishell_ckpt_0.2.0.model.tar.gz
-        tar xzfv asr0_deepspeech2_online_aishell_ckpt_0.2.0.model.tar.gz 
-        popd
+    mkdir -p $ckpt_dir
+    pushd $ckpt_dir
+    wget -c https://paddlespeech.bj.bcebos.com/s2t/aishell/asr0/asr0_deepspeech2_online_aishell_ckpt_0.2.0.model.tar.gz
+    tar xzfv asr0_deepspeech2_online_aishell_ckpt_0.2.0.model.tar.gz 
+    popd
 fi
 
 export GLOG_logtostderr=1
@@ -49,9 +63,9 @@ websocket_server_main \
     --cmvn_file=$cmvn \
     --model_path=$model_dir/avg_1.jit.pdmodel \
     --streaming_chunk=0.1 \
-    --convert2PCM32=true \
+    --to_float32=true \
     --param_path=$model_dir/avg_1.jit.pdiparams \
-    --word_symbol_table=$data/wfst/words.txt \
+    --word_symbol_table=$wfst/words.txt \
     --model_output_names=softmax_0.tmp_0,tmp_5,concat_0.tmp_0,concat_1.tmp_0 \
-    --graph_path=$data/wfst/TLG.fst --max_active=7500 \
+    --graph_path=$wfst/TLG.fst --max_active=7500 \
     --acoustic_scale=1.2 
diff --git a/speechx/speechx/decoder/param.h b/speechx/speechx/decoder/param.h
index aff8d39a..f6bd77ca 100644
--- a/speechx/speechx/decoder/param.h
+++ b/speechx/speechx/decoder/param.h
@@ -21,7 +21,7 @@
 
 DEFINE_string(cmvn_file, "", "read cmvn");
 DEFINE_double(streaming_chunk, 0.1, "streaming feature chunk size");
-DEFINE_bool(convert2PCM32, true, "audio convert to pcm32");
+DEFINE_bool(to_float32, true, "audio convert to pcm32");
 DEFINE_string(model_path, "avg_1.jit.pdmodel", "paddle nnet model");
 DEFINE_string(param_path, "avg_1.jit.pdiparams", "paddle nnet model param");
 DEFINE_string(word_symbol_table, "words.txt", "word symbol table");
@@ -52,7 +52,7 @@ FeaturePipelineOptions InitFeaturePipelineOptions() {
     FeaturePipelineOptions opts;
     opts.cmvn_file = FLAGS_cmvn_file;
     opts.linear_spectrogram_opts.streaming_chunk = FLAGS_streaming_chunk;
-    opts.convert2PCM32 = FLAGS_convert2PCM32;
+    opts.to_float32 = FLAGS_to_float32;
     kaldi::FrameExtractionOptions frame_opts;
     frame_opts.frame_length_ms = 20;
     frame_opts.frame_shift_ms = 10;
diff --git a/speechx/speechx/frontend/audio/audio_cache.cc b/speechx/speechx/frontend/audio/audio_cache.cc
index e8af6668..b7a15acd 100644
--- a/speechx/speechx/frontend/audio/audio_cache.cc
+++ b/speechx/speechx/frontend/audio/audio_cache.cc
@@ -21,17 +21,18 @@ using kaldi::BaseFloat;
 using kaldi::VectorBase;
 using kaldi::Vector;
 
-AudioCache::AudioCache(int buffer_size, bool convert2PCM32)
+AudioCache::AudioCache(int buffer_size, bool to_float32)
     : finished_(false),
-      capacity_(buffer_size),
+      capacity_(buffer_size),  // unit: sample
       size_(0),
       offset_(0),
-      timeout_(1),
-      convert2PCM32_(convert2PCM32) {
+      timeout_(1),  // ms
+      to_float32_(to_float32) {
     ring_buffer_.resize(capacity_);
 }
 
 BaseFloat AudioCache::Convert2PCM32(BaseFloat val) {
+    // sample type int16, int16->float32
     return val * (1. / std::pow(2.0, 15));
 }
 
@@ -43,8 +44,7 @@ void AudioCache::Accept(const VectorBase<BaseFloat>& waves) {
     for (size_t idx = 0; idx < waves.Dim(); ++idx) {
         int32 buffer_idx = (idx + offset_ + size_) % ring_buffer_.size();
         ring_buffer_[buffer_idx] = waves(idx);
-        if (convert2PCM32_)
-            ring_buffer_[buffer_idx] = Convert2PCM32(waves(idx));
+        if (to_float32_) ring_buffer_[buffer_idx] = Convert2PCM32(waves(idx));
     }
     size_ += waves.Dim();
 }
diff --git a/speechx/speechx/frontend/audio/audio_cache.h b/speechx/speechx/frontend/audio/audio_cache.h
index a681ef09..371b2cc2 100644
--- a/speechx/speechx/frontend/audio/audio_cache.h
+++ b/speechx/speechx/frontend/audio/audio_cache.h
@@ -24,7 +24,7 @@ namespace ppspeech {
 class AudioCache : public FrontendInterface {
   public:
     explicit AudioCache(int buffer_size = 1000 * kint16max,
-                        bool convert2PCM32 = true);
+                        bool to_float32 = true);
 
     virtual void Accept(const kaldi::VectorBase<BaseFloat>& waves);
 
@@ -50,14 +50,15 @@ class AudioCache : public FrontendInterface {
     kaldi::BaseFloat Convert2PCM32(kaldi::BaseFloat val);
 
     std::vector<kaldi::BaseFloat> ring_buffer_;
-    size_t offset_;    // offset in ring_buffer_
-    size_t size_;      // samples in ring_buffer_ now
-    size_t capacity_;  // capacity of ring_buffer_
+    size_t offset_;    // offset in ring_buffer_, begin of data
+    size_t size_;      // samples in ring_buffer_, size of valid data
+    size_t capacity_;  // capacity of ring_buffer_, full size of data buffer,
+                       // unit: sample
     bool finished_;    // reach audio end
     std::mutex mutex_;
     std::condition_variable ready_feed_condition_;
     kaldi::int32 timeout_;  // millisecond
-    bool convert2PCM32_;
+    bool to_float32_;
 
     DISALLOW_COPY_AND_ASSIGN(AudioCache);
 };
diff --git a/speechx/speechx/frontend/audio/cmvn.cc b/speechx/speechx/frontend/audio/cmvn.cc
index c7e446c9..1ea83aba 100644
--- a/speechx/speechx/frontend/audio/cmvn.cc
+++ b/speechx/speechx/frontend/audio/cmvn.cc
@@ -37,14 +37,17 @@ CMVN::CMVN(std::string cmvn_file, unique_ptr<FrontendInterface> base_extractor)
 }
 
 void CMVN::Accept(const kaldi::VectorBase<kaldi::BaseFloat>& inputs) {
+    // feed waves/feats to compute feature
     base_extractor_->Accept(inputs);
     return;
 }
 
 bool CMVN::Read(kaldi::Vector<BaseFloat>* feats) {
+    // compute feature
     if (base_extractor_->Read(feats) == false || feats->Dim() == 0) {
         return false;
     }
+    // appply cmvn
     Compute(feats);
     return true;
 }
diff --git a/speechx/speechx/frontend/audio/data_cache.h b/speechx/speechx/frontend/audio/data_cache.h
index a812278c..852385e9 100644
--- a/speechx/speechx/frontend/audio/data_cache.h
+++ b/speechx/speechx/frontend/audio/data_cache.h
@@ -27,6 +27,7 @@ class DataCache : public FrontendInterface {
   public:
     explicit DataCache() { finished_ = false; }
 
+    // accept waves/feats
     virtual void Accept(const kaldi::VectorBase<kaldi::BaseFloat>& inputs) {
         data_ = inputs;
     }
diff --git a/speechx/speechx/frontend/audio/fbank.h b/speechx/speechx/frontend/audio/fbank.h
index 68267b3d..96a97dfd 100644
--- a/speechx/speechx/frontend/audio/fbank.h
+++ b/speechx/speechx/frontend/audio/fbank.h
@@ -15,23 +15,56 @@
 // wrap the fbank feat of kaldi, todo (SmileGoat)
 
 #include "kaldi/feat/feature-mfcc.h"
-
 #incldue "kaldi/matrix/kaldi-vector.h"
 
 namespace ppspeech {
 
-class FbankExtractor : FrontendInterface {
+struct FbankOptions {
+    kaldi::FrameExtractionOptions frame_opts;
+    kaldi::BaseFloat streaming_chunk;  // second
+
+    LinearSpectrogramOptions() : streaming_chunk(0.1), frame_opts() {}
+
+    void Register(kaldi::OptionsItf* opts) {
+        opts->Register("streaming-chunk",
+                       &streaming_chunk,
+                       "streaming chunk size, default: 0.1 sec");
+        frame_opts.Register(opts);
+    }
+};
+
+
+class Fbank : FrontendInterface {
   public:
-    explicit FbankExtractor(const FbankOptions& opts,
-                            share_ptr<FrontendInterface> pre_extractor);
-    virtual void AcceptWaveform(
-        const kaldi::Vector<kaldi::BaseFloat>& input) = 0;
-    virtual void Read(kaldi::Vector<kaldi::BaseFloat>* feat) = 0;
-    virtual size_t Dim() const = 0;
+    explicit Fbank(const FbankOptions& opts,
+                   unique_ptr<FrontendInterface> base_extractor);
+    virtual void Accept(const kaldi::VectorBase<kaldi::BaseFloat>& inputs);
+    virtual bool Read(kaldi::Vector<kaldi::BaseFloat>* feats);
+
+    // the dim_ is the dim of single frame feature
+    virtual size_t Dim() const { return dim_; }
+
+    virtual void SetFinished() { base_extractor_->SetFinished(); }
+
+    virtual bool IsFinished() const { return base_extractor_->IsFinished(); }
+
+    virtual void Reset() {
+        base_extractor_->Reset();
+        remained_wav_.Resize(0);
+    }
 
   private:
-    bool Compute(const kaldi::Vector<kaldi::BaseFloat>& wave,
-                 kaldi::Vector<kaldi::BaseFloat>* feat) const;
+    bool Compute(const kaldi::Vector<kaldi::BaseFloat>& waves,
+                 kaldi::Vector<kaldi::BaseFloat>* feats);
+
+    // kaldi::FeatureWindowFunction feature_window_funtion_;
+    // kaldi::BaseFloat hanning_window_energy_;
+    size_t dim_;
+    FbankOptions opts_;
+    std::unique_ptr<FrontendInterface> base_extractor_;
+    kaldi::Vector<kaldi::BaseFloat> remained_wav_;
+    int chunk_sample_size_;
+    DISALLOW_COPY_AND_ASSIGN(Fbank);
 };
 
 }  // namespace ppspeech
\ No newline at end of file
diff --git a/speechx/speechx/frontend/audio/feature_cache.cc b/speechx/speechx/frontend/audio/feature_cache.cc
index b5768460..e1e1043b 100644
--- a/speechx/speechx/frontend/audio/feature_cache.cc
+++ b/speechx/speechx/frontend/audio/feature_cache.cc
@@ -28,11 +28,13 @@ FeatureCache::FeatureCache(FeatureCacheOptions opts,
     max_size_ = opts.max_size;
     frame_chunk_stride_ = opts.frame_chunk_stride;
     frame_chunk_size_ = opts.frame_chunk_size;
+    timeout_ = opts.timeout;  // ms
     base_extractor_ = std::move(base_extractor);
     dim_ = base_extractor_->Dim();
 }
 
 void FeatureCache::Accept(const kaldi::VectorBase<kaldi::BaseFloat>& inputs) {
+    // read inputs
     base_extractor_->Accept(inputs);
     // feed current data
     bool result = false;
@@ -49,9 +51,8 @@ bool FeatureCache::Read(kaldi::Vector<kaldi::BaseFloat>* feats) {
     while (cache_.empty() && base_extractor_->IsFinished() == false) {
         // todo refactor: wait
         // ready_read_condition_.wait(lock);
-        int32 elapsed = static_cast<int32>(timer.Elapsed() * 1000);
-        // todo replace 1 with timeout_, 1 ms
-        if (elapsed > 1) {
+        int32 elapsed = static_cast<int32>(timer.Elapsed() * 1000);  // ms
+        if (elapsed > timeout_) {
             return false;
         }
         usleep(100);  // sleep 0.1 ms
@@ -70,6 +71,8 @@ bool FeatureCache::Compute() {
     Vector<BaseFloat> feature;
     bool result = base_extractor_->Read(&feature);
     if (result == false || feature.Dim() == 0) return false;
+
+    // join with remained
     int32 joint_len = feature.Dim() + remained_feature_.Dim();
     int32 num_chunk =
         ((joint_len / dim_) - frame_chunk_size_) / frame_chunk_stride_ + 1;
@@ -82,6 +85,7 @@ bool FeatureCache::Compute() {
 
     for (int chunk_idx = 0; chunk_idx < num_chunk; ++chunk_idx) {
         int32 start = chunk_idx * frame_chunk_stride_ * dim_;
+
         Vector<BaseFloat> feature_chunk(frame_chunk_size_ * dim_);
         SubVector<BaseFloat> tmp(joint_feature.Data() + start,
                                  frame_chunk_size_ * dim_);
@@ -89,6 +93,7 @@ bool FeatureCache::Compute() {
 
         std::unique_lock<std::mutex> lock(mutex_);
         while (cache_.size() >= max_size_) {
+            // cache full, wait
             ready_feed_condition_.wait(lock);
         }
 
diff --git a/speechx/speechx/frontend/audio/feature_cache.h b/speechx/speechx/frontend/audio/feature_cache.h
index 607f72c0..0dc704bb 100644
--- a/speechx/speechx/frontend/audio/feature_cache.h
+++ b/speechx/speechx/frontend/audio/feature_cache.h
@@ -23,8 +23,12 @@ struct FeatureCacheOptions {
     int32 max_size;
     int32 frame_chunk_size;
     int32 frame_chunk_stride;
+    int32 timeout;  // ms
     FeatureCacheOptions()
-        : max_size(kint16max), frame_chunk_size(1), frame_chunk_stride(1) {}
+        : max_size(kint16max),
+          frame_chunk_size(1),
+          frame_chunk_stride(1),
+          timeout(1) {}
 };
 
 class FeatureCache : public FrontendInterface {
@@ -64,14 +68,15 @@ class FeatureCache : public FrontendInterface {
     bool Compute();
 
     int32 dim_;
-    size_t max_size_;
-    int32 frame_chunk_size_;
-    int32 frame_chunk_stride_;
+    size_t max_size_;           // cache capacity
+    int32 frame_chunk_size_;    // window
+    int32 frame_chunk_stride_;  // stride
+    std::unique_ptr<FrontendInterface> base_extractor_;
 
+    kaldi::int32 timeout_;  // ms
     kaldi::Vector<kaldi::BaseFloat> remained_feature_;
-    std::unique_ptr<FrontendInterface> base_extractor_;
+    std::queue<kaldi::Vector<BaseFloat>> cache_;  // feature cache
     std::mutex mutex_;
-    std::queue<kaldi::Vector<BaseFloat>> cache_;
     std::condition_variable ready_feed_condition_;
     std::condition_variable ready_read_condition_;
 
diff --git a/speechx/speechx/frontend/audio/feature_pipeline.cc b/speechx/speechx/frontend/audio/feature_pipeline.cc
index 86eca2e0..5914fedb 100644
--- a/speechx/speechx/frontend/audio/feature_pipeline.cc
+++ b/speechx/speechx/frontend/audio/feature_pipeline.cc
@@ -20,7 +20,7 @@ using std::unique_ptr;
 
 FeaturePipeline::FeaturePipeline(const FeaturePipelineOptions& opts) {
     unique_ptr<FrontendInterface> data_source(
-        new ppspeech::AudioCache(1000 * kint16max, opts.convert2PCM32));
+        new ppspeech::AudioCache(1000 * kint16max, opts.to_float32));
 
     unique_ptr<FrontendInterface> linear_spectrogram(
         new ppspeech::LinearSpectrogram(opts.linear_spectrogram_opts,
diff --git a/speechx/speechx/frontend/audio/feature_pipeline.h b/speechx/speechx/frontend/audio/feature_pipeline.h
index 7bd6c84f..580c02fa 100644
--- a/speechx/speechx/frontend/audio/feature_pipeline.h
+++ b/speechx/speechx/frontend/audio/feature_pipeline.h
@@ -27,12 +27,12 @@ namespace ppspeech {
 
 struct FeaturePipelineOptions {
     std::string cmvn_file;
-    bool convert2PCM32;
+    bool to_float32;
     LinearSpectrogramOptions linear_spectrogram_opts;
     FeatureCacheOptions feature_cache_opts;
     FeaturePipelineOptions()
         : cmvn_file(""),
-          convert2PCM32(false),
+          to_float32(false),
           linear_spectrogram_opts(),
           feature_cache_opts() {}
 };