diff --git a/app/src/main/cpp/audio_player.cpp b/app/src/main/cpp/audio_player.cpp
index 7af1b48..74b67ff 100644
--- a/app/src/main/cpp/audio_player.cpp
+++ b/app/src/main/cpp/audio_player.cpp
@@ -285,11 +285,11 @@ AUDIO_PLAYER_FUNC(void, play, jstring input_jstr, jstring filter_jstr) {
 
     jmethodID fft_method = env->GetMethodID(player_class, "fftCallbackFromJNI", "([S)V");
 
-    filter_sys_t *fft_filter = static_cast<filter_sys_t *>(malloc(sizeof(filter_sys_t)));
+    auto *fft_filter = static_cast<filter_sys_t *>(malloc(sizeof(filter_sys_t)));
     init_visualizer(fft_filter);
-    auto *block = static_cast<block_t *>(malloc(sizeof(block_t)));
-    block->i_nb_samples = 0;
-    int16_t *output = static_cast<int16_t *>(malloc(FFT_BUFFER_SIZE * sizeof(int16_t)));
+    uint8_t *data = nullptr;
+    int nb_samples = 0;
+    auto *output = static_cast<int16_t *>(malloc(FFT_BUFFER_SIZE * sizeof(int16_t)));
 
     //read audio frame
     while (av_read_frame(pFormatCtx, packet) >= 0 && !filter_release) {
@@ -312,14 +312,13 @@ AUDIO_PLAYER_FUNC(void, play, jstring input_jstr, jstring filter_jstr) {
         }
         if (got_frame > 0) {
 
-            if (block->i_nb_samples == 0 && frame->nb_samples > 100) {
-                auto *data = static_cast<uint8_t *>(malloc(frame->nb_samples * sizeof(uint8_t)));
-                block->p_buffer = data;
-                block->i_nb_samples = static_cast<unsigned int>(frame->nb_samples);
+            if (frame->nb_samples > 256) {
+                nb_samples = frame->nb_samples;
+                data = static_cast<uint8_t *>(malloc(frame->nb_samples * sizeof(uint8_t)));
             }
-            if (block->i_nb_samples == frame->nb_samples) {
-                memcpy(block->p_buffer, frame->data[0], static_cast<size_t>(frame->nb_samples));
-                fft_once(fft_filter, block, output);
+            if (nb_samples == frame->nb_samples) {
+                memcpy(data, frame->data[0], static_cast<size_t>(frame->nb_samples));
+                fft_once(fft_filter, data, nb_samples, output);
                 fft_callback(env, thiz, fft_method, output);
             }
 
diff --git a/app/src/main/cpp/visualizer/execute_fft.c b/app/src/main/cpp/visualizer/execute_fft.c
index a96c8ca..4672aae 100644
--- a/app/src/main/cpp/visualizer/execute_fft.c
+++ b/app/src/main/cpp/visualizer/execute_fft.c
@@ -208,7 +208,7 @@ void release_visualizer(filter_sys_t *p_filter)
     free(p_sys);
 }
 
-void fft_once(void *p_data, block_t *block, int16_t *output)
+void fft_once(void *p_data, uint8_t *p_buffer, int nb_samples, int16_t *output)
 {
     filter_sys_t *p_sys = (filter_sys_t*)p_data;
 
@@ -219,31 +219,31 @@ void fft_once(void *p_data, block_t *block, int16_t *output)
     float p_output[FFT_BUFFER_SIZE];           /* Raw FFT Result  */
     int16_t p_buffer1[FFT_BUFFER_SIZE];        /* Buffer on which we perform
                                                   the FFT (first channel) */
-    float *p_buffl = (float*)block->p_buffer;  /* Original buffer */
+    float *p_buffl = (float*)p_buffer;  /* Original buffer */
 
     int16_t  *p_buffs;                         /* int16_t converted buffer */
     int16_t  *p_s16_buff;                      /* int16_t converted buffer */
 
-    if (!block->i_nb_samples) {
+    if (!nb_samples) {
         LOGE("no samples yet...");
         goto release;
     }
 
     /* Allocate the buffer only if the number of samples change */
-    if (block->i_nb_samples != p_sys->i_prev_nb_samples)
+    if (nb_samples != p_sys->i_prev_nb_samples)
     {
         free(p_sys->p_prev_s16_buff);
-        p_sys->p_prev_s16_buff = malloc(block->i_nb_samples *
+        p_sys->p_prev_s16_buff = malloc(nb_samples *
                                         p_sys->i_channels *
                                         sizeof(int16_t));
         if (!p_sys->p_prev_s16_buff)
             goto release;
-        p_sys->i_prev_nb_samples = block->i_nb_samples;
+        p_sys->i_prev_nb_samples = nb_samples;
     }
     p_buffs = p_s16_buff = p_sys->p_prev_s16_buff;
 
     /* Convert the buffer to int16_t */
-    for (i = block->i_nb_samples * p_sys->i_channels; i--;)
+    for (i = nb_samples * p_sys->i_channels; i--;)
     {
         union {float f; int32_t i;} u;
 
@@ -275,14 +275,14 @@ void fft_once(void *p_data, block_t *block, int16_t *output)
         p_buffer1[i] = *p_buffs;
 
         p_buffs += p_sys->i_channels;
-        if (p_buffs >= &p_s16_buff[block->i_nb_samples * p_sys->i_channels])
+        if (p_buffs >= &p_s16_buff[nb_samples * p_sys->i_channels])
             p_buffs = p_s16_buff;
     }
     window_scale_in_place (p_buffer1, &wind_ctx);
     fft_perform (p_buffer1, p_output, p_state);
 
-    for (i = 0; i< FFT_BUFFER_SIZE; ++i)
-        output[i] = p_output[i] *  (2 ^ 16)
+    for (i = 0; i < FFT_BUFFER_SIZE; ++i)
+        output[i] = p_output[i] * (2 ^ 16)
                     / ((FFT_BUFFER_SIZE / 2 * 32768) ^ 2);
 
     LOGE("out[100]=%d,out[101]=%d,out[102]=%d", output[100], output[101], output[102]);
diff --git a/app/src/main/cpp/visualizer/execute_fft.h b/app/src/main/cpp/visualizer/execute_fft.h
index bc63825..078f13c 100644
--- a/app/src/main/cpp/visualizer/execute_fft.h
+++ b/app/src/main/cpp/visualizer/execute_fft.h
@@ -45,7 +45,7 @@ block_t *filter_audio(filter_sys_t *p_sys, void *p_in_buf);
 
 void close_visualizer(filter_sys_t *p_filter);
 
-void fft_once(void *p_data, block_t *block, int16_t *output);
+void fft_once(void *p_data, uint8_t *p_buffer, int nb_samples, int16_t *output);
 
 int init_visualizer(filter_sys_t *p_sys);