add audio denoise effect

app/src/main/java/com/frank/ffmpeg/activity/AudioHandleActivity.kt

@@ -104,7 +104,8 @@ class AudioHandleActivity : BaseActivity() {
                 R.id.btn_pcm_concat,
                 R.id.btn_audio_speed,
                 R.id.btn_audio_echo,
-                R.id.btn_audio_tremolo
+                R.id.btn_audio_tremolo,
+                R.id.btn_audio_denoise
         )
     }
 
@@ -235,6 +236,11 @@ class AudioHandleActivity : BaseActivity() {
                 val tremoloPath = PATH + File.separator + "tremolo.mp3"
                 commandLine = FFmpegUtil.audioTremolo(srcFile, frequency, depth, tremoloPath)
             }
+            R.id.btn_audio_denoise
+            -> {
+                val noisePath = PATH + File.separator + "denoise.mp3"
+                commandLine = FFmpegUtil.audioDenoise(srcFile, noisePath)
+            }
             else -> {
             }
         }

app/src/main/java/com/frank/ffmpeg/util/FFmpegUtil.java

@@ -120,6 +120,22 @@ public class FFmpegUtil {
         return tremoloCmd.split(" ");
     }
 
+    /**
+     * Denoise audio samples with FFT
+     *
+     * @param inputPath  input file
+     * @param outputPath output file
+     * @return mix success or not
+     */
+    public static String[] audioDenoise(String inputPath, String outputPath) {
+        // nr: noise reduction in dB, [0.01 to 97], Default value is 12 dB
+        // nf: noise floor in dB, [-80 to -20],  Default value is -50 dB
+        // nt: noise type {w:white noise v:vinyl noise s:shellac noise}
+        String fftDenoiseCmd = "ffmpeg -i %s -af afftdn %s";
+        fftDenoiseCmd = String.format(Locale.getDefault(), fftDenoiseCmd, inputPath, outputPath);
+        return fftDenoiseCmd.split(" ");
+    }
+
     /**
      * mux audio and video together
      *

app/src/main/res/layout/activity_audio_handle.xml

@@ -90,6 +90,13 @@
             android:text="@string/audio_tremolo"
             android:layout_marginTop="10dp" />
 
+        <Button
+            android:id="@+id/btn_audio_denoise"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:text="@string/audio_denoise"
+            android:layout_marginTop="10dp" />
+
     </LinearLayout>
 
     <include

app/src/main/res/values-en/strings.xml

@@ -11,6 +11,7 @@
     <string name="audio_speed">Audio speed</string>
     <string name="audio_echo">Echo effect</string>
     <string name="audio_tremolo">Tremolo effect</string>
+    <string name="audio_denoise">Audio denoise</string>
     <string name="audio_effect">Audio effect</string>
     <string name="audio_equalizer">Audio equalizer:</string>
     <string name="audio_style">Audio style:</string>

app/src/main/res/values/strings.xml

@@ -3,7 +3,7 @@
     <string name="audio_transform">音频转码</string>
     <string name="audio_cut">音频剪切</string>
     <string name="audio_concat">音频合并</string>
-    <string name="audio_mix">音频混合</string>
+    <string name="audio_mix">音乐混音</string>
     <string name="audio_play">音频解码AudioTrack播放</string>
     <string name="audio_opensl">音频解码OpenSL播放</string>
     <string name="audio_encode">PCM编码</string>
@@ -11,6 +11,7 @@
     <string name="audio_speed">音频速度</string>
     <string name="audio_echo">空灵效果</string>
     <string name="audio_tremolo">惊悚效果</string>
+    <string name="audio_denoise">音频降噪</string>
     <string name="audio_effect">音乐均衡器</string>
     <string name="audio_equalizer">均衡器:</string>
     <string name="audio_style">风格:</string>