add jni interface

app/CMakeLists.txt

@@ -38,6 +38,7 @@ add_library( # Sets the name of the library.
             src/main/cpp/visualizer/fixed_fft.cpp
             src/main/cpp/visualizer/block_queue.c
             src/main/cpp/visualizer/frank_visualizer.cpp
+            src/main/cpp/visualizer/frank_visualizer_jni.cpp
             src/main/cpp/visualizer/window.cpp
         )
 

app/src/main/cpp/visualizer/frank_visualizer.h

@@ -36,12 +36,13 @@ typedef struct
 
 class FrankVisualizer {
 
+private:
+    std::mutex mFftLock;
+
 public:
     FrankVisualizer();
     ~FrankVisualizer();
 
-    std::mutex mFftLock;
-
     filter_sys_t *fft_context = nullptr;
 
     void fft_run();

app/src/main/cpp/visualizer/frank_visualizer_jni.cpp

@@ -0,0 +1,80 @@
+//
+// Created by frank on 2021/8/28.
+//
+
+#include <jni.h>
+#include "frank_visualizer.h"
+
+#define VISUALIZER_FUNC(RETURN_TYPE, NAME, ...) \
+  extern "C" { \
+  JNIEXPORT RETURN_TYPE \
+    Java_com_frank_ffmpeg_effect_FrankVisualizer_ ## NAME \
+      (JNIEnv* env, jobject thiz, ##__VA_ARGS__);\
+  } \
+  JNIEXPORT RETURN_TYPE \
+    Java_com_frank_ffmpeg_effect_FrankVisualizer_ ## NAME \
+      (JNIEnv* env, jobject thiz, ##__VA_ARGS__)\
+
+struct fields_t {
+    jfieldID context;
+};
+
+static fields_t fields;
+static const char *className = "com/frank/ffmpeg/effect/FrankVisualizer";
+
+void setCustomVisualizer(JNIEnv *env, jobject thiz) {
+    auto *customVisualizer = new FrankVisualizer();
+    jclass clazz = env->FindClass(className);
+    if (!clazz) {
+        return;
+    }
+    fields.context = env->GetFieldID(clazz, "mNativeVisualizer", "J");
+    if (!fields.context) {
+        return;
+    }
+    env->SetLongField(thiz, fields.context, (jlong) customVisualizer);
+}
+
+FrankVisualizer *getCustomVisualizer(JNIEnv *env, jobject thiz) {
+    if (!fields.context) return nullptr;
+    return (FrankVisualizer *) env->GetLongField(thiz, fields.context);
+}
+
+void fft_callback(JNIEnv *jniEnv, int8_t * arg, int samples) {
+    jclass visual_class = jniEnv->FindClass(className);
+    jmethodID fft_method = jniEnv->GetStaticMethodID(visual_class, "onFftCallback", "([B)V");
+    jbyteArray dataArray = jniEnv->NewByteArray(samples);
+    jniEnv->SetByteArrayRegion(dataArray, 0, samples, arg);
+    jniEnv->CallStaticVoidMethod(visual_class, fft_method, dataArray);
+    jniEnv->DeleteLocalRef(dataArray);
+}
+
+VISUALIZER_FUNC(int, nativeInitVisualizer) {
+    setCustomVisualizer(env, thiz);
+    FrankVisualizer *mVisualizer = getCustomVisualizer(env, thiz);
+    if (!mVisualizer) return -2;
+    return mVisualizer->init_visualizer();
+}
+
+VISUALIZER_FUNC(int, nativeCaptureData, jobject buffer, jint size) {
+    if (!buffer) return -1;
+    FrankVisualizer *mVisualizer = getCustomVisualizer(env, thiz);
+    if (!mVisualizer || !mVisualizer->fft_context) return -2;
+    int nb_samples = size < MAX_FFT_SIZE ? size : MAX_FFT_SIZE;
+    if (nb_samples >= MIN_FFT_SIZE) {
+        mVisualizer->fft_context->nb_samples = nb_samples;
+        auto *direct_buffer = static_cast<uint8_t *>(env->GetDirectBufferAddress(buffer));
+        memcpy(mVisualizer->fft_context->data, direct_buffer, static_cast<size_t>(nb_samples));
+        mVisualizer->fft_run();
+        fft_callback(env, mVisualizer->fft_context->output, mVisualizer->fft_context->out_samples);
+    }
+    return 0;
+}
+
+VISUALIZER_FUNC(void, nativeReleaseVisualizer) {
+    FrankVisualizer *mVisualizer = getCustomVisualizer(env, thiz);
+    if (!mVisualizer) return;
+    mVisualizer->release_visualizer();
+    delete mVisualizer;
+    env->SetLongField(thiz, fields.context, 0);
+}

app/src/main/java/com/frank/ffmpeg/effect/FrankVisualizer.java

@@ -0,0 +1,53 @@
+package com.frank.ffmpeg.effect;
+
+import java.nio.ByteBuffer;
+
+/**
+ * @author frank
+ * @date 2021/10/1 11:25
+ * @desc custom audio visualizer
+ */
+public class FrankVisualizer {
+
+    private long mNativeVisualizer;
+
+    private static OnFftDataListener mOnFftDataListener;
+
+    public FrankVisualizer() {}
+
+    public void setOnFftDataListener(OnFftDataListener onFftDataListener) {
+        mOnFftDataListener = onFftDataListener;
+    }
+
+    public int initVisualizer() {
+        return nativeInitVisualizer();
+    }
+
+    public void captureData(ByteBuffer data, int size) {
+        if (data == null || size <= 0) {
+            nativeCaptureData(data, size);
+        }
+    }
+
+    public void releaseVisualizer() {
+        mOnFftDataListener = null;
+        nativeReleaseVisualizer();
+    }
+
+    public interface OnFftDataListener {
+        void onFftData(byte[] data);
+    }
+
+    public static void onFftCallback(byte[] data) {
+        if (mOnFftDataListener != null) {
+            mOnFftDataListener.onFftData(data);
+        }
+    }
+
+    private native int nativeInitVisualizer();
+
+    private native int nativeCaptureData(ByteBuffer buffer, int size);
+
+    private native void nativeReleaseVisualizer();
+
+}