Add: retrieve thumbnail of audio

app/src/main/cpp/metadata/ffmpeg_media_retriever.c

@@ -487,7 +487,7 @@ void convert_image(State *state, AVCodecContext *pCodecCtx, AVFrame *pFrame, AVP
 	}
 }
 
-int get_embedded_picture(State **state_ptr, AVPacket *pkt) {
+int get_audio_thumbnail(State **state_ptr, AVPacket *pkt) {
 	int i = 0;
 	int got_packet = 0;
 	AVFrame *frame = NULL;

app/src/main/cpp/metadata/ffmpeg_media_retriever.h

@@ -54,6 +54,7 @@ int set_data_source_fd(State **ps, int fd, int64_t offset, int64_t length);
 const char* extract_metadata(State **ps, const char* key);
 int get_frame_at_time(State **ps, int64_t timeUs, int option, AVPacket *pkt);
 int get_scaled_frame_at_time(State **ps, int64_t timeUs, int option, AVPacket *pkt, int width, int height);
+int get_audio_thumbnail(State **state_ptr, AVPacket *pkt);
 int set_native_window(State **ps, ANativeWindow* native_window);
 void release(State **ps);
 

app/src/main/cpp/metadata/media_retriever.cpp

@@ -47,6 +47,12 @@ int MediaRetriever::getScaledFrameAtTime(int64_t timeUs, int option, AVPacket *p
 	return ::get_scaled_frame_at_time(&state, timeUs, option, pkt, width, height);
 }
 
+int MediaRetriever::getAudioThumbnail(AVPacket *pkt)
+{
+	Mutex::Autolock lock(mLock);
+	return ::get_audio_thumbnail(&state, pkt);
+}
+
 int MediaRetriever::setNativeWindow(ANativeWindow* native_window)
 {
 	Mutex::Autolock lock(mLock);

app/src/main/cpp/metadata/media_retriever.h

@@ -30,6 +30,7 @@ public:
     const char* extractMetadata(const char* key);
     int getFrameAtTime(int64_t timeUs, int option, AVPacket *pkt);
     int getScaledFrameAtTime(int64_t timeUs, int option, AVPacket *pkt, int width, int height);
+	int getAudioThumbnail(AVPacket *pkt);
     int setNativeWindow(ANativeWindow* native_window);
 
 private:

app/src/main/cpp/metadata/media_retriever_jni.cpp

@@ -260,6 +260,37 @@ RETRIEVER_FUNC(jbyteArray, native_1getScaleFrameAtTime, jlong timeUs, jint optio
     return array;
 }
 
+RETRIEVER_FUNC(jbyteArray, native_1getAudioThumbnail)
+{
+    MediaRetriever* retriever = getRetriever(env, thiz);
+    if (retriever == nullptr) {
+        jniThrowException(env, mIllegalStateException, mNoAvailableMsg);
+        return nullptr;
+    }
+
+    AVPacket packet;
+    av_init_packet(&packet);
+    jbyteArray array = nullptr;
+
+    if (retriever->getAudioThumbnail(&packet) == 0) {
+        int size = packet.size;
+        uint8_t* data = packet.data;
+        array = env->NewByteArray(size);
+        if (!array) {
+            LOGE(LOG_TAG, "getAudioThumbnail: OutOfMemoryError is thrown.");
+        } else {
+            jbyte* bytes = env->GetByteArrayElements(array, nullptr);
+            if (bytes != nullptr) {
+                memcpy(bytes, data, size);
+                env->ReleaseByteArrayElements(array, bytes, 0);
+            }
+        }
+    }
+
+    av_packet_unref(&packet);
+    return array;
+}
+
 RETRIEVER_FUNC(void, native_1release)
 {
     MediaRetriever* retriever = getRetriever(env, thiz);

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

@@ -185,6 +185,8 @@ class ProbeFormatActivity : BaseActivity() {
 
             // Retrieve frame with timeUs
             val bitmap = retriever.getFrameAtTime(5 * 1000000)
+            // Retrieve audio thumbnail, if it has embedded
+//            val bitmap = retriever.audioThumbnail
             if (bitmap != null) {
                 Log.e("FFmpegRetriever", "bitmap width=${bitmap.width}--height=${bitmap.height}")
                 mHandler.obtainMessage(MSG_FRAME, bitmap).sendToTarget()

app/src/main/java/com/frank/ffmpeg/metadata/FFmpegMediaRetriever.java

@@ -203,6 +203,15 @@ public class FFmpegMediaRetriever {
         return getScaledFrameAtTime(timeUs, OPTION_CLOSEST_SYNC, width, height);
     }
 
+    public Bitmap getAudioThumbnail() {
+        byte[] picture = native_getAudioThumbnail();
+        if (picture != null) {
+            return BitmapFactory.decodeByteArray(picture, 0, picture.length, null);
+        }
+
+        return null;
+    }
+
     public void release() {
         native_release();
     }
@@ -223,6 +232,8 @@ public class FFmpegMediaRetriever {
 
     private native byte[] native_getScaleFrameAtTime(long timeUs, int option, int width, int height);
 
+    private native byte[] native_getAudioThumbnail();
+
     private native void native_release();
 
     /**

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

@@ -13,9 +13,10 @@
             android:layout_height="wrap_content"
             android:layout_marginTop="50dp"
             android:text="@string/media_probe"
+            android:textSize="12sp"
             android:textColor="@color/colorPrimary"
             android:layout_alignParentStart="true"
-            android:layout_marginStart="20dp"/>
+            android:layout_marginStart="10dp"/>
 
         <Button
             android:id="@+id/btn_retrieve_format"
@@ -23,9 +24,10 @@
             android:layout_height="wrap_content"
             android:layout_marginTop="50dp"
             android:text="@string/media_retrieve"
+            android:textSize="12sp"
             android:textColor="@color/colorPrimary"
             android:layout_alignParentEnd="true"
-            android:layout_marginEnd="20dp"/>
+            android:layout_marginEnd="10dp"/>
 
         <TextView
             android:id="@+id/txt_probe_format"