GStreamer SDKのチュートリアルが複雑すぎたので、なるべく簡単に音声を再生するサンプルコードを書いてみた。参考サイトはこちら。 http://docs.gstreamer.com/display/GstSDK/Android+tutorial+2%3A+A+running+pipeline

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <Button
        android:id="@+id/play"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Play" />

    <Button
        android:id="@+id/stop"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Stop" />

</LinearLayout>

Android.mk

LOCAL_PATH := $(call my-dir)
 
include $(CLEAR_VARS)
 
LOCAL_MODULE    := NativeApplication
LOCAL_SRC_FILES := NativeApplication.c
LOCAL_SHARED_LIBRARIES := gstreamer_android
LOCAL_LDLIBS := -landroid
 
include $(BUILD_SHARED_LIBRARY)
 
GSTREAMER_SDK_ROOT        := $(GSTREAMER_SDK_ROOT_ANDROID)
GSTREAMER_NDK_BUILD_PATH  := $(GSTREAMER_SDK_ROOT)/share/gst-android/ndk-build/
include $(GSTREAMER_NDK_BUILD_PATH)/plugins.mk
GSTREAMER_PLUGINS         := $(GSTREAMER_PLUGINS_CORE) $(GSTREAMER_PLUGINS_SYS)
include $(GSTREAMER_NDK_BUILD_PATH)/gstreamer.mk

#G_IO_MODULES              := gnutls
#GSTREAMER_EXTRA_DEPS      := gstreamer-interfaces-0.10 gstreamer-video-0.10
# 
#include $(GSTREAMER_NDK_BUILD_PATH)/gstreamer.mk 

MainActivity.java

package com.example.test;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Toast;

import com.gstreamer.GStreamer;

public class MainActivity extends Activity {
	private native void nativeInit();

	private native void nativeFinalize();

	private native void nativePlay();

	private native void nativeStop();

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);

		try {
			GStreamer.init(this);
		} catch (Exception e) {
			Toast.makeText(this, e.getMessage(), Toast.LENGTH_LONG).show();
			finish();
		}

		setContentView(R.layout.activity_main);

		findViewById(R.id.play).setOnClickListener(new OnClickListener() {

			@Override
			public void onClick(View v) {
				nativePlay();
			}
		});

		findViewById(R.id.stop).setOnClickListener(new OnClickListener() {
			@Override
			public void onClick(View v) {
				nativeStop();
			}
		});

		nativeInit();
	}

	@Override
	protected void onDestroy() {
		nativeFinalize();
		super.onDestroy();
	}

	static {
		System.loadLibrary("gstreamer_android");
		System.loadLibrary("NativeApplication");
	}
}

NativeApplication.c

#include <string.h>
#include <jni.h>
#include <android/log.h>
#include <gst/gst.h>

static GstElement *pipeline;

void Java_com_example_test_MainActivity_nativeInit(JNIEnv* env, jobject thiz) {
	GError *error = NULL;
	pipeline = gst_parse_launch(
			"audiotestsrc ! audioconvert ! audioresample ! autoaudiosink",
			&error);

	if (error) {
		g_clear_error(&error);
		return;
	}
}

void Java_com_example_test_MainActivity_nativeFinalize(JNIEnv* env,
		jobject thiz) {
	gst_element_set_state(pipeline, GST_STATE_NULL);
	gst_object_unref(pipeline);
}

void Java_com_example_test_MainActivity_nativePlay(JNIEnv* env, jobject thiz) {
	gst_element_set_state(pipeline, GST_STATE_PLAYING);
}

void Java_com_example_test_MainActivity_nativeStop(JNIEnv* env, jobject thiz) {
	gst_element_set_state(pipeline, GST_STATE_PAUSED);
}