Update

subprojects/gst-docs/examples/tutorials/android/android-tutorial-4/.gitignore

@@ -0,0 +1,4 @@
+.externalNativeBuild/
+assets/
+gst-build-*/
+src/org/

subprojects/gst-docs/examples/tutorials/android/android-tutorial-4/AndroidManifest.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+      package="org.freedesktop.gstreamer.tutorials.tutorial_4"
+      android:versionCode="1"
+      android:versionName="1.0">
+
+    <uses-permission android:name="android.permission.INTERNET"/>
+    <uses-feature android:glEsVersion="0x00020000"/>
+    <application android:label="@string/app_name"
+                 android:icon="@drawable/gstreamer_logo_4">
+        <activity android:name=".Tutorial4"
+                  android:label="@string/app_name"
+                  android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+</manifest>

subprojects/gst-docs/examples/tutorials/android/android-tutorial-4/build.gradle

@@ -0,0 +1,72 @@
+apply plugin: 'com.android.application'
+
+android {
+    compileSdkVersion 32
+
+    defaultConfig {
+        applicationId "org.freedesktop.gstreamer.tutorials.tutorial_4"
+        minSdkVersion 15
+        targetSdkVersion 32
+        versionCode 1
+        versionName "1.0"
+
+
+        externalNativeBuild {
+            ndkBuild {
+                def gstRoot
+
+                if (project.hasProperty('gstAndroidRoot'))
+                    gstRoot = project.gstAndroidRoot
+                else
+                    gstRoot = System.env.GSTREAMER_ROOT_ANDROID
+
+                if (gstRoot == null)
+                    throw new GradleException('GSTREAMER_ROOT_ANDROID must be set, or "gstAndroidRoot" must be defined in your gradle.properties in the top level directory of the unpacked universal GStreamer Android binaries')
+
+                arguments "NDK_APPLICATION_MK=jni/Application.mk", "GSTREAMER_JAVA_SRC_DIR=src", "GSTREAMER_ROOT_ANDROID=$gstRoot", "GSTREAMER_ASSETS_DIR=src/assets"
+
+                targets "tutorial-4"
+
+                // All archs except MIPS and MIPS64 are supported
+                abiFilters  'armeabi-v7a', 'arm64-v8a', 'x86', 'x86_64'
+            }
+        }
+    }
+
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
+            sourceSets {
+                main {
+                    manifest.srcFile 'AndroidManifest.xml'
+                    java.srcDirs = ['src']
+                    resources.srcDirs = ['src']
+                    aidl.srcDirs = ['src']
+                    renderscript.srcDirs = ['src']
+                    res.srcDirs = ['res']
+                    assets.srcDirs = ['assets']
+                }
+            }
+        }
+    }
+
+    externalNativeBuild {
+        ndkBuild {
+            path 'jni/Android.mk'
+        }
+    }
+}
+
+afterEvaluate {
+    if (project.hasProperty('compileDebugJavaWithJavac'))
+        project.compileDebugJavaWithJavac.dependsOn 'externalNativeBuildDebug'
+    if (project.hasProperty('compileReleaseJavaWithJavac'))
+        project.compileReleaseJavaWithJavac.dependsOn 'externalNativeBuildRelease'
+}
+
+dependencies {
+    implementation fileTree(dir: 'libs', include: ['*.jar'])
+    testImplementation 'junit:junit:4.12'
+    implementation 'com.android.support:appcompat-v7:23.1.1'
+}

subprojects/gst-docs/examples/tutorials/android/android-tutorial-4/jni/Android.mk

@@ -0,0 +1,34 @@
+LOCAL_PATH := $(call my-dir)
+
+include $(CLEAR_VARS)
+
+LOCAL_MODULE    := tutorial-4
+LOCAL_SRC_FILES := tutorial-4.c dummy.cpp
+LOCAL_SHARED_LIBRARIES := gstreamer_android
+LOCAL_LDLIBS := -llog -landroid
+include $(BUILD_SHARED_LIBRARY)
+
+ifndef GSTREAMER_ROOT_ANDROID
+$(error GSTREAMER_ROOT_ANDROID is not defined!)
+endif
+
+ifeq ($(TARGET_ARCH_ABI),armeabi)
+GSTREAMER_ROOT        := $(GSTREAMER_ROOT_ANDROID)/arm
+else ifeq ($(TARGET_ARCH_ABI),armeabi-v7a)
+GSTREAMER_ROOT        := $(GSTREAMER_ROOT_ANDROID)/armv7
+else ifeq ($(TARGET_ARCH_ABI),arm64-v8a)
+GSTREAMER_ROOT        := $(GSTREAMER_ROOT_ANDROID)/arm64
+else ifeq ($(TARGET_ARCH_ABI),x86)
+GSTREAMER_ROOT        := $(GSTREAMER_ROOT_ANDROID)/x86
+else ifeq ($(TARGET_ARCH_ABI),x86_64)
+GSTREAMER_ROOT        := $(GSTREAMER_ROOT_ANDROID)/x86_64
+else
+$(error Target arch ABI not supported: $(TARGET_ARCH_ABI))
+endif
+
+GSTREAMER_NDK_BUILD_PATH  := $(GSTREAMER_ROOT)/share/gst-android/ndk-build/
+include $(GSTREAMER_NDK_BUILD_PATH)/plugins.mk
+GSTREAMER_PLUGINS         := $(GSTREAMER_PLUGINS_CORE) $(GSTREAMER_PLUGINS_PLAYBACK) $(GSTREAMER_PLUGINS_CODECS) $(GSTREAMER_PLUGINS_NET) $(GSTREAMER_PLUGINS_SYS)
+G_IO_MODULES              := openssl
+GSTREAMER_EXTRA_DEPS      := gstreamer-video-1.0
+include $(GSTREAMER_NDK_BUILD_PATH)/gstreamer-1.0.mk

subprojects/gst-docs/examples/tutorials/android/android-tutorial-4/jni/Application.mk

@@ -0,0 +1,2 @@
+APP_ABI = armeabi armeabi-v7a arm64-v8a x86 x86_64
+APP_STL = c++_shared

subprojects/gst-docs/examples/tutorials/android/android-tutorial-4/jni/tutorial-4.c

@@ -0,0 +1,673 @@
+#include <string.h>
+#include <stdint.h>
+#include <jni.h>
+#include <android/log.h>
+#include <android/native_window.h>
+#include <android/native_window_jni.h>
+#include <gst/gst.h>
+#include <gst/video/video.h>
+#include <pthread.h>
+
+GST_DEBUG_CATEGORY_STATIC (debug_category);
+#define GST_CAT_DEFAULT debug_category
+
+/*
+ * These macros provide a way to store the native pointer to CustomData, which might be 32 or 64 bits, into
+ * a jlong, which is always 64 bits, without warnings.
+ */
+#if GLIB_SIZEOF_VOID_P == 8
+# define GET_CUSTOM_DATA(env, thiz, fieldID) (CustomData *)(*env)->GetLongField (env, thiz, fieldID)
+# define SET_CUSTOM_DATA(env, thiz, fieldID, data) (*env)->SetLongField (env, thiz, fieldID, (jlong)data)
+#else
+# define GET_CUSTOM_DATA(env, thiz, fieldID) (CustomData *)(jint)(*env)->GetLongField (env, thiz, fieldID)
+# define SET_CUSTOM_DATA(env, thiz, fieldID, data) (*env)->SetLongField (env, thiz, fieldID, (jlong)(jint)data)
+#endif
+
+/* Do not allow seeks to be performed closer than this distance. It is visually useless, and will probably
+ * confuse some demuxers. */
+#define SEEK_MIN_DELAY (500 * GST_MSECOND)
+
+/* Structure to contain all our information, so we can pass it to callbacks */
+typedef struct _CustomData
+{
+  jobject app;                  /* Application instance, used to call its methods. A global reference is kept. */
+  GstElement *pipeline;         /* The running pipeline */
+  GMainContext *context;        /* GLib context used to run the main loop */
+  GMainLoop *main_loop;         /* GLib main loop */
+  gboolean initialized;         /* To avoid informing the UI multiple times about the initialization */
+  ANativeWindow *native_window; /* The Android native window where video will be rendered */
+  GstState state;               /* Current pipeline state */
+  GstState target_state;        /* Desired pipeline state, to be set once buffering is complete */
+  gint64 duration;              /* Cached clip duration */
+  gint64 desired_position;      /* Position to seek to, once the pipeline is running */
+  GstClockTime last_seek_time;  /* For seeking overflow prevention (throttling) */
+  gboolean is_live;             /* Live streams do not use buffering */
+} CustomData;
+
+/* playbin flags */
+typedef enum
+{
+  GST_PLAY_FLAG_TEXT = (1 << 2) /* We want subtitle output */
+} GstPlayFlags;
+
+/* These global variables cache values which are not changing during execution */
+static pthread_t gst_app_thread;
+static pthread_key_t current_jni_env;
+static JavaVM *java_vm;
+static jfieldID custom_data_field_id;
+static jmethodID set_message_method_id;
+static jmethodID set_current_position_method_id;
+static jmethodID on_gstreamer_initialized_method_id;
+static jmethodID on_media_size_changed_method_id;
+
+/*
+ * Private methods
+ */
+
+/* Register this thread with the VM */
+static JNIEnv *
+attach_current_thread (void)
+{
+  JNIEnv *env;
+  JavaVMAttachArgs args;
+
+  GST_DEBUG ("Attaching thread %p", g_thread_self ());
+  args.version = JNI_VERSION_1_4;
+  args.name = NULL;
+  args.group = NULL;
+
+  if ((*java_vm)->AttachCurrentThread (java_vm, &env, &args) < 0) {
+    GST_ERROR ("Failed to attach current thread");
+    return NULL;
+  }
+
+  return env;
+}
+
+/* Unregister this thread from the VM */
+static void
+detach_current_thread (void *env)
+{
+  GST_DEBUG ("Detaching thread %p", g_thread_self ());
+  (*java_vm)->DetachCurrentThread (java_vm);
+}
+
+/* Retrieve the JNI environment for this thread */
+static JNIEnv *
+get_jni_env (void)
+{
+  JNIEnv *env;
+
+  if ((env = pthread_getspecific (current_jni_env)) == NULL) {
+    env = attach_current_thread ();
+    pthread_setspecific (current_jni_env, env);
+  }
+
+  return env;
+}
+
+/* Change the content of the UI's TextView */
+static void
+set_ui_message (const gchar * message, CustomData * data)
+{
+  JNIEnv *env = get_jni_env ();
+  GST_DEBUG ("Setting message to: %s", message);
+  jstring jmessage = (*env)->NewStringUTF (env, message);
+  (*env)->CallVoidMethod (env, data->app, set_message_method_id, jmessage);
+  if ((*env)->ExceptionCheck (env)) {
+    GST_ERROR ("Failed to call Java method");
+    (*env)->ExceptionClear (env);
+  }
+  (*env)->DeleteLocalRef (env, jmessage);
+}
+
+/* Tell the application what is the current position and clip duration */
+static void
+set_current_ui_position (gint position, gint duration, CustomData * data)
+{
+  JNIEnv *env = get_jni_env ();
+  (*env)->CallVoidMethod (env, data->app, set_current_position_method_id,
+      position, duration);
+  if ((*env)->ExceptionCheck (env)) {
+    GST_ERROR ("Failed to call Java method");
+    (*env)->ExceptionClear (env);
+  }
+}
+
+/* If we have pipeline and it is running, query the current position and clip duration and inform
+ * the application */
+static gboolean
+refresh_ui (CustomData * data)
+{
+  gint64 current = -1;
+  gint64 position;
+
+  /* We do not want to update anything unless we have a working pipeline in the PAUSED or PLAYING state */
+  if (!data || !data->pipeline || data->state < GST_STATE_PAUSED)
+    return TRUE;
+
+  /* If we didn't know it yet, query the stream duration */
+  if (!GST_CLOCK_TIME_IS_VALID (data->duration)) {
+    if (!gst_element_query_duration (data->pipeline, GST_FORMAT_TIME,
+            &data->duration)) {
+      GST_WARNING ("Could not query current duration");
+    }
+  }
+
+  if (gst_element_query_position (data->pipeline, GST_FORMAT_TIME, &position)) {
+    /* Java expects these values in milliseconds, and GStreamer provides nanoseconds */
+    set_current_ui_position (position / GST_MSECOND,
+        data->duration / GST_MSECOND, data);
+  }
+  return TRUE;
+}
+
+/* Forward declaration for the delayed seek callback */
+static gboolean delayed_seek_cb (CustomData * data);
+
+/* Perform seek, if we are not too close to the previous seek. Otherwise, schedule the seek for
+ * some time in the future. */
+static void
+execute_seek (gint64 desired_position, CustomData * data)
+{
+  gint64 diff;
+
+  if (desired_position == GST_CLOCK_TIME_NONE)
+    return;
+
+  diff = gst_util_get_timestamp () - data->last_seek_time;
+
+  if (GST_CLOCK_TIME_IS_VALID (data->last_seek_time) && diff < SEEK_MIN_DELAY) {
+    /* The previous seek was too close, delay this one */
+    GSource *timeout_source;
+
+    if (data->desired_position == GST_CLOCK_TIME_NONE) {
+      /* There was no previous seek scheduled. Setup a timer for some time in the future */
+      timeout_source =
+          g_timeout_source_new ((SEEK_MIN_DELAY - diff) / GST_MSECOND);
+      g_source_set_callback (timeout_source, (GSourceFunc) delayed_seek_cb,
+          data, NULL);
+      g_source_attach (timeout_source, data->context);
+      g_source_unref (timeout_source);
+    }
+    /* Update the desired seek position. If multiple requests are received before it is time
+     * to perform a seek, only the last one is remembered. */
+    data->desired_position = desired_position;
+    GST_DEBUG ("Throttling seek to %" GST_TIME_FORMAT ", will be in %"
+        GST_TIME_FORMAT, GST_TIME_ARGS (desired_position),
+        GST_TIME_ARGS (SEEK_MIN_DELAY - diff));
+  } else {
+    /* Perform the seek now */
+    GST_DEBUG ("Seeking to %" GST_TIME_FORMAT,
+        GST_TIME_ARGS (desired_position));
+    data->last_seek_time = gst_util_get_timestamp ();
+    gst_element_seek_simple (data->pipeline, GST_FORMAT_TIME,
+        GST_SEEK_FLAG_FLUSH | GST_SEEK_FLAG_KEY_UNIT, desired_position);
+    data->desired_position = GST_CLOCK_TIME_NONE;
+  }
+}
+
+/* Delayed seek callback. This gets called by the timer setup in the above function. */
+static gboolean
+delayed_seek_cb (CustomData * data)
+{
+  GST_DEBUG ("Doing delayed seek to %" GST_TIME_FORMAT,
+      GST_TIME_ARGS (data->desired_position));
+  execute_seek (data->desired_position, data);
+  return FALSE;
+}
+
+/* Retrieve errors from the bus and show them on the UI */
+static void
+error_cb (GstBus * bus, GstMessage * msg, CustomData * data)
+{
+  GError *err;
+  gchar *debug_info;
+  gchar *message_string;
+
+  gst_message_parse_error (msg, &err, &debug_info);
+  message_string =
+      g_strdup_printf ("Error received from element %s: %s",
+      GST_OBJECT_NAME (msg->src), err->message);
+  g_clear_error (&err);
+  g_free (debug_info);
+  set_ui_message (message_string, data);
+  g_free (message_string);
+  data->target_state = GST_STATE_NULL;
+  gst_element_set_state (data->pipeline, GST_STATE_NULL);
+}
+
+/* Called when the End Of the Stream is reached. Just move to the beginning of the media and pause. */
+static void
+eos_cb (GstBus * bus, GstMessage * msg, CustomData * data)
+{
+  data->target_state = GST_STATE_PAUSED;
+  data->is_live =
+      (gst_element_set_state (data->pipeline,
+          GST_STATE_PAUSED) == GST_STATE_CHANGE_NO_PREROLL);
+  execute_seek (0, data);
+}
+
+/* Called when the duration of the media changes. Just mark it as unknown, so we re-query it in the next UI refresh. */
+static void
+duration_cb (GstBus * bus, GstMessage * msg, CustomData * data)
+{
+  data->duration = GST_CLOCK_TIME_NONE;
+}
+
+/* Called when buffering messages are received. We inform the UI about the current buffering level and
+ * keep the pipeline paused until 100% buffering is reached. At that point, set the desired state. */
+static void
+buffering_cb (GstBus * bus, GstMessage * msg, CustomData * data)
+{
+  gint percent;
+
+  if (data->is_live)
+    return;
+
+  gst_message_parse_buffering (msg, &percent);
+  if (percent < 100 && data->target_state >= GST_STATE_PAUSED) {
+    gchar *message_string = g_strdup_printf ("Buffering %d%%", percent);
+    gst_element_set_state (data->pipeline, GST_STATE_PAUSED);
+    set_ui_message (message_string, data);
+    g_free (message_string);
+  } else if (data->target_state >= GST_STATE_PLAYING) {
+    gst_element_set_state (data->pipeline, GST_STATE_PLAYING);
+  } else if (data->target_state >= GST_STATE_PAUSED) {
+    set_ui_message ("Buffering complete", data);
+  }
+}
+
+/* Called when the clock is lost */
+static void
+clock_lost_cb (GstBus * bus, GstMessage * msg, CustomData * data)
+{
+  if (data->target_state >= GST_STATE_PLAYING) {
+    gst_element_set_state (data->pipeline, GST_STATE_PAUSED);
+    gst_element_set_state (data->pipeline, GST_STATE_PLAYING);
+  }
+}
+
+/* Retrieve the video sink's Caps and tell the application about the media size */
+static void
+check_media_size (CustomData * data)
+{
+  JNIEnv *env = get_jni_env ();
+  GstElement *video_sink;
+  GstPad *video_sink_pad;
+  GstCaps *caps;
+  GstVideoInfo info;
+
+  /* Retrieve the Caps at the entrance of the video sink */
+  g_object_get (data->pipeline, "video-sink", &video_sink, NULL);
+  video_sink_pad = gst_element_get_static_pad (video_sink, "sink");
+  caps = gst_pad_get_current_caps (video_sink_pad);
+
+  if (gst_video_info_from_caps (&info, caps)) {
+    info.width = info.width * info.par_n / info.par_d;
+    GST_DEBUG ("Media size is %dx%d, notifying application", info.width,
+        info.height);
+
+    (*env)->CallVoidMethod (env, data->app, on_media_size_changed_method_id,
+        (jint) info.width, (jint) info.height);
+    if ((*env)->ExceptionCheck (env)) {
+      GST_ERROR ("Failed to call Java method");
+      (*env)->ExceptionClear (env);
+    }
+  }
+
+  gst_caps_unref (caps);
+  gst_object_unref (video_sink_pad);
+  gst_object_unref (video_sink);
+}
+
+/* Notify UI about pipeline state changes */
+static void
+state_changed_cb (GstBus * bus, GstMessage * msg, CustomData * data)
+{
+  GstState old_state, new_state, pending_state;
+  gst_message_parse_state_changed (msg, &old_state, &new_state, &pending_state);
+  /* Only pay attention to messages coming from the pipeline, not its children */
+  if (GST_MESSAGE_SRC (msg) == GST_OBJECT (data->pipeline)) {
+    data->state = new_state;
+    gchar *message = g_strdup_printf ("State changed to %s",
+        gst_element_state_get_name (new_state));
+    set_ui_message (message, data);
+    g_free (message);
+
+    /* The Ready to Paused state change is particularly interesting: */
+    if (old_state == GST_STATE_READY && new_state == GST_STATE_PAUSED) {
+      /* By now the sink already knows the media size */
+      check_media_size (data);
+
+      /* If there was a scheduled seek, perform it now that we have moved to the Paused state */
+      if (GST_CLOCK_TIME_IS_VALID (data->desired_position))
+        execute_seek (data->desired_position, data);
+    }
+  }
+}
+
+/* Check if all conditions are met to report GStreamer as initialized.
+ * These conditions will change depending on the application */
+static void
+check_initialization_complete (CustomData * data)
+{
+  JNIEnv *env = get_jni_env ();
+  if (!data->initialized && data->native_window && data->main_loop) {
+    GST_DEBUG
+        ("Initialization complete, notifying application. native_window:%p main_loop:%p",
+        data->native_window, data->main_loop);
+
+    /* The main loop is running and we received a native window, inform the sink about it */
+    gst_video_overlay_set_window_handle (GST_VIDEO_OVERLAY (data->pipeline),
+        (guintptr) data->native_window);
+
+    (*env)->CallVoidMethod (env, data->app, on_gstreamer_initialized_method_id);
+    if ((*env)->ExceptionCheck (env)) {
+      GST_ERROR ("Failed to call Java method");
+      (*env)->ExceptionClear (env);
+    }
+    data->initialized = TRUE;
+  }
+}
+
+/* Main method for the native code. This is executed on its own thread. */
+static void *
+app_function (void *userdata)
+{
+  JavaVMAttachArgs args;
+  GstBus *bus;
+  CustomData *data = (CustomData *) userdata;
+  GSource *timeout_source;
+  GSource *bus_source;
+  GError *error = NULL;
+  guint flags;
+
+  GST_DEBUG ("Creating pipeline in CustomData at %p", data);
+
+  /* Create our own GLib Main Context and make it the default one */
+  data->context = g_main_context_new ();
+  g_main_context_push_thread_default (data->context);
+
+  /* Build pipeline */
+  data->pipeline = gst_parse_launch ("playbin", &error);
+  if (error) {
+    gchar *message =
+        g_strdup_printf ("Unable to build pipeline: %s", error->message);
+    g_clear_error (&error);
+    set_ui_message (message, data);
+    g_free (message);
+    return NULL;
+  }
+
+  /* Disable subtitles */
+  g_object_get (data->pipeline, "flags", &flags, NULL);
+  flags &= ~GST_PLAY_FLAG_TEXT;
+  g_object_set (data->pipeline, "flags", flags, NULL);
+
+  /* Set the pipeline to READY, so it can already accept a window handle, if we have one */
+  data->target_state = GST_STATE_READY;
+  gst_element_set_state (data->pipeline, GST_STATE_READY);
+
+  /* Instruct the bus to emit signals for each received message, and connect to the interesting signals */
+  bus = gst_element_get_bus (data->pipeline);
+  bus_source = gst_bus_create_watch (bus);
+  g_source_set_callback (bus_source, (GSourceFunc) gst_bus_async_signal_func,
+      NULL, NULL);
+  g_source_attach (bus_source, data->context);
+  g_source_unref (bus_source);
+  g_signal_connect (G_OBJECT (bus), "message::error", (GCallback) error_cb,
+      data);
+  g_signal_connect (G_OBJECT (bus), "message::eos", (GCallback) eos_cb, data);
+  g_signal_connect (G_OBJECT (bus), "message::state-changed",
+      (GCallback) state_changed_cb, data);
+  g_signal_connect (G_OBJECT (bus), "message::duration",
+      (GCallback) duration_cb, data);
+  g_signal_connect (G_OBJECT (bus), "message::buffering",
+      (GCallback) buffering_cb, data);
+  g_signal_connect (G_OBJECT (bus), "message::clock-lost",
+      (GCallback) clock_lost_cb, data);
+  gst_object_unref (bus);
+
+  /* Register a function that GLib will call 4 times per second */
+  timeout_source = g_timeout_source_new (250);
+  g_source_set_callback (timeout_source, (GSourceFunc) refresh_ui, data, NULL);
+  g_source_attach (timeout_source, data->context);
+  g_source_unref (timeout_source);
+
+  /* Create a GLib Main Loop and set it to run */
+  GST_DEBUG ("Entering main loop... (CustomData:%p)", data);
+  data->main_loop = g_main_loop_new (data->context, FALSE);
+  check_initialization_complete (data);
+  g_main_loop_run (data->main_loop);
+  GST_DEBUG ("Exited main loop");
+  g_main_loop_unref (data->main_loop);
+  data->main_loop = NULL;
+
+  /* Free resources */
+  g_main_context_pop_thread_default (data->context);
+  g_main_context_unref (data->context);
+  data->target_state = GST_STATE_NULL;
+  gst_element_set_state (data->pipeline, GST_STATE_NULL);
+  gst_object_unref (data->pipeline);
+
+  return NULL;
+}
+
+/*
+ * Java Bindings
+ */
+
+/* Instruct the native code to create its internal data structure, pipeline and thread */
+static void
+gst_native_init (JNIEnv * env, jobject thiz)
+{
+  CustomData *data = g_new0 (CustomData, 1);
+  data->desired_position = GST_CLOCK_TIME_NONE;
+  data->last_seek_time = GST_CLOCK_TIME_NONE;
+  SET_CUSTOM_DATA (env, thiz, custom_data_field_id, data);
+  GST_DEBUG_CATEGORY_INIT (debug_category, "tutorial-4", 0,
+      "Android tutorial 4");
+  gst_debug_set_threshold_for_name ("tutorial-4", GST_LEVEL_DEBUG);
+  GST_DEBUG ("Created CustomData at %p", data);
+  data->app = (*env)->NewGlobalRef (env, thiz);
+  GST_DEBUG ("Created GlobalRef for app object at %p", data->app);
+  pthread_create (&gst_app_thread, NULL, &app_function, data);
+}
+
+/* Quit the main loop, remove the native thread and free resources */
+static void
+gst_native_finalize (JNIEnv * env, jobject thiz)
+{
+  CustomData *data = GET_CUSTOM_DATA (env, thiz, custom_data_field_id);
+  if (!data)
+    return;
+  GST_DEBUG ("Quitting main loop...");
+  g_main_loop_quit (data->main_loop);
+  GST_DEBUG ("Waiting for thread to finish...");
+  pthread_join (gst_app_thread, NULL);
+  GST_DEBUG ("Deleting GlobalRef for app object at %p", data->app);
+  (*env)->DeleteGlobalRef (env, data->app);
+  GST_DEBUG ("Freeing CustomData at %p", data);
+  g_free (data);
+  SET_CUSTOM_DATA (env, thiz, custom_data_field_id, NULL);
+  GST_DEBUG ("Done finalizing");
+}
+
+/* Set playbin's URI */
+void
+gst_native_set_uri (JNIEnv * env, jobject thiz, jstring uri)
+{
+  CustomData *data = GET_CUSTOM_DATA (env, thiz, custom_data_field_id);
+  if (!data || !data->pipeline)
+    return;
+  const gchar *char_uri = (*env)->GetStringUTFChars (env, uri, NULL);
+  GST_DEBUG ("Setting URI to %s", char_uri);
+  if (data->target_state >= GST_STATE_READY)
+    gst_element_set_state (data->pipeline, GST_STATE_READY);
+  g_object_set (data->pipeline, "uri", char_uri, NULL);
+  (*env)->ReleaseStringUTFChars (env, uri, char_uri);
+  data->duration = GST_CLOCK_TIME_NONE;
+  data->is_live =
+      (gst_element_set_state (data->pipeline,
+          data->target_state) == GST_STATE_CHANGE_NO_PREROLL);
+}
+
+/* Set pipeline to PLAYING state */
+static void
+gst_native_play (JNIEnv * env, jobject thiz)
+{
+  CustomData *data = GET_CUSTOM_DATA (env, thiz, custom_data_field_id);
+  if (!data)
+    return;
+  GST_DEBUG ("Setting state to PLAYING");
+  data->target_state = GST_STATE_PLAYING;
+  data->is_live =
+      (gst_element_set_state (data->pipeline,
+          GST_STATE_PLAYING) == GST_STATE_CHANGE_NO_PREROLL);
+}
+
+/* Set pipeline to PAUSED state */
+static void
+gst_native_pause (JNIEnv * env, jobject thiz)
+{
+  CustomData *data = GET_CUSTOM_DATA (env, thiz, custom_data_field_id);
+  if (!data)
+    return;
+  GST_DEBUG ("Setting state to PAUSED");
+  data->target_state = GST_STATE_PAUSED;
+  data->is_live =
+      (gst_element_set_state (data->pipeline,
+          GST_STATE_PAUSED) == GST_STATE_CHANGE_NO_PREROLL);
+}
+
+/* Instruct the pipeline to seek to a different position */
+void
+gst_native_set_position (JNIEnv * env, jobject thiz, int milliseconds)
+{
+  CustomData *data = GET_CUSTOM_DATA (env, thiz, custom_data_field_id);
+  if (!data)
+    return;
+  gint64 desired_position = (gint64) (milliseconds * GST_MSECOND);
+  if (data->state >= GST_STATE_PAUSED) {
+    execute_seek (desired_position, data);
+  } else {
+    GST_DEBUG ("Scheduling seek to %" GST_TIME_FORMAT " for later",
+        GST_TIME_ARGS (desired_position));
+    data->desired_position = desired_position;
+  }
+}
+
+/* Static class initializer: retrieve method and field IDs */
+static jboolean
+gst_native_class_init (JNIEnv * env, jclass klass)
+{
+  custom_data_field_id =
+      (*env)->GetFieldID (env, klass, "native_custom_data", "J");
+  set_message_method_id =
+      (*env)->GetMethodID (env, klass, "setMessage", "(Ljava/lang/String;)V");
+  set_current_position_method_id =
+      (*env)->GetMethodID (env, klass, "setCurrentPosition", "(II)V");
+  on_gstreamer_initialized_method_id =
+      (*env)->GetMethodID (env, klass, "onGStreamerInitialized", "()V");
+  on_media_size_changed_method_id =
+      (*env)->GetMethodID (env, klass, "onMediaSizeChanged", "(II)V");
+
+  if (!custom_data_field_id || !set_message_method_id
+      || !on_gstreamer_initialized_method_id || !on_media_size_changed_method_id
+      || !set_current_position_method_id) {
+    /* We emit this message through the Android log instead of the GStreamer log because the later
+     * has not been initialized yet.
+     */
+    __android_log_print (ANDROID_LOG_ERROR, "tutorial-4",
+        "The calling class does not implement all necessary interface methods");
+    return JNI_FALSE;
+  }
+  return JNI_TRUE;
+}
+
+static void
+gst_native_surface_init (JNIEnv * env, jobject thiz, jobject surface)
+{
+  CustomData *data = GET_CUSTOM_DATA (env, thiz, custom_data_field_id);
+  if (!data)
+    return;
+  ANativeWindow *new_native_window = ANativeWindow_fromSurface (env, surface);
+  GST_DEBUG ("Received surface %p (native window %p)", surface,
+      new_native_window);
+
+  if (data->native_window) {
+    ANativeWindow_release (data->native_window);
+    if (data->native_window == new_native_window) {
+      GST_DEBUG ("New native window is the same as the previous one %p",
+          data->native_window);
+      if (data->pipeline) {
+        gst_video_overlay_expose (GST_VIDEO_OVERLAY (data->pipeline));
+        gst_video_overlay_expose (GST_VIDEO_OVERLAY (data->pipeline));
+      }
+      return;
+    } else {
+      GST_DEBUG ("Released previous native window %p", data->native_window);
+      data->initialized = FALSE;
+    }
+  }
+  data->native_window = new_native_window;
+
+  check_initialization_complete (data);
+}
+
+static void
+gst_native_surface_finalize (JNIEnv * env, jobject thiz)
+{
+  CustomData *data = GET_CUSTOM_DATA (env, thiz, custom_data_field_id);
+  if (!data)
+    return;
+  GST_DEBUG ("Releasing Native Window %p", data->native_window);
+
+  if (data->pipeline) {
+    gst_video_overlay_set_window_handle (GST_VIDEO_OVERLAY (data->pipeline),
+        (guintptr) NULL);
+    gst_element_set_state (data->pipeline, GST_STATE_READY);
+  }
+
+  ANativeWindow_release (data->native_window);
+  data->native_window = NULL;
+  data->initialized = FALSE;
+}
+
+/* List of implemented native methods */
+static JNINativeMethod native_methods[] = {
+  {"nativeInit", "()V", (void *) gst_native_init},
+  {"nativeFinalize", "()V", (void *) gst_native_finalize},
+  {"nativeSetUri", "(Ljava/lang/String;)V", (void *) gst_native_set_uri},
+  {"nativePlay", "()V", (void *) gst_native_play},
+  {"nativePause", "()V", (void *) gst_native_pause},
+  {"nativeSetPosition", "(I)V", (void *) gst_native_set_position},
+  {"nativeSurfaceInit", "(Ljava/lang/Object;)V",
+      (void *) gst_native_surface_init},
+  {"nativeSurfaceFinalize", "()V", (void *) gst_native_surface_finalize},
+  {"nativeClassInit", "()Z", (void *) gst_native_class_init}
+};
+
+/* Library initializer */
+jint
+JNI_OnLoad (JavaVM * vm, void *reserved)
+{
+  JNIEnv *env = NULL;
+
+  java_vm = vm;
+
+  if ((*vm)->GetEnv (vm, (void **) &env, JNI_VERSION_1_4) != JNI_OK) {
+    __android_log_print (ANDROID_LOG_ERROR, "tutorial-4",
+        "Could not retrieve JNIEnv");
+    return 0;
+  }
+  jclass klass = (*env)->FindClass (env,
+      "org/freedesktop/gstreamer/tutorials/tutorial_4/Tutorial4");
+  (*env)->RegisterNatives (env, klass, native_methods,
+      G_N_ELEMENTS (native_methods));
+
+  pthread_key_create (&current_jni_env, detach_current_thread);
+
+  return JNI_VERSION_1_4;
+}

subprojects/gst-docs/examples/tutorials/android/android-tutorial-4/res/layout/main.xml

@@ -0,0 +1,69 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:gravity="center_vertical"
+    android:orientation="vertical" >
+
+    <TextView
+        android:id="@+id/textview_message"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginBottom="16dip"
+        android:gravity="center_horizontal" />
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginBottom="16dip"
+        android:gravity="center_horizontal"
+        android:orientation="horizontal" >
+
+        <ImageButton
+            android:id="@+id/button_play"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:contentDescription="@string/button_play"
+            android:src="@android:drawable/ic_media_play"
+            android:text="@string/button_play" />
+
+        <ImageButton
+            android:id="@+id/button_stop"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:contentDescription="@string/button_stop"
+            android:src="@android:drawable/ic_media_pause"
+            android:text="@string/button_stop" />
+    </LinearLayout>
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginBottom="16dip"
+        android:gravity="center_horizontal"
+        android:orientation="horizontal" >
+
+        <TextView
+            android:id="@+id/textview_time"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_gravity="center_vertical"
+            android:layout_marginLeft="5dip"
+            android:layout_marginRight="5dip" />
+
+        <SeekBar
+            android:id="@+id/seek_bar"
+            android:layout_width="0dip"
+            android:layout_height="wrap_content"
+            android:layout_gravity="center_vertical"
+            android:layout_weight="1"
+            android:indeterminate="false" />
+    </LinearLayout>
+
+    <org.freedesktop.gstreamer.tutorials.tutorial_4.GStreamerSurfaceView
+        android:id="@+id/surface_video"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_gravity="center_vertical|center_horizontal" />
+
+</LinearLayout>

subprojects/gst-docs/examples/tutorials/android/android-tutorial-4/res/values/strings.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <string name="app_name">GStreamer tutorial 4</string>
+    <string name="button_play">Play</string>
+    <string name="button_stop">Stop</string>
+</resources>