androidmedia: Split jni code to gstjniutils.c

4 files changed, 676 insertions, 583 deletions

diff --git a/sys/androidmedia/Makefile.am b/sys/androidmedia/Makefile.am
index 3f1758803..937ce32ac 100644
--- a/sys/androidmedia/Makefile.am
+++ b/sys/androidmedia/Makefile.am
@@ -4,14 +4,16 @@ libgstandroidmedia_la_SOURCES = \
 	gstamc.c \
 	gstamcaudiodec.c \
 	gstamcvideodec.c \
-	gstamcvideoenc.c
+	gstamcvideoenc.c \
+	gstjniutils.c
 
 noinst_HEADERS = \
 	gstamc.h \
 	gstamc-constants.h \
 	gstamcaudiodec.h \
 	gstamcvideodec.h \
-	gstamcvideoenc.h
+	gstamcvideoenc.h \
+	gstjniutils.h
 
 libgstandroidmedia_la_CFLAGS = \
 	$(GST_PLUGINS_BASE_CFLAGS) \
diff --git a/sys/androidmedia/gstamc.c b/sys/androidmedia/gstamc.c
index 36e437285..57024f27a 100644
--- a/sys/androidmedia/gstamc.c
+++ b/sys/androidmedia/gstamc.c
@@ -34,215 +34,12 @@
 #include "gstamcvideodec.h"
 #include "gstamcvideoenc.h"
 #include "gstamcaudiodec.h"
+#include "gstjniutils.h"
 
-#include <gmodule.h>
 #include <gst/gst.h>
 #include <gst/video/video.h>
 #include <gst/audio/audio.h>
 #include <string.h>
-#include <jni.h>
-
-/* getExceptionSummary() and getStackTrace() taken from Android's
- *   platform/libnativehelper/JNIHelp.cpp
- * Modified to work with normal C strings and without C++.
- *
- * Copyright (C) 2006 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-/*
- * Returns a human-readable summary of an exception object. The buffer will
- * be populated with the "binary" class name and, if present, the
- * exception message.
- */
-static gchar *
-getExceptionSummary (JNIEnv * env, jthrowable exception)
-{
-  GString *gs = g_string_new ("");
-  jclass exceptionClass = NULL, classClass = NULL;
-  jmethodID classGetNameMethod, getMessage;
-  jstring classNameStr = NULL, messageStr = NULL;
-  const char *classNameChars, *messageChars;
-
-  /* get the name of the exception's class */
-  exceptionClass = (*env)->GetObjectClass (env, exception);
-  classClass = (*env)->GetObjectClass (env, exceptionClass);
-  classGetNameMethod =
-      (*env)->GetMethodID (env, classClass, "getName", "()Ljava/lang/String;");
-
-  classNameStr =
-      (jstring) (*env)->CallObjectMethod (env, exceptionClass,
-      classGetNameMethod);
-
-  if (classNameStr == NULL) {
-    if ((*env)->ExceptionCheck (env))
-      (*env)->ExceptionClear (env);
-    g_string_append (gs, "<error getting class name>");
-    goto done;
-  }
-
-  classNameChars = (*env)->GetStringUTFChars (env, classNameStr, NULL);
-  if (classNameChars == NULL) {
-    if ((*env)->ExceptionCheck (env))
-      (*env)->ExceptionClear (env);
-    g_string_append (gs, "<error getting class name UTF-8>");
-    goto done;
-  }
-
-  g_string_append (gs, classNameChars);
-
-  (*env)->ReleaseStringUTFChars (env, classNameStr, classNameChars);
-
-  /* if the exception has a detail message, get that */
-  getMessage =
-      (*env)->GetMethodID (env, exceptionClass, "getMessage",
-      "()Ljava/lang/String;");
-  messageStr = (jstring) (*env)->CallObjectMethod (env, exception, getMessage);
-  if (messageStr == NULL) {
-    if ((*env)->ExceptionCheck (env))
-      (*env)->ExceptionClear (env);
-    goto done;
-  }
-  g_string_append (gs, ": ");
-
-  messageChars = (*env)->GetStringUTFChars (env, messageStr, NULL);
-  if (messageChars != NULL) {
-    g_string_append (gs, messageChars);
-    (*env)->ReleaseStringUTFChars (env, messageStr, messageChars);
-  } else {
-    if ((*env)->ExceptionCheck (env))
-      (*env)->ExceptionClear (env);
-    g_string_append (gs, "<error getting message>");
-  }
-
-done:
-  if (exceptionClass)
-    (*env)->DeleteLocalRef (env, exceptionClass);
-  if (classClass)
-    (*env)->DeleteLocalRef (env, classClass);
-  if (classNameStr)
-    (*env)->DeleteLocalRef (env, classNameStr);
-  if (messageStr)
-    (*env)->DeleteLocalRef (env, messageStr);
-
-  return g_string_free (gs, FALSE);
-}
-
-/*
- * Returns an exception (with stack trace) as a string.
- */
-static gchar *
-getStackTrace (JNIEnv * env, jthrowable exception)
-{
-  GString *gs = g_string_new ("");
-  jclass stringWriterClass = NULL, printWriterClass = NULL;
-  jclass exceptionClass = NULL;
-  jmethodID stringWriterCtor, stringWriterToStringMethod;
-  jmethodID printWriterCtor, printStackTraceMethod;
-  jobject stringWriter = NULL, printWriter = NULL;
-  jstring messageStr = NULL;
-  const char *utfChars;
-
-  stringWriterClass = (*env)->FindClass (env, "java/io/StringWriter");
-
-  if (stringWriterClass == NULL) {
-    g_string_append (gs, "<error getting java.io.StringWriter class>");
-    goto done;
-  }
-
-  stringWriterCtor =
-      (*env)->GetMethodID (env, stringWriterClass, "<init>", "()V");
-  stringWriterToStringMethod =
-      (*env)->GetMethodID (env, stringWriterClass, "toString",
-      "()Ljava/lang/String;");
-
-  printWriterClass = (*env)->FindClass (env, "java/io/PrintWriter");
-  if (printWriterClass == NULL) {
-    g_string_append (gs, "<error getting java.io.PrintWriter class>");
-    goto done;
-  }
-
-  printWriterCtor =
-      (*env)->GetMethodID (env, printWriterClass, "<init>",
-      "(Ljava/io/Writer;)V");
-  stringWriter = (*env)->NewObject (env, stringWriterClass, stringWriterCtor);
-  if (stringWriter == NULL) {
-    if ((*env)->ExceptionCheck (env))
-      (*env)->ExceptionClear (env);
-    g_string_append (gs, "<error creating new StringWriter instance>");
-    goto done;
-  }
-
-  printWriter =
-      (*env)->NewObject (env, printWriterClass, printWriterCtor, stringWriter);
-  if (printWriter == NULL) {
-    if ((*env)->ExceptionCheck (env))
-      (*env)->ExceptionClear (env);
-    g_string_append (gs, "<error creating new PrintWriter instance>");
-    goto done;
-  }
-
-  exceptionClass = (*env)->GetObjectClass (env, exception);
-  printStackTraceMethod =
-      (*env)->GetMethodID (env, exceptionClass, "printStackTrace",
-      "(Ljava/io/PrintWriter;)V");
-  (*env)->CallVoidMethod (env, exception, printStackTraceMethod, printWriter);
-  if ((*env)->ExceptionCheck (env)) {
-    (*env)->ExceptionClear (env);
-    g_string_append (gs, "<exception while printing stack trace>");
-    goto done;
-  }
-
-  messageStr = (jstring) (*env)->CallObjectMethod (env, stringWriter,
-      stringWriterToStringMethod);
-  if (messageStr == NULL) {
-    if ((*env)->ExceptionCheck (env))
-      (*env)->ExceptionClear (env);
-    g_string_append (gs, "<failed to call StringWriter.toString()>");
-    goto done;
-  }
-
-  utfChars = (*env)->GetStringUTFChars (env, messageStr, NULL);
-  if (utfChars == NULL) {
-    if ((*env)->ExceptionCheck (env))
-      (*env)->ExceptionClear (env);
-    g_string_append (gs, "<failed to get UTF chars for message>");
-    goto done;
-  }
-
-  g_string_append (gs, utfChars);
-
-  (*env)->ReleaseStringUTFChars (env, messageStr, utfChars);
-
-done:
-  if (stringWriterClass)
-    (*env)->DeleteLocalRef (env, stringWriterClass);
-  if (printWriterClass)
-    (*env)->DeleteLocalRef (env, printWriterClass);
-  if (exceptionClass)
-    (*env)->DeleteLocalRef (env, exceptionClass);
-  if (stringWriter)
-    (*env)->DeleteLocalRef (env, stringWriter);
-  if (printWriter)
-    (*env)->DeleteLocalRef (env, printWriter);
-  if (messageStr)
-    (*env)->DeleteLocalRef (env, messageStr);
-
-  return g_string_free (gs, FALSE);
-}
-
-#include <pthread.h>
 
 GST_DEBUG_CATEGORY (gst_amc_debug);
 #define GST_CAT_DEFAULT gst_amc_debug
@@ -256,13 +53,6 @@ static gboolean ignore_unknown_color_formats = TRUE;
 static gboolean ignore_unknown_color_formats = FALSE;
 #endif
 
-static GModule *java_module;
-static jint (*get_created_java_vms) (JavaVM ** vmBuf, jsize bufLen,
-    jsize * nVMs);
-static jint (*create_java_vm) (JavaVM ** p_vm, JNIEnv ** p_env, void *vm_args);
-static JavaVM *java_vm;
-static gboolean started_java_vm = FALSE;
-
 static gboolean accepted_color_formats (GstAmcCodecType * type,
     gboolean is_encoder);
 
@@ -315,233 +105,6 @@ static struct
   jmethodID set_byte_buffer;
 } media_format;
 
-static pthread_key_t current_jni_env;
-
-static JNIEnv *
-gst_amc_attach_current_thread (void)
-{
-  JNIEnv *env;
-  JavaVMAttachArgs args;
-
-  GST_DEBUG ("Attaching thread %p", g_thread_self ());
-  args.version = JNI_VERSION_1_6;
-  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;
-}
-
-static void
-gst_amc_detach_current_thread (void *env)
-{
-  GST_DEBUG ("Detaching thread %p", g_thread_self ());
-  (*java_vm)->DetachCurrentThread (java_vm);
-}
-
-static JNIEnv *
-gst_amc_get_jni_env (void)
-{
-  JNIEnv *env;
-
-  if ((env = pthread_getspecific (current_jni_env)) == NULL) {
-    env = gst_amc_attach_current_thread ();
-    pthread_setspecific (current_jni_env, env);
-  }
-
-  return env;
-}
-
-static gboolean
-check_nativehelper (void)
-{
-  GModule *module;
-  void **jni_invocation = NULL;
-  gboolean ret = FALSE;
-
-  module = g_module_open (NULL, G_MODULE_BIND_LOCAL);
-  if (!module)
-    return ret;
-
-  /* Check if libnativehelper is loaded in the process and if
-   * it has these awful wrappers for JNI_CreateJavaVM and
-   * JNI_GetCreatedJavaVMs that crash the app if you don't
-   * create a JniInvocation instance first. If it isn't we
-   * just fail here and don't initialize anything.
-   * See this code for reference:
-   * https://android.googlesource.com/platform/libnativehelper/+/master/JniInvocation.cpp
-   */
-  if (!g_module_symbol (module, "_ZN13JniInvocation15jni_invocation_E",
-          (gpointer *) & jni_invocation)) {
-    ret = TRUE;
-  } else {
-    ret = (jni_invocation != NULL && *jni_invocation != NULL);
-  }
-
-  g_module_close (module);
-
-  return ret;
-}
-
-static gboolean
-load_java_module (const gchar * name)
-{
-  java_module = g_module_open (name, G_MODULE_BIND_LOCAL);
-  if (!java_module)
-    goto load_failed;
-
-  if (!g_module_symbol (java_module, "JNI_CreateJavaVM",
-          (gpointer *) & create_java_vm))
-    goto symbol_error;
-
-  if (!g_module_symbol (java_module, "JNI_GetCreatedJavaVMs",
-          (gpointer *) & get_created_java_vms))
-    goto symbol_error;
-
-  return TRUE;
-
-load_failed:
-  {
-    GST_ERROR ("Failed to load Java module '%s': %s", GST_STR_NULL (name),
-        g_module_error ());
-    return FALSE;
-  }
-symbol_error:
-  {
-    GST_ERROR ("Failed to locate required JNI symbols in '%s': %s",
-        GST_STR_NULL (name), g_module_error ());
-    g_module_close (java_module);
-    java_module = NULL;
-    return FALSE;
-  }
-}
-
-static gboolean
-initialize_java_vm (void)
-{
-  jsize n_vms;
-
-  /* Returns TRUE if we can safely
-   * a) get the current VMs and
-   * b) start a VM if none is started yet
-   *
-   * FIXME: On Android >= 4.4 we won't be able to safely start a
-   * VM on our own without using private C++ API!
-   */
-  if (!check_nativehelper ()) {
-    GST_ERROR ("Can't safely check for VMs or start a VM");
-    return FALSE;
-  }
-
-  if (!load_java_module (NULL)) {
-    if (!load_java_module ("libdvm"))
-      return FALSE;
-  }
-
-  n_vms = 0;
-  if (get_created_java_vms (&java_vm, 1, &n_vms) < 0)
-    goto get_created_failed;
-
-  if (n_vms > 0) {
-    GST_DEBUG ("Successfully got existing Java VM %p", java_vm);
-  } else {
-    JNIEnv *env;
-    JavaVMInitArgs vm_args;
-    JavaVMOption options[4];
-
-    GST_DEBUG ("Found no existing Java VM, trying to start one");
-
-    options[0].optionString = "-verbose:jni";
-    options[1].optionString = "-verbose:gc";
-    options[2].optionString = "-Xcheck:jni";
-    options[3].optionString = "-Xdebug";
-
-    vm_args.version = JNI_VERSION_1_4;
-    vm_args.options = options;
-    vm_args.nOptions = 4;
-    vm_args.ignoreUnrecognized = JNI_TRUE;
-    if (create_java_vm (&java_vm, &env, &vm_args) < 0)
-      goto create_failed;
-    GST_DEBUG ("Successfully created Java VM %p", java_vm);
-
-    started_java_vm = TRUE;
-  }
-
-  return java_vm != NULL;
-
-get_created_failed:
-  {
-    GST_ERROR ("Failed to get already created VMs");
-    g_module_close (java_module);
-    java_module = NULL;
-    return FALSE;
-  }
-create_failed:
-  {
-    GST_ERROR ("Failed to create a Java VM");
-    g_module_close (java_module);
-    java_module = NULL;
-    return FALSE;
-  }
-}
-
-static void
-gst_amc_set_error_string (JNIEnv * env, GQuark domain, gint code, GError ** err,
-    const gchar * message)
-{
-  jthrowable exception;
-
-  if (!err) {
-    if ((*env)->ExceptionCheck (env))
-      (*env)->ExceptionClear (env);
-    return;
-  }
-
-  if ((*env)->ExceptionCheck (env)) {
-    if ((exception = (*env)->ExceptionOccurred (env))) {
-      gchar *exception_description, *exception_stacktrace;
-
-      /* Clear exception so that we can call Java methods again */
-      (*env)->ExceptionClear (env);
-
-      exception_description = getExceptionSummary (env, exception);
-      exception_stacktrace = getStackTrace (env, exception);
-      g_set_error (err, domain, code, "%s: %s\n%s", message,
-          exception_description, exception_stacktrace);
-      g_free (exception_description);
-      g_free (exception_stacktrace);
-
-      (*env)->DeleteLocalRef (env, exception);
-    } else {
-      (*env)->ExceptionClear (env);
-      g_set_error (err, domain, code, "%s", message);
-    }
-  } else {
-    g_set_error (err, domain, code, "%s", message);
-  }
-}
-
-G_GNUC_PRINTF (5, 6)
-     static void
-         gst_amc_set_error (JNIEnv * env, GQuark domain, gint code,
-    GError ** err, const gchar * format, ...)
-{
-  gchar *message;
-  va_list var_args;
-
-  va_start (var_args, format);
-  message = g_strdup_vprintf (format, var_args);
-  va_end (var_args);
-
-  gst_amc_set_error_string (env, domain, code, err, message);
-
-  g_free (message);
-}
-
 GstAmcCodec *
 gst_amc_codec_new (const gchar * name, GError ** err)
 {
@@ -552,11 +115,11 @@ gst_amc_codec_new (const gchar * name, GError ** err)
 
   g_return_val_if_fail (name != NULL, NULL);
 
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   name_str = (*env)->NewStringUTF (env, name);
   if (name_str == NULL) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_INIT, err,
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_INIT, err,
         "Failed to create Java String");
     goto error;
   }
@@ -567,14 +130,14 @@ gst_amc_codec_new (const gchar * name, GError ** err)
       (*env)->CallStaticObjectMethod (env, media_codec.klass,
       media_codec.create_by_codec_name, name_str);
   if ((*env)->ExceptionCheck (env) || !object) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_INIT, err,
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_INIT, err,
         "Failed to create codec '%s'", name);
     goto error;
   }
 
   codec->object = (*env)->NewGlobalRef (env, object);
   if (!codec->object) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_INIT, err,
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_INIT, err,
         "Failed to create global codec reference");
     goto error;
   }
@@ -602,7 +165,7 @@ gst_amc_codec_free (GstAmcCodec * codec)
 
   g_return_if_fail (codec != NULL);
 
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
   (*env)->DeleteGlobalRef (env, codec->object);
   g_slice_free (GstAmcCodec, codec);
 }
@@ -617,13 +180,13 @@ gst_amc_codec_configure (GstAmcCodec * codec, GstAmcFormat * format, gint flags,
   g_return_val_if_fail (codec != NULL, FALSE);
   g_return_val_if_fail (format != NULL, FALSE);
 
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   (*env)->CallVoidMethod (env, codec->object, media_codec.configure,
       format->object, NULL, NULL, flags);
   if ((*env)->ExceptionCheck (env)) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_SETTINGS, err,
-        "Failed to configure codec");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_SETTINGS,
+        err, "Failed to configure codec");
     ret = FALSE;
     goto done;
   }
@@ -642,14 +205,14 @@ gst_amc_codec_get_output_format (GstAmcCodec * codec, GError ** err)
 
   g_return_val_if_fail (codec != NULL, NULL);
 
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   object =
       (*env)->CallObjectMethod (env, codec->object,
       media_codec.get_output_format);
   if ((*env)->ExceptionCheck (env)) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_SETTINGS, err,
-        "Failed to get output format");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_SETTINGS,
+        err, "Failed to get output format");
     goto done;
   }
 
@@ -657,8 +220,8 @@ gst_amc_codec_get_output_format (GstAmcCodec * codec, GError ** err)
 
   ret->object = (*env)->NewGlobalRef (env, object);
   if (!ret->object) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_SETTINGS, err,
-        "Failed to create global format reference");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_SETTINGS,
+        err, "Failed to create global format reference");
     g_slice_free (GstAmcFormat, ret);
     ret = NULL;
   }
@@ -678,12 +241,12 @@ gst_amc_codec_start (GstAmcCodec * codec, GError ** err)
 
   g_return_val_if_fail (codec != NULL, FALSE);
 
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   (*env)->CallVoidMethod (env, codec->object, media_codec.start);
   if ((*env)->ExceptionCheck (env)) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to start codec");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to start codec");
     ret = FALSE;
     goto done;
   }
@@ -701,12 +264,12 @@ gst_amc_codec_stop (GstAmcCodec * codec, GError ** err)
 
   g_return_val_if_fail (codec != NULL, FALSE);
 
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   (*env)->CallVoidMethod (env, codec->object, media_codec.stop);
   if ((*env)->ExceptionCheck (env)) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to stop codec");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to stop codec");
     ret = FALSE;
     goto done;
   }
@@ -724,12 +287,12 @@ gst_amc_codec_flush (GstAmcCodec * codec, GError ** err)
 
   g_return_val_if_fail (codec != NULL, FALSE);
 
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   (*env)->CallVoidMethod (env, codec->object, media_codec.flush);
   if ((*env)->ExceptionCheck (env)) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to flush codec");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to flush codec");
     ret = FALSE;
     goto done;
   }
@@ -747,12 +310,12 @@ gst_amc_codec_release (GstAmcCodec * codec, GError ** err)
 
   g_return_val_if_fail (codec != NULL, FALSE);
 
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   (*env)->CallVoidMethod (env, codec->object, media_codec.release);
   if ((*env)->ExceptionCheck (env)) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to release codec");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to release codec");
     ret = FALSE;
     goto done;
   }
@@ -770,7 +333,7 @@ gst_amc_codec_free_buffers (GstAmcBuffer * buffers, gsize n_buffers)
 
   g_return_if_fail (buffers != NULL);
 
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   for (i = 0; i < n_buffers; i++) {
     if (buffers[i].object)
@@ -793,21 +356,21 @@ gst_amc_codec_get_output_buffers (GstAmcCodec * codec, gsize * n_buffers,
   g_return_val_if_fail (n_buffers != NULL, NULL);
 
   *n_buffers = 0;
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   output_buffers =
       (*env)->CallObjectMethod (env, codec->object,
       media_codec.get_output_buffers);
   if ((*env)->ExceptionCheck (env) || !output_buffers) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to get output buffers");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to get output buffers");
     goto done;
   }
 
   n_output_buffers = (*env)->GetArrayLength (env, output_buffers);
   if ((*env)->ExceptionCheck (env)) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to get output buffers array length");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to get output buffers array length");
     goto done;
   }
 
@@ -819,23 +382,23 @@ gst_amc_codec_get_output_buffers (GstAmcCodec * codec, gsize * n_buffers,
 
     buffer = (*env)->GetObjectArrayElement (env, output_buffers, i);
     if ((*env)->ExceptionCheck (env) || !buffer) {
-      gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-          "Failed to get output buffer %d", i);
+      gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+          err, "Failed to get output buffer %d", i);
       goto error;
     }
 
     ret[i].object = (*env)->NewGlobalRef (env, buffer);
     (*env)->DeleteLocalRef (env, buffer);
     if (!ret[i].object) {
-      gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-          "Failed to create global output buffer reference %d", i);
+      gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+          err, "Failed to create global output buffer reference %d", i);
       goto error;
     }
 
     ret[i].data = (*env)->GetDirectBufferAddress (env, ret[i].object);
     if (!ret[i].data) {
-      gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-          "Failed to get output buffer address %d", i);
+      gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+          err, "Failed to get output buffer address %d", i);
       goto error;
     }
     ret[i].size = (*env)->GetDirectBufferCapacity (env, ret[i].object);
@@ -869,21 +432,21 @@ gst_amc_codec_get_input_buffers (GstAmcCodec * codec, gsize * n_buffers,
   g_return_val_if_fail (n_buffers != NULL, NULL);
 
   *n_buffers = 0;
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   input_buffers =
       (*env)->CallObjectMethod (env, codec->object,
       media_codec.get_input_buffers);
   if ((*env)->ExceptionCheck (env) || !input_buffers) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to get input buffers");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to get input buffers");
     goto done;
   }
 
   n_input_buffers = (*env)->GetArrayLength (env, input_buffers);
   if ((*env)->ExceptionCheck (env)) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to get input buffers array length");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to get input buffers array length");
     goto done;
   }
 
@@ -895,23 +458,23 @@ gst_amc_codec_get_input_buffers (GstAmcCodec * codec, gsize * n_buffers,
 
     buffer = (*env)->GetObjectArrayElement (env, input_buffers, i);
     if ((*env)->ExceptionCheck (env) || !buffer) {
-      gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-          "Failed to get input buffer %d", i);
+      gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+          err, "Failed to get input buffer %d", i);
       goto error;
     }
 
     ret[i].object = (*env)->NewGlobalRef (env, buffer);
     (*env)->DeleteLocalRef (env, buffer);
     if (!ret[i].object) {
-      gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-          "Failed to create global input buffer reference %d", i);
+      gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+          err, "Failed to create global input buffer reference %d", i);
       goto error;
     }
 
     ret[i].data = (*env)->GetDirectBufferAddress (env, ret[i].object);
     if (!ret[i].data) {
-      gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-          "Failed to get input buffer address %d", i);
+      gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+          err, "Failed to get input buffer address %d", i);
       goto error;
     }
     ret[i].size = (*env)->GetDirectBufferCapacity (env, ret[i].object);
@@ -940,14 +503,14 @@ gst_amc_codec_dequeue_input_buffer (GstAmcCodec * codec, gint64 timeoutUs,
 
   g_return_val_if_fail (codec != NULL, G_MININT);
 
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   ret =
       (*env)->CallIntMethod (env, codec->object,
       media_codec.dequeue_input_buffer, timeoutUs);
   if ((*env)->ExceptionCheck (env)) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to dequeue input buffer");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to dequeue input buffer");
     ret = G_MININT;
     goto done;
   }
@@ -966,16 +529,16 @@ gst_amc_codec_fill_buffer_info (JNIEnv * env, jobject buffer_info,
   info->flags =
       (*env)->GetIntField (env, buffer_info, media_codec_buffer_info.flags);
   if ((*env)->ExceptionCheck (env)) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to get buffer info flags");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to get buffer info flags");
     return FALSE;
   }
 
   info->offset =
       (*env)->GetIntField (env, buffer_info, media_codec_buffer_info.offset);
   if ((*env)->ExceptionCheck (env)) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to get buffer info offset");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to get buffer info offset");
     return FALSE;
   }
 
@@ -983,8 +546,8 @@ gst_amc_codec_fill_buffer_info (JNIEnv * env, jobject buffer_info,
       (*env)->GetLongField (env, buffer_info,
       media_codec_buffer_info.presentation_time_us);
   if ((*env)->ExceptionCheck (env)) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to get buffer info pts");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to get buffer info pts");
     return FALSE;
   }
 
@@ -992,8 +555,8 @@ gst_amc_codec_fill_buffer_info (JNIEnv * env, jobject buffer_info,
       (*env)->GetIntField (env, buffer_info, media_codec_buffer_info.size);
   if ((*env)->ExceptionCheck (env)) {
     (*env)->ExceptionClear (env);
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to get buffer info size");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to get buffer info size");
     return FALSE;
   }
 
@@ -1010,14 +573,14 @@ gst_amc_codec_dequeue_output_buffer (GstAmcCodec * codec,
 
   g_return_val_if_fail (codec != NULL, G_MININT);
 
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   info_o =
       (*env)->NewObject (env, media_codec_buffer_info.klass,
       media_codec_buffer_info.constructor);
   if (!info_o) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to create buffer info instance");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to create buffer info instance");
     goto done;
   }
 
@@ -1025,8 +588,8 @@ gst_amc_codec_dequeue_output_buffer (GstAmcCodec * codec,
       (*env)->CallIntMethod (env, codec->object,
       media_codec.dequeue_output_buffer, info_o, timeoutUs);
   if ((*env)->ExceptionCheck (env)) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to dequeue output buffer");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to dequeue output buffer");
     ret = G_MININT;
     goto done;
   }
@@ -1054,13 +617,13 @@ gst_amc_codec_queue_input_buffer (GstAmcCodec * codec, gint index,
   g_return_val_if_fail (codec != NULL, FALSE);
   g_return_val_if_fail (info != NULL, FALSE);
 
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   (*env)->CallVoidMethod (env, codec->object, media_codec.queue_input_buffer,
       index, info->offset, info->size, info->presentation_time_us, info->flags);
   if ((*env)->ExceptionCheck (env)) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to queue input buffer");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to queue input buffer");
     ret = FALSE;
     goto done;
   }
@@ -1079,13 +642,13 @@ gst_amc_codec_release_output_buffer (GstAmcCodec * codec, gint index,
 
   g_return_val_if_fail (codec != NULL, FALSE);
 
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   (*env)->CallVoidMethod (env, codec->object, media_codec.release_output_buffer,
       index, JNI_FALSE);
   if ((*env)->ExceptionCheck (env)) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to release output buffer");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to release output buffer");
     ret = FALSE;
     goto done;
   }
@@ -1106,11 +669,11 @@ gst_amc_format_new_audio (const gchar * mime, gint sample_rate, gint channels,
 
   g_return_val_if_fail (mime != NULL, NULL);
 
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   mime_str = (*env)->NewStringUTF (env, mime);
   if (mime_str == NULL) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_INIT, err,
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_INIT, err,
         "Failed to create Java string");
     goto error;
   }
@@ -1121,14 +684,14 @@ gst_amc_format_new_audio (const gchar * mime, gint sample_rate, gint channels,
       (*env)->CallStaticObjectMethod (env, media_format.klass,
       media_format.create_audio_format, mime_str, sample_rate, channels);
   if ((*env)->ExceptionCheck (env) || !object) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_INIT, err,
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_INIT, err,
         "Failed to create format instance '%s'", mime);
     goto error;
   }
 
   format->object = (*env)->NewGlobalRef (env, object);
   if (!format->object) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_INIT, err,
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_INIT, err,
         "Failed to create global format reference");
     goto error;
   }
@@ -1160,11 +723,11 @@ gst_amc_format_new_video (const gchar * mime, gint width, gint height,
 
   g_return_val_if_fail (mime != NULL, NULL);
 
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   mime_str = (*env)->NewStringUTF (env, mime);
   if (mime_str == NULL) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_INIT, err,
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_INIT, err,
         "Failed to create Java string");
     goto error;
   }
@@ -1175,14 +738,14 @@ gst_amc_format_new_video (const gchar * mime, gint width, gint height,
       (*env)->CallStaticObjectMethod (env, media_format.klass,
       media_format.create_video_format, mime_str, width, height);
   if ((*env)->ExceptionCheck (env) || !object) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_INIT, err,
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_INIT, err,
         "Failed to create format instance '%s'", mime);
     goto error;
   }
 
   format->object = (*env)->NewGlobalRef (env, object);
   if (!format->object) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_INIT, err,
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_INIT, err,
         "Failed to create global format reference");
     goto error;
   }
@@ -1210,7 +773,7 @@ gst_amc_format_free (GstAmcFormat * format)
 
   g_return_if_fail (format != NULL);
 
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
   (*env)->DeleteGlobalRef (env, format->object);
   g_slice_free (GstAmcFormat, format);
 }
@@ -1225,20 +788,20 @@ gst_amc_format_to_string (GstAmcFormat * format, GError ** err)
 
   g_return_val_if_fail (format != NULL, FALSE);
 
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   v_str =
       (*env)->CallObjectMethod (env, format->object, media_format.to_string);
   if ((*env)->ExceptionCheck (env)) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to convert format to string");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to convert format to string");
     goto done;
   }
 
   v = (*env)->GetStringUTFChars (env, v_str, NULL);
   if (!v) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to get UTF8 string");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to get UTF8 string");
     goto done;
   }
 
@@ -1264,12 +827,12 @@ gst_amc_format_contains_key (GstAmcFormat * format, const gchar * key,
   g_return_val_if_fail (format != NULL, FALSE);
   g_return_val_if_fail (key != NULL, FALSE);
 
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   key_str = (*env)->NewStringUTF (env, key);
   if (!key_str) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to create Java string");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to create Java string");
     goto done;
   }
 
@@ -1277,8 +840,8 @@ gst_amc_format_contains_key (GstAmcFormat * format, const gchar * key,
       (*env)->CallBooleanMethod (env, format->object, media_format.contains_key,
       key_str);
   if ((*env)->ExceptionCheck (env)) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to check if format contains key '%s'", key);
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to check if format contains key '%s'", key);
     goto done;
   }
 
@@ -1302,12 +865,12 @@ gst_amc_format_get_float (GstAmcFormat * format, const gchar * key,
   g_return_val_if_fail (value != NULL, FALSE);
 
   *value = 0;
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   key_str = (*env)->NewStringUTF (env, key);
   if (!key_str) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to create Java string");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to create Java string");
     goto done;
   }
 
@@ -1315,8 +878,8 @@ gst_amc_format_get_float (GstAmcFormat * format, const gchar * key,
       (*env)->CallFloatMethod (env, format->object, media_format.get_float,
       key_str);
   if ((*env)->ExceptionCheck (env)) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed get float key '%s'", key);
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed get float key '%s'", key);
     goto done;
   }
   ret = TRUE;
@@ -1338,20 +901,20 @@ gst_amc_format_set_float (GstAmcFormat * format, const gchar * key,
   g_return_if_fail (format != NULL);
   g_return_if_fail (key != NULL);
 
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   key_str = (*env)->NewStringUTF (env, key);
   if (!key_str) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to create Java string");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to create Java string");
     goto done;
   }
 
   (*env)->CallVoidMethod (env, format->object, media_format.set_float, key_str,
       value);
   if ((*env)->ExceptionCheck (env)) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed set float key '%s'", key);
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed set float key '%s'", key);
     goto done;
   }
 
@@ -1373,12 +936,12 @@ gst_amc_format_get_int (GstAmcFormat * format, const gchar * key, gint * value,
   g_return_val_if_fail (value != NULL, FALSE);
 
   *value = 0;
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   key_str = (*env)->NewStringUTF (env, key);
   if (!key_str) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to create Java string");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to create Java string");
     goto done;
   }
 
@@ -1386,8 +949,8 @@ gst_amc_format_get_int (GstAmcFormat * format, const gchar * key, gint * value,
       (*env)->CallIntMethod (env, format->object, media_format.get_integer,
       key_str);
   if ((*env)->ExceptionCheck (env)) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed get integer key '%s'", key);
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed get integer key '%s'", key);
     goto done;
   }
   ret = TRUE;
@@ -1410,20 +973,20 @@ gst_amc_format_set_int (GstAmcFormat * format, const gchar * key, gint value,
   g_return_if_fail (format != NULL);
   g_return_if_fail (key != NULL);
 
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   key_str = (*env)->NewStringUTF (env, key);
   if (!key_str) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to create Java string");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to create Java string");
     goto done;
   }
 
   (*env)->CallVoidMethod (env, format->object, media_format.set_integer,
       key_str, value);
   if ((*env)->ExceptionCheck (env)) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed set integer key '%s'", key);
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed set integer key '%s'", key);
     goto done;
   }
 
@@ -1447,12 +1010,12 @@ gst_amc_format_get_string (GstAmcFormat * format, const gchar * key,
   g_return_val_if_fail (value != NULL, FALSE);
 
   *value = 0;
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   key_str = (*env)->NewStringUTF (env, key);
   if (!key_str) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to create Java string");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to create Java string");
     goto done;
   }
 
@@ -1460,15 +1023,15 @@ gst_amc_format_get_string (GstAmcFormat * format, const gchar * key,
       (*env)->CallObjectMethod (env, format->object, media_format.get_string,
       key_str);
   if ((*env)->ExceptionCheck (env)) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed get string key '%s'", key);
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed get string key '%s'", key);
     goto done;
   }
 
   v = (*env)->GetStringUTFChars (env, v_str, NULL);
   if (!v) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed get string UTF8 characters");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed get string UTF8 characters");
     goto done;
   }
 
@@ -1499,27 +1062,27 @@ gst_amc_format_set_string (GstAmcFormat * format, const gchar * key,
   g_return_if_fail (key != NULL);
   g_return_if_fail (value != NULL);
 
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   key_str = (*env)->NewStringUTF (env, key);
   if (!key_str) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to create Java string");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to create Java string");
     goto done;
   }
 
   v_str = (*env)->NewStringUTF (env, value);
   if (!v_str) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to create Java string");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to create Java string");
     goto done;
   }
 
   (*env)->CallVoidMethod (env, format->object, media_format.set_string, key_str,
       v_str);
   if ((*env)->ExceptionCheck (env)) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed set string key '%s'", key);
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed set string key '%s'", key);
     goto done;
   }
 
@@ -1546,27 +1109,27 @@ gst_amc_format_get_buffer (GstAmcFormat * format, const gchar * key,
 
   *data = NULL;
   *size = 0;
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   key_str = (*env)->NewStringUTF (env, key);
   if (!key_str) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to create Java string");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to create Java string");
     goto done;
   }
 
   v = (*env)->CallObjectMethod (env, format->object,
       media_format.get_byte_buffer, key_str);
   if ((*env)->ExceptionCheck (env)) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed get buffer key '%s'", key);
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed get buffer key '%s'", key);
     goto done;
   }
 
   *data = (*env)->GetDirectBufferAddress (env, v);
   if (!data) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed get buffer address");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed get buffer address");
     goto done;
   }
   *size = (*env)->GetDirectBufferCapacity (env, v);
@@ -1595,28 +1158,28 @@ gst_amc_format_set_buffer (GstAmcFormat * format, const gchar * key,
   g_return_if_fail (key != NULL);
   g_return_if_fail (data != NULL);
 
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   key_str = (*env)->NewStringUTF (env, key);
   if (!key_str) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed to create Java string");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed to create Java string");
     goto done;
   }
 
   /* FIXME: The memory must remain valid until the codec is stopped */
   v = (*env)->NewDirectByteBuffer (env, data, size);
   if (!v) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed create Java byte buffer");
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed create Java byte buffer");
     goto done;
   }
 
   (*env)->CallVoidMethod (env, format->object, media_format.set_byte_buffer,
       key_str, v);
   if ((*env)->ExceptionCheck (env)) {
-    gst_amc_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED, err,
-        "Failed set buffer key '%s'", key);
+    gst_amc_jni_set_error (env, GST_LIBRARY_ERROR, GST_LIBRARY_ERROR_FAILED,
+        err, "Failed set buffer key '%s'", key);
     goto done;
   }
 
@@ -1636,7 +1199,7 @@ get_java_classes (void)
 
   GST_DEBUG ("Retrieving Java classes");
 
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   tmp = (*env)->FindClass (env, "java/lang/String");
   if (!tmp) {
@@ -1968,7 +1531,7 @@ scan_codecs (GstPlugin * plugin)
     return TRUE;
   }
 
-  env = gst_amc_get_jni_env ();
+  env = gst_amc_jni_get_env ();
 
   codec_list_class = (*env)->FindClass (env, "android/media/MediaCodecList");
   if (!codec_list_class) {
@@ -2108,7 +1671,8 @@ scan_codecs (GstPlugin * plugin)
      * VM via the non-public AndroidRuntime class. Can we somehow
      * initialize all this?
      */
-    if (started_java_vm && !g_str_has_prefix (name_str, "OMX.google.")) {
+    if (gst_amc_jni_is_vm_started () &&
+        !g_str_has_prefix (name_str, "OMX.google.")) {
       GST_INFO ("Skipping non-Google codec '%s' in standalone mode", name_str);
       valid_codec = FALSE;
       goto next_codec;
@@ -3709,9 +3273,7 @@ plugin_init (GstPlugin * plugin)
 
   GST_DEBUG_CATEGORY_INIT (gst_amc_debug, "amc", 0, "android-media-codec");
 
-  pthread_key_create (&current_jni_env, gst_amc_detach_current_thread);
-
-  if (!initialize_java_vm ())
+  if (!gst_amc_jni_initialize ())
     return FALSE;
 
   gst_plugin_add_dependency_simple (plugin, NULL, "/etc", "media_codecs.xml",
diff --git a/sys/androidmedia/gstjniutils.c b/sys/androidmedia/gstjniutils.c
new file mode 100644
index 000000000..9d8a4777f
--- /dev/null
+++ b/sys/androidmedia/gstjniutils.c
@@ -0,0 +1,484 @@
+/*
+ * Copyright (C) 2012, Collabora Ltd.
+ *   Author: Sebastian Dröge <sebastian.droege@collabora.co.uk>
+ * Copyright (C) 2013, Fluendo S.A.
+ *   Author: Andoni Morales <amorales@fluendo.com>
+ * Copyright (C) 2014, Sebastian Dröge <sebastian@centricular.com>
+ * Copyright (C) 2014, Collabora Ltd.
+ *   Author: Matthieu Bouron <matthieu.bouron@collabora.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation
+ * version 2.1 of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gst/gst.h>
+#include <pthread.h>
+#include <gmodule.h>
+
+#include "gstjniutils.h"
+
+static GModule *java_module;
+static jint (*get_created_java_vms) (JavaVM ** vmBuf, jsize bufLen,
+    jsize * nVMs);
+static jint (*create_java_vm) (JavaVM ** p_vm, JNIEnv ** p_env, void *vm_args);
+static JavaVM *java_vm;
+static gboolean initialized = FALSE;
+static gboolean started_java_vm = FALSE;
+static pthread_key_t current_jni_env;
+
+/* getExceptionSummary() and getStackTrace() taken from Android's
+ *   platform/libnativehelper/JNIHelp.cpp
+ * Modified to work with normal C strings and without C++.
+ *
+ * Copyright (C) 2006 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * Returns a human-readable summary of an exception object. The buffer will
+ * be populated with the "binary" class name and, if present, the
+ * exception message.
+ */
+static gchar *
+getExceptionSummary (JNIEnv * env, jthrowable exception)
+{
+  GString *gs = g_string_new ("");
+  jclass exceptionClass = NULL, classClass = NULL;
+  jmethodID classGetNameMethod, getMessage;
+  jstring classNameStr = NULL, messageStr = NULL;
+  const char *classNameChars, *messageChars;
+
+  /* get the name of the exception's class */
+  exceptionClass = (*env)->GetObjectClass (env, exception);
+  classClass = (*env)->GetObjectClass (env, exceptionClass);
+  classGetNameMethod =
+      (*env)->GetMethodID (env, classClass, "getName", "()Ljava/lang/String;");
+
+  classNameStr =
+      (jstring) (*env)->CallObjectMethod (env, exceptionClass,
+      classGetNameMethod);
+
+  if (classNameStr == NULL) {
+    if ((*env)->ExceptionCheck (env))
+      (*env)->ExceptionClear (env);
+    g_string_append (gs, "<error getting class name>");
+    goto done;
+  }
+
+  classNameChars = (*env)->GetStringUTFChars (env, classNameStr, NULL);
+  if (classNameChars == NULL) {
+    if ((*env)->ExceptionCheck (env))
+      (*env)->ExceptionClear (env);
+    g_string_append (gs, "<error getting class name UTF-8>");
+    goto done;
+  }
+
+  g_string_append (gs, classNameChars);
+
+  (*env)->ReleaseStringUTFChars (env, classNameStr, classNameChars);
+
+  /* if the exception has a detail message, get that */
+  getMessage =
+      (*env)->GetMethodID (env, exceptionClass, "getMessage",
+      "()Ljava/lang/String;");
+  messageStr = (jstring) (*env)->CallObjectMethod (env, exception, getMessage);
+  if (messageStr == NULL) {
+    if ((*env)->ExceptionCheck (env))
+      (*env)->ExceptionClear (env);
+    goto done;
+  }
+  g_string_append (gs, ": ");
+
+  messageChars = (*env)->GetStringUTFChars (env, messageStr, NULL);
+  if (messageChars != NULL) {
+    g_string_append (gs, messageChars);
+    (*env)->ReleaseStringUTFChars (env, messageStr, messageChars);
+  } else {
+    if ((*env)->ExceptionCheck (env))
+      (*env)->ExceptionClear (env);
+    g_string_append (gs, "<error getting message>");
+  }
+
+done:
+  if (exceptionClass)
+    (*env)->DeleteLocalRef (env, exceptionClass);
+  if (classClass)
+    (*env)->DeleteLocalRef (env, classClass);
+  if (classNameStr)
+    (*env)->DeleteLocalRef (env, classNameStr);
+  if (messageStr)
+    (*env)->DeleteLocalRef (env, messageStr);
+
+  return g_string_free (gs, FALSE);
+}
+
+/*
+ * Returns an exception (with stack trace) as a string.
+ */
+static gchar *
+getStackTrace (JNIEnv * env, jthrowable exception)
+{
+  GString *gs = g_string_new ("");
+  jclass stringWriterClass = NULL, printWriterClass = NULL;
+  jclass exceptionClass = NULL;
+  jmethodID stringWriterCtor, stringWriterToStringMethod;
+  jmethodID printWriterCtor, printStackTraceMethod;
+  jobject stringWriter = NULL, printWriter = NULL;
+  jstring messageStr = NULL;
+  const char *utfChars;
+
+  stringWriterClass = (*env)->FindClass (env, "java/io/StringWriter");
+
+  if (stringWriterClass == NULL) {
+    g_string_append (gs, "<error getting java.io.StringWriter class>");
+    goto done;
+  }
+
+  stringWriterCtor =
+      (*env)->GetMethodID (env, stringWriterClass, "<init>", "()V");
+  stringWriterToStringMethod =
+      (*env)->GetMethodID (env, stringWriterClass, "toString",
+      "()Ljava/lang/String;");
+
+  printWriterClass = (*env)->FindClass (env, "java/io/PrintWriter");
+  if (printWriterClass == NULL) {
+    g_string_append (gs, "<error getting java.io.PrintWriter class>");
+    goto done;
+  }
+
+  printWriterCtor =
+      (*env)->GetMethodID (env, printWriterClass, "<init>",
+      "(Ljava/io/Writer;)V");
+  stringWriter = (*env)->NewObject (env, stringWriterClass, stringWriterCtor);
+  if (stringWriter == NULL) {
+    if ((*env)->ExceptionCheck (env))
+      (*env)->ExceptionClear (env);
+    g_string_append (gs, "<error creating new StringWriter instance>");
+    goto done;
+  }
+
+  printWriter =
+      (*env)->NewObject (env, printWriterClass, printWriterCtor, stringWriter);
+  if (printWriter == NULL) {
+    if ((*env)->ExceptionCheck (env))
+      (*env)->ExceptionClear (env);
+    g_string_append (gs, "<error creating new PrintWriter instance>");
+    goto done;
+  }
+
+  exceptionClass = (*env)->GetObjectClass (env, exception);
+  printStackTraceMethod =
+      (*env)->GetMethodID (env, exceptionClass, "printStackTrace",
+      "(Ljava/io/PrintWriter;)V");
+  (*env)->CallVoidMethod (env, exception, printStackTraceMethod, printWriter);
+  if ((*env)->ExceptionCheck (env)) {
+    (*env)->ExceptionClear (env);
+    g_string_append (gs, "<exception while printing stack trace>");
+    goto done;
+  }
+
+  messageStr = (jstring) (*env)->CallObjectMethod (env, stringWriter,
+      stringWriterToStringMethod);
+  if (messageStr == NULL) {
+    if ((*env)->ExceptionCheck (env))
+      (*env)->ExceptionClear (env);
+    g_string_append (gs, "<failed to call StringWriter.toString()>");
+    goto done;
+  }
+
+  utfChars = (*env)->GetStringUTFChars (env, messageStr, NULL);
+  if (utfChars == NULL) {
+    if ((*env)->ExceptionCheck (env))
+      (*env)->ExceptionClear (env);
+    g_string_append (gs, "<failed to get UTF chars for message>");
+    goto done;
+  }
+
+  g_string_append (gs, utfChars);
+
+  (*env)->ReleaseStringUTFChars (env, messageStr, utfChars);
+
+done:
+  if (stringWriterClass)
+    (*env)->DeleteLocalRef (env, stringWriterClass);
+  if (printWriterClass)
+    (*env)->DeleteLocalRef (env, printWriterClass);
+  if (exceptionClass)
+    (*env)->DeleteLocalRef (env, exceptionClass);
+  if (stringWriter)
+    (*env)->DeleteLocalRef (env, stringWriter);
+  if (printWriter)
+    (*env)->DeleteLocalRef (env, printWriter);
+  if (messageStr)
+    (*env)->DeleteLocalRef (env, messageStr);
+
+  return g_string_free (gs, FALSE);
+}
+
+static JNIEnv *
+gst_amc_jni_attach_current_thread (void)
+{
+  JNIEnv *env;
+  JavaVMAttachArgs args;
+
+  GST_DEBUG ("Attaching thread %p", g_thread_self ());
+  args.version = JNI_VERSION_1_6;
+  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;
+}
+
+static void
+gst_amc_jni_detach_current_thread (void *env)
+{
+  GST_DEBUG ("Detaching thread %p", g_thread_self ());
+  (*java_vm)->DetachCurrentThread (java_vm);
+}
+
+static gboolean
+check_nativehelper (void)
+{
+  GModule *module;
+  void **jni_invocation = NULL;
+  gboolean ret = FALSE;
+
+  module = g_module_open (NULL, G_MODULE_BIND_LOCAL);
+  if (!module)
+    return ret;
+
+  /* Check if libnativehelper is loaded in the process and if
+   * it has these awful wrappers for JNI_CreateJavaVM and
+   * JNI_GetCreatedJavaVMs that crash the app if you don't
+   * create a JniInvocation instance first. If it isn't we
+   * just fail here and don't initialize anything.
+   * See this code for reference:
+   * https://android.googlesource.com/platform/libnativehelper/+/master/JniInvocation.cpp
+   */
+  if (!g_module_symbol (module, "_ZN13JniInvocation15jni_invocation_E",
+          (gpointer *) & jni_invocation)) {
+    ret = TRUE;
+  } else {
+    ret = (jni_invocation != NULL && *jni_invocation != NULL);
+  }
+
+  g_module_close (module);
+
+  return ret;
+}
+
+static gboolean
+load_java_module (const gchar * name)
+{
+  java_module = g_module_open (name, G_MODULE_BIND_LOCAL);
+  if (!java_module)
+    goto load_failed;
+
+  if (!g_module_symbol (java_module, "JNI_CreateJavaVM",
+          (gpointer *) & create_java_vm))
+    goto symbol_error;
+
+  if (!g_module_symbol (java_module, "JNI_GetCreatedJavaVMs",
+          (gpointer *) & get_created_java_vms))
+    goto symbol_error;
+
+  return TRUE;
+
+load_failed:
+  {
+    GST_ERROR ("Failed to load Java module '%s': %s", GST_STR_NULL (name),
+        g_module_error ());
+    return FALSE;
+  }
+symbol_error:
+  {
+    GST_ERROR ("Failed to locate required JNI symbols in '%s': %s",
+        GST_STR_NULL (name), g_module_error ());
+    g_module_close (java_module);
+    java_module = NULL;
+    return FALSE;
+  }
+}
+
+static gboolean
+gst_amc_jni_initialize_java_vm (void)
+{
+  jsize n_vms;
+
+  /* Returns TRUE if we can safely
+   * a) get the current VMs and
+   * b) start a VM if none is started yet
+   *
+   * FIXME: On Android >= 4.4 we won't be able to safely start a
+   * VM on our own without using private C++ API!
+   */
+  if (!check_nativehelper ()) {
+    GST_ERROR ("Can't safely check for VMs or start a VM");
+    return FALSE;
+  }
+
+  if (!load_java_module (NULL)) {
+    if (!load_java_module ("libdvm"))
+      return FALSE;
+  }
+
+  n_vms = 0;
+  if (get_created_java_vms (&java_vm, 1, &n_vms) < 0)
+    goto get_created_failed;
+
+  if (n_vms > 0) {
+    GST_DEBUG ("Successfully got existing Java VM %p", java_vm);
+  } else {
+    JNIEnv *env;
+    JavaVMInitArgs vm_args;
+    JavaVMOption options[4];
+
+    GST_DEBUG ("Found no existing Java VM, trying to start one");
+
+    options[0].optionString = "-verbose:jni";
+    options[1].optionString = "-verbose:gc";
+    options[2].optionString = "-Xcheck:jni";
+    options[3].optionString = "-Xdebug";
+
+    vm_args.version = JNI_VERSION_1_4;
+    vm_args.options = options;
+    vm_args.nOptions = 4;
+    vm_args.ignoreUnrecognized = JNI_TRUE;
+    if (create_java_vm (&java_vm, &env, &vm_args) < 0)
+      goto create_failed;
+    GST_DEBUG ("Successfully created Java VM %p", java_vm);
+
+    started_java_vm = TRUE;
+  }
+
+  return java_vm != NULL;
+
+get_created_failed:
+  {
+    GST_ERROR ("Failed to get already created VMs");
+    g_module_close (java_module);
+    java_module = NULL;
+    return FALSE;
+  }
+create_failed:
+  {
+    GST_ERROR ("Failed to create a Java VM");
+    g_module_close (java_module);
+    java_module = NULL;
+    return FALSE;
+  }
+}
+
+static void
+gst_amc_jni_set_error_string (JNIEnv * env, GQuark domain, gint code,
+    GError ** err, const gchar * message)
+{
+  jthrowable exception;
+
+  if (!err) {
+    if ((*env)->ExceptionCheck (env))
+      (*env)->ExceptionClear (env);
+    return;
+  }
+
+  if ((*env)->ExceptionCheck (env)) {
+    if ((exception = (*env)->ExceptionOccurred (env))) {
+      gchar *exception_description, *exception_stacktrace;
+
+      /* Clear exception so that we can call Java methods again */
+      (*env)->ExceptionClear (env);
+
+      exception_description = getExceptionSummary (env, exception);
+      exception_stacktrace = getStackTrace (env, exception);
+      g_set_error (err, domain, code, "%s: %s\n%s", message,
+          exception_description, exception_stacktrace);
+      g_free (exception_description);
+      g_free (exception_stacktrace);
+
+      (*env)->DeleteLocalRef (env, exception);
+    } else {
+      (*env)->ExceptionClear (env);
+      g_set_error (err, domain, code, "%s", message);
+    }
+  } else {
+    g_set_error (err, domain, code, "%s", message);
+  }
+}
+
+G_GNUC_PRINTF (5, 6)
+     void gst_amc_jni_set_error (JNIEnv * env, GQuark domain, gint code,
+    GError ** err, const gchar * format, ...)
+{
+  gchar *message;
+  va_list var_args;
+
+  va_start (var_args, format);
+  message = g_strdup_vprintf (format, var_args);
+  va_end (var_args);
+
+  gst_amc_jni_set_error_string (env, domain, code, err, message);
+
+  g_free (message);
+}
+
+
+gboolean
+gst_amc_jni_initialize (void)
+{
+  if (!initialized) {
+    pthread_key_create (&current_jni_env, gst_amc_jni_detach_current_thread);
+    initialized = gst_amc_jni_initialize_java_vm ();
+  }
+  return initialized;
+}
+
+JNIEnv *
+gst_amc_jni_get_env (void)
+{
+  JNIEnv *env;
+
+  if ((env = pthread_getspecific (current_jni_env)) == NULL) {
+    env = gst_amc_jni_attach_current_thread ();
+    pthread_setspecific (current_jni_env, env);
+  }
+
+  return env;
+}
+
+gboolean
+gst_amc_jni_is_vm_started (void)
+{
+  return started_java_vm;
+}
diff --git a/sys/androidmedia/gstjniutils.h b/sys/androidmedia/gstjniutils.h
new file mode 100644
index 000000000..ad4e2f424
--- /dev/null
+++ b/sys/androidmedia/gstjniutils.h
@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2012, Collabora Ltd.
+ *   Author: Sebastian Dröge <sebastian.droege@collabora.co.uk>
+ * Copyright (C) 2013, Fluendo S.A.
+ *   Author: Andoni Morales <amorales@fluendo.com>
+ * Copyright (C) 2014, Sebastian Dröge <sebastian@centricular.com>
+ * Copyright (C) 2014, Collabora Ltd.
+ *   Author: Matthieu Bouron <matthieu.bouron@collabora.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation
+ * version 2.1 of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
+ *
+ */
+#ifndef __GST_AMC_JNI_UTILS_H__
+#define __GST_AMC_JNI_UTILS_H__
+
+#include <jni.h>
+#include <glib.h>
+#include <gst/gst.h>
+
+G_GNUC_PRINTF (5, 6)
+void gst_amc_jni_set_error                   (JNIEnv * env,
+                                              GQuark domain,
+                                              gint code,
+                                              GError ** error,
+                                              const gchar * format, ...);
+
+gboolean gst_amc_jni_initialize              (void);
+
+gboolean gst_amc_jni_is_vm_started           (void);
+
+JNIEnv *gst_amc_jni_get_env                  (void);
+
+#endif