diff --git a/media/ndk/NdkMediaFormatPriv.h b/include/media/NdkMediaFormatPriv.h
similarity index 79%
rename from media/ndk/NdkMediaFormatPriv.h
rename to include/media/NdkMediaFormatPriv.h
index c6a6563..6c452c3 100644
--- a/media/ndk/NdkMediaFormatPriv.h
+++ b/include/media/NdkMediaFormatPriv.h
@@ -27,13 +27,23 @@
 #ifndef _NDK_MEDIA_FORMAT_PRIV_H
 #define _NDK_MEDIA_FORMAT_PRIV_H
 
-#include <media/NdkMediaFormat.h>
+#include <utils/String8.h>
+#include <utils/StrongPointer.h>
+#include <media/stagefright/foundation/AMessage.h>
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-AMediaFormat* AMediaFormat_fromMsg(void*);
+using namespace android;
+
+struct AMediaFormat {
+    sp<AMessage> mFormat;
+    String8 mDebug;
+    KeyedVector<String8, String8> mStringCache;
+};
+
+AMediaFormat* AMediaFormat_fromMsg(const void*);
 void AMediaFormat_getFormat(const AMediaFormat* mData, void* dest);
 
 #ifdef __cplusplus
diff --git a/media/libmedia/Android.bp b/media/libmedia/Android.bp
index e6d6b3e..9fe9ee5 100644
--- a/media/libmedia/Android.bp
+++ b/media/libmedia/Android.bp
@@ -191,6 +191,7 @@
         "MediaResourcePolicy.cpp",
         "Visualizer.cpp",
         "StringArray.cpp",
+        "NdkMediaFormatPriv.cpp",
     ],
 
     aidl: {
diff --git a/media/libmedia/NdkMediaFormatPriv.cpp b/media/libmedia/NdkMediaFormatPriv.cpp
new file mode 100644
index 0000000..3c84d6a
--- /dev/null
+++ b/media/libmedia/NdkMediaFormatPriv.cpp
@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2018 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.
+ */
+
+//#define LOG_NDEBUG 0
+#define LOG_TAG "NdkMediaFormat"
+
+#include <inttypes.h>
+
+//#include <ndk/include/media/NdkMediaFormat.h>
+
+#include <utils/Log.h>
+#include <utils/StrongPointer.h>
+#include <media/NdkMediaFormatPriv.h>
+#include <media/stagefright/foundation/ABuffer.h>
+#include <media/stagefright/foundation/AMessage.h>
+//#include <android_runtime/AndroidRuntime.h>
+//#include <android_util_Binder.h>
+
+#include <jni.h>
+
+using namespace android;
+
+extern "C" {
+
+// private functions for conversion to/from AMessage
+AMediaFormat* AMediaFormat_fromMsg(const void* data) {
+    ALOGV("private ctor");
+    AMediaFormat* mData = new AMediaFormat();
+    mData->mFormat = *((sp<AMessage>*)data);
+    if (mData->mFormat == NULL) {
+        ALOGW("got NULL format");
+        mData->mFormat = new AMessage;
+    }
+    return mData;
+}
+
+void AMediaFormat_getFormat(const AMediaFormat* mData, void* dest) {
+    *((sp<AMessage>*)dest) = mData->mFormat;
+}
+
+} // extern "C"
+
+
diff --git a/media/ndk/NdkMediaCodec.cpp b/media/ndk/NdkMediaCodec.cpp
index 42285f8..c23f19b 100644
--- a/media/ndk/NdkMediaCodec.cpp
+++ b/media/ndk/NdkMediaCodec.cpp
@@ -21,8 +21,8 @@
 
 #include <media/NdkMediaCodec.h>
 #include <media/NdkMediaError.h>
+#include <media/NdkMediaFormatPriv.h>
 #include "NdkMediaCryptoPriv.h"
-#include "NdkMediaFormatPriv.h"
 
 #include <utils/Log.h>
 #include <utils/StrongPointer.h>
diff --git a/media/ndk/NdkMediaCrypto.cpp b/media/ndk/NdkMediaCrypto.cpp
index d7193ca..b8af5ff 100644
--- a/media/ndk/NdkMediaCrypto.cpp
+++ b/media/ndk/NdkMediaCrypto.cpp
@@ -20,7 +20,7 @@
 
 #include <media/NdkMediaCrypto.h>
 #include <media/NdkMediaCodec.h>
-#include "NdkMediaFormatPriv.h"
+#include <media/NdkMediaFormatPriv.h>
 
 
 #include <cutils/properties.h>
diff --git a/media/ndk/NdkMediaExtractor.cpp b/media/ndk/NdkMediaExtractor.cpp
index b5e60a4..8c1ac59 100644
--- a/media/ndk/NdkMediaExtractor.cpp
+++ b/media/ndk/NdkMediaExtractor.cpp
@@ -20,8 +20,8 @@
 
 #include <media/NdkMediaError.h>
 #include <media/NdkMediaExtractor.h>
+#include <media/NdkMediaFormatPriv.h>
 #include "NdkMediaDataSourcePriv.h"
-#include "NdkMediaFormatPriv.h"
 
 
 #include <inttypes.h>
diff --git a/media/ndk/NdkMediaFormat.cpp b/media/ndk/NdkMediaFormat.cpp
index f32b83e..a66f3b3 100644
--- a/media/ndk/NdkMediaFormat.cpp
+++ b/media/ndk/NdkMediaFormat.cpp
@@ -20,6 +20,7 @@
 #include <inttypes.h>
 
 #include <media/NdkMediaFormat.h>
+#include <media/NdkMediaFormatPriv.h>
 
 #include <utils/Log.h>
 #include <utils/StrongPointer.h>
@@ -32,12 +33,6 @@
 
 using namespace android;
 
-struct AMediaFormat {
-    sp<AMessage> mFormat;
-    String8 mDebug;
-    KeyedVector<String8, String8> mStringCache;
-};
-
 extern "C" {
 
 // private functions for conversion to/from AMessage
@@ -74,6 +69,18 @@
     return AMEDIA_OK;
 }
 
+EXPORT
+void AMediaFormat_clear(AMediaFormat *format) {
+    format->mFormat->clear();
+}
+
+EXPORT
+media_status_t AMediaFormat_copy(AMediaFormat *to, AMediaFormat *from) {
+    to->mFormat->clear();
+    to->mFormat->extend(from->mFormat);
+    return AMEDIA_OK;
+}
+
 
 EXPORT
 const char* AMediaFormat_toString(AMediaFormat *mData) {
@@ -256,7 +263,7 @@
 }
 
 EXPORT
-void AMediaFormat_setBuffer(AMediaFormat* format, const char* name, void* data, size_t size) {
+void AMediaFormat_setBuffer(AMediaFormat* format, const char* name, const void* data, size_t size) {
     // the ABuffer(void*, size_t) constructor doesn't take ownership of the data, so create
     // a new buffer and copy the data into it
     sp<ABuffer> buf = new ABuffer(size);
diff --git a/media/ndk/NdkMediaMuxer.cpp b/media/ndk/NdkMediaMuxer.cpp
index dffc4d7..b213fa9 100644
--- a/media/ndk/NdkMediaMuxer.cpp
+++ b/media/ndk/NdkMediaMuxer.cpp
@@ -20,7 +20,7 @@
 
 #include <media/NdkMediaMuxer.h>
 #include <media/NdkMediaCodec.h>
-#include "NdkMediaFormatPriv.h"
+#include <media/NdkMediaFormatPriv.h>
 
 
 #include <utils/Log.h>
diff --git a/media/ndk/include/media/NdkMediaFormat.h b/media/ndk/include/media/NdkMediaFormat.h
index 5f7804d..3f853d0 100644
--- a/media/ndk/include/media/NdkMediaFormat.h
+++ b/media/ndk/include/media/NdkMediaFormat.h
@@ -83,7 +83,7 @@
 /**
  * The provided data is copied into the format.
  */
-void AMediaFormat_setBuffer(AMediaFormat*, const char* name, void* data, size_t size) __INTRODUCED_IN(21);
+void AMediaFormat_setBuffer(AMediaFormat*, const char* name, const void* data, size_t size) __INTRODUCED_IN(21);
 
 
 
@@ -170,6 +170,18 @@
         int32_t left, int32_t top, int32_t right, int32_t bottom) __INTRODUCED_IN(28);
 #endif /* __ANDROID_API__ >= 28 */
 
+#if __ANDROID_API__ >= 29
+/**
+ * remove all key/value pairs from the given AMediaFormat
+ */
+void AMediaFormat_clear(AMediaFormat*) __INTRODUCED_IN(29);
+
+/**
+ * copy one AMediaFormat to another
+ */
+media_status_t AMediaFormat_copy(AMediaFormat *to, AMediaFormat *from) __INTRODUCED_IN(29);
+#endif /* __ANDROID_API__ >= 29 */
+
 __END_DECLS
 
 #endif // _NDK_MEDIA_FORMAT_H
diff --git a/media/ndk/libmediandk.map.txt b/media/ndk/libmediandk.map.txt
index d828d6a..0751a55 100644
--- a/media/ndk/libmediandk.map.txt
+++ b/media/ndk/libmediandk.map.txt
@@ -185,6 +185,8 @@
     AMediaExtractor_setDataSourceCustom; # introduced=28
     AMediaExtractor_setDataSourceFd;
     AMediaExtractor_unselectTrack;
+    AMediaFormat_clear; # introduced=29
+    AMediaFormat_copy; # introduced=29
     AMediaFormat_delete;
     AMediaFormat_getBuffer;
     AMediaFormat_getDouble; # introduced=28