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/*
* Copyright (C) 2013 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.
*/
package android.media;
import android.graphics.ImageFormat;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.util.Log;
import android.view.Surface;
import dalvik.system.VMRuntime;
import java.lang.ref.WeakReference;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.NioUtils;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.atomic.AtomicBoolean;
/**
* The ImageReader class allows direct application access to image data
* rendered into a {@link android.view.Surface}
*
* Several Android media API classes accept Surface objects as targets to
* render to, including {@link MediaPlayer}, {@link MediaCodec},
* {@link android.hardware.camera2.CameraDevice}, {@link ImageWriter} and
* {@link android.renderscript.Allocation RenderScript Allocations}. The image
* sizes and formats that can be used with each source vary, and should be
* checked in the documentation for the specific API.
*
* The image data is encapsulated in {@link Image} objects, and multiple such
* objects can be accessed at the same time, up to the number specified by the
* {@code maxImages} constructor parameter. New images sent to an ImageReader
* through its {@link Surface} are queued until accessed through the {@link #acquireLatestImage}
* or {@link #acquireNextImage} call. Due to memory limits, an image source will
* eventually stall or drop Images in trying to render to the Surface if the
* ImageReader does not obtain and release Images at a rate equal to the
* production rate.
*/
public class ImageReader implements AutoCloseable {
/**
* Returned by nativeImageSetup when acquiring the image was successful.
*/
private static final int ACQUIRE_SUCCESS = 0;
/**
* Returned by nativeImageSetup when we couldn't acquire the buffer,
* because there were no buffers available to acquire.
*/
private static final int ACQUIRE_NO_BUFS = 1;
/**
* Returned by nativeImageSetup when we couldn't acquire the buffer
* because the consumer has already acquired {@maxImages} and cannot
* acquire more than that.
*/
private static final int ACQUIRE_MAX_IMAGES = 2;
/**
*
* Create a new reader for images of the desired size and format.
*
*
* The {@code maxImages} parameter determines the maximum number of
* {@link Image} objects that can be be acquired from the
* {@code ImageReader} simultaneously. Requesting more buffers will use up
* more memory, so it is important to use only the minimum number necessary
* for the use case.
*
*
* The valid sizes and formats depend on the source of the image data.
*
*
* If the {@code format} is {@link ImageFormat#PRIVATE PRIVATE}, the created
* {@link ImageReader} will produce images that are not directly accessible
* by the application. The application can still acquire images from this
* {@link ImageReader}, and send them to the
* {@link android.hardware.camera2.CameraDevice camera} for reprocessing via
* {@link ImageWriter} interface. However, the {@link Image#getPlanes()
* getPlanes()} will return an empty array for {@link ImageFormat#PRIVATE
* PRIVATE} format images. The application can check if an existing reader's
* format by calling {@link #getImageFormat()}.
*
*
* {@link ImageFormat#PRIVATE PRIVATE} format {@link ImageReader
* ImageReaders} are more efficient to use when application access to image
* data is not necessary, compared to ImageReaders using other format such
* as {@link ImageFormat#YUV_420_888 YUV_420_888}.
*
*
* @param width The default width in pixels of the Images that this reader
* will produce.
* @param height The default height in pixels of the Images that this reader
* will produce.
* @param format The format of the Image that this reader will produce. This
* must be one of the {@link android.graphics.ImageFormat} or
* {@link android.graphics.PixelFormat} constants. Note that not
* all formats are supported, like ImageFormat.NV21.
* @param maxImages The maximum number of images the user will want to
* access simultaneously. This should be as small as possible to
* limit memory use. Once maxImages Images are obtained by the
* user, one of them has to be released before a new Image will
* become available for access through
* {@link #acquireLatestImage()} or {@link #acquireNextImage()}.
* Must be greater than 0.
* @see Image
*/
public static ImageReader newInstance(int width, int height, int format, int maxImages) {
return new ImageReader(width, height, format, maxImages);
}
/**
* @hide
*/
protected ImageReader(int width, int height, int format, int maxImages) {
mWidth = width;
mHeight = height;
mFormat = format;
mMaxImages = maxImages;
if (width < 1 || height < 1) {
throw new IllegalArgumentException(
"The image dimensions must be positive");
}
if (mMaxImages < 1) {
throw new IllegalArgumentException(
"Maximum outstanding image count must be at least 1");
}
if (format == ImageFormat.NV21) {
throw new IllegalArgumentException(
"NV21 format is not supported");
}
mNumPlanes = ImageUtils.getNumPlanesForFormat(mFormat);
nativeInit(new WeakReference(this), width, height, format, maxImages);
mSurface = nativeGetSurface();
mIsReaderValid = true;
// Estimate the native buffer allocation size and register it so it gets accounted for
// during GC. Note that this doesn't include the buffers required by the buffer queue
// itself and the buffers requested by the producer.
// Only include memory for 1 buffer, since actually accounting for the memory used is
// complex, and 1 buffer is enough for the VM to treat the ImageReader as being of some
// size.
mEstimatedNativeAllocBytes = ImageUtils.getEstimatedNativeAllocBytes(
width, height, format, /*buffer count*/ 1);
VMRuntime.getRuntime().registerNativeAllocation(mEstimatedNativeAllocBytes);
}
/**
* The default width of {@link Image Images}, in pixels.
*
* The width may be overridden by the producer sending buffers to this
* ImageReader's Surface. If so, the actual width of the images can be
* found using {@link Image#getWidth}.
*
* @return the expected width of an Image
*/
public int getWidth() {
return mWidth;
}
/**
* The default height of {@link Image Images}, in pixels.
*
* The height may be overridden by the producer sending buffers to this
* ImageReader's Surface. If so, the actual height of the images can be
* found using {@link Image#getHeight}.
*
* @return the expected height of an Image
*/
public int getHeight() {
return mHeight;
}
/**
* The default {@link ImageFormat image format} of {@link Image Images}.
*
* Some color formats may be overridden by the producer sending buffers to
* this ImageReader's Surface if the default color format allows. ImageReader
* guarantees that all {@link Image Images} acquired from ImageReader
* (for example, with {@link #acquireNextImage}) will have a "compatible"
* format to what was specified in {@link #newInstance}.
* As of now, each format is only compatible to itself.
* The actual format of the images can be found using {@link Image#getFormat}.
*
* @return the expected format of an Image
*
* @see ImageFormat
*/
public int getImageFormat() {
return mFormat;
}
/**
* Maximum number of images that can be acquired from the ImageReader by any time (for example,
* with {@link #acquireNextImage}).
*
* An image is considered acquired after it's returned by a function from ImageReader, and
* until the Image is {@link Image#close closed} to release the image back to the ImageReader.
*
*
* Attempting to acquire more than {@code maxImages} concurrently will result in the
* acquire function throwing a {@link IllegalStateException}. Furthermore,
* while the max number of images have been acquired by the ImageReader user, the producer
* enqueueing additional images may stall until at least one image has been released.
*
* @return Maximum number of images for this ImageReader.
*
* @see Image#close
*/
public int getMaxImages() {
return mMaxImages;
}
/**
* Get a {@link Surface} that can be used to produce {@link Image Images} for this
* {@code ImageReader}.
*
* Until valid image data is rendered into this {@link Surface}, the
* {@link #acquireNextImage} method will return {@code null}. Only one source
* can be producing data into this Surface at the same time, although the
* same {@link Surface} can be reused with a different API once the first source is
* disconnected from the {@link Surface}.
*
* @return A {@link Surface} to use for a drawing target for various APIs.
*/
public Surface getSurface() {
return mSurface;
}
/**
*
* Acquire the latest {@link Image} from the ImageReader's queue, dropping older
* {@link Image images}. Returns {@code null} if no new image is available.
*
*
* This operation will acquire all the images possible from the ImageReader,
* but {@link #close} all images that aren't the latest. This function is
* recommended to use over {@link #acquireNextImage} for most use-cases, as it's
* more suited for real-time processing.
*
*
* Note that {@link #getMaxImages maxImages} should be at least 2 for
* {@link #acquireLatestImage} to be any different than {@link #acquireNextImage} -
* discarding all-but-the-newest {@link Image} requires temporarily acquiring two
* {@link Image Images} at once. Or more generally, calling {@link #acquireLatestImage}
* with less than two images of margin, that is
* {@code (maxImages - currentAcquiredImages < 2)} will not discard as expected.
*
*
* This operation will fail by throwing an {@link IllegalStateException} if
* {@code maxImages} have been acquired with {@link #acquireLatestImage} or
* {@link #acquireNextImage}. In particular a sequence of {@link #acquireLatestImage}
* calls greater than {@link #getMaxImages} without calling {@link Image#close} in-between
* will exhaust the underlying queue. At such a time, {@link IllegalStateException}
* will be thrown until more images are
* released with {@link Image#close}.
*
*
* @return latest frame of image data, or {@code null} if no image data is available.
* @throws IllegalStateException if too many images are currently acquired
*/
public Image acquireLatestImage() {
Image image = acquireNextImage();
if (image == null) {
return null;
}
try {
for (;;) {
Image next = acquireNextImageNoThrowISE();
if (next == null) {
Image result = image;
image = null;
return result;
}
image.close();
image = next;
}
} finally {
if (image != null) {
image.close();
}
}
}
/**
* Don't throw IllegalStateException if there are too many images acquired.
*
* @return Image if acquiring succeeded, or null otherwise.
*
* @hide
*/
public Image acquireNextImageNoThrowISE() {
SurfaceImage si = new SurfaceImage(mFormat);
return acquireNextSurfaceImage(si) == ACQUIRE_SUCCESS ? si : null;
}
/**
* Attempts to acquire the next image from the underlying native implementation.
*
*
* Note that unexpected failures will throw at the JNI level.
*
*
* @param si A blank SurfaceImage.
* @return One of the {@code ACQUIRE_*} codes that determine success or failure.
*
* @see #ACQUIRE_MAX_IMAGES
* @see #ACQUIRE_NO_BUFS
* @see #ACQUIRE_SUCCESS
*/
private int acquireNextSurfaceImage(SurfaceImage si) {
synchronized (mCloseLock) {
// A null image will eventually be returned if ImageReader is already closed.
int status = ACQUIRE_NO_BUFS;
if (mIsReaderValid) {
status = nativeImageSetup(si);
}
switch (status) {
case ACQUIRE_SUCCESS:
si.mIsImageValid = true;
case ACQUIRE_NO_BUFS:
case ACQUIRE_MAX_IMAGES:
break;
default:
throw new AssertionError("Unknown nativeImageSetup return code " + status);
}
// Only keep track the successfully acquired image, as the native buffer is only mapped
// for such case.
if (status == ACQUIRE_SUCCESS) {
mAcquiredImages.add(si);
}
return status;
}
}
/**
*
* Acquire the next Image from the ImageReader's queue. Returns {@code null} if
* no new image is available.
*
*
* Warning: Consider using {@link #acquireLatestImage()} instead, as it will
* automatically release older images, and allow slower-running processing routines to catch
* up to the newest frame. Usage of {@link #acquireNextImage} is recommended for
* batch/background processing. Incorrectly using this function can cause images to appear
* with an ever-increasing delay, followed by a complete stall where no new images seem to
* appear.
*
*
*
* This operation will fail by throwing an {@link IllegalStateException} if
* {@code maxImages} have been acquired with {@link #acquireNextImage} or
* {@link #acquireLatestImage}. In particular a sequence of {@link #acquireNextImage} or
* {@link #acquireLatestImage} calls greater than {@link #getMaxImages maxImages} without
* calling {@link Image#close} in-between will exhaust the underlying queue. At such a time,
* {@link IllegalStateException} will be thrown until more images are released with
* {@link Image#close}.
*
*
* @return a new frame of image data, or {@code null} if no image data is available.
* @throws IllegalStateException if {@code maxImages} images are currently acquired
* @see #acquireLatestImage
*/
public Image acquireNextImage() {
// Initialize with reader format, but can be overwritten by native if the image
// format is different from the reader format.
SurfaceImage si = new SurfaceImage(mFormat);
int status = acquireNextSurfaceImage(si);
switch (status) {
case ACQUIRE_SUCCESS:
return si;
case ACQUIRE_NO_BUFS:
return null;
case ACQUIRE_MAX_IMAGES:
throw new IllegalStateException(
String.format(
"maxImages (%d) has already been acquired, " +
"call #close before acquiring more.", mMaxImages));
default:
throw new AssertionError("Unknown nativeImageSetup return code " + status);
}
}
/**
* Return the frame to the ImageReader for reuse.
*/
private void releaseImage(Image i) {
if (! (i instanceof SurfaceImage) ) {
throw new IllegalArgumentException(
"This image was not produced by an ImageReader");
}
SurfaceImage si = (SurfaceImage) i;
if (si.mIsImageValid == false) {
return;
}
if (si.getReader() != this || !mAcquiredImages.contains(i)) {
throw new IllegalArgumentException(
"This image was not produced by this ImageReader");
}
si.clearSurfacePlanes();
nativeReleaseImage(i);
si.mIsImageValid = false;
mAcquiredImages.remove(i);
}
/**
* Register a listener to be invoked when a new image becomes available
* from the ImageReader.
*
* @param listener
* The listener that will be run.
* @param handler
* The handler on which the listener should be invoked, or null
* if the listener should be invoked on the calling thread's looper.
* @throws IllegalArgumentException
* If no handler specified and the calling thread has no looper.
*/
public void setOnImageAvailableListener(OnImageAvailableListener listener, Handler handler) {
synchronized (mListenerLock) {
if (listener != null) {
Looper looper = handler != null ? handler.getLooper() : Looper.myLooper();
if (looper == null) {
throw new IllegalArgumentException(
"handler is null but the current thread is not a looper");
}
if (mListenerHandler == null || mListenerHandler.getLooper() != looper) {
mListenerHandler = new ListenerHandler(looper);
}
mListener = listener;
} else {
mListener = null;
mListenerHandler = null;
}
}
}
/**
* Callback interface for being notified that a new image is available.
*
*
* The onImageAvailable is called per image basis, that is, callback fires for every new frame
* available from ImageReader.
*
*/
public interface OnImageAvailableListener {
/**
* Callback that is called when a new image is available from ImageReader.
*
* @param reader the ImageReader the callback is associated with.
* @see ImageReader
* @see Image
*/
void onImageAvailable(ImageReader reader);
}
/**
* Free up all the resources associated with this ImageReader.
*
*
* After calling this method, this ImageReader can not be used. Calling
* any methods on this ImageReader and Images previously provided by
* {@link #acquireNextImage} or {@link #acquireLatestImage}
* will result in an {@link IllegalStateException}, and attempting to read from
* {@link ByteBuffer ByteBuffers} returned by an earlier
* {@link Image.Plane#getBuffer Plane#getBuffer} call will
* have undefined behavior.
*
*/
@Override
public void close() {
setOnImageAvailableListener(null, null);
if (mSurface != null) mSurface.release();
/**
* Close all outstanding acquired images before closing the ImageReader. It is a good
* practice to close all the images as soon as it is not used to reduce system instantaneous
* memory pressure. CopyOnWrite list will use a copy of current list content. For the images
* being closed by other thread (e.g., GC thread), doubling the close call is harmless. For
* the image being acquired by other threads, mCloseLock is used to synchronize close and
* acquire operations.
*/
synchronized (mCloseLock) {
mIsReaderValid = false;
for (Image image : mAcquiredImages) {
image.close();
}
mAcquiredImages.clear();
nativeClose();
}
if (mEstimatedNativeAllocBytes > 0) {
VMRuntime.getRuntime().registerNativeFree(mEstimatedNativeAllocBytes);
mEstimatedNativeAllocBytes = 0;
}
}
@Override
protected void finalize() throws Throwable {
try {
close();
} finally {
super.finalize();
}
}
/**
*
* Remove the ownership of this image from the ImageReader.
*
*
* After this call, the ImageReader no longer owns this image, and the image
* ownership can be transfered to another entity like {@link ImageWriter}
* via {@link ImageWriter#queueInputImage}. It's up to the new owner to
* release the resources held by this image. For example, if the ownership
* of this image is transfered to an {@link ImageWriter}, the image will be
* freed by the ImageWriter after the image data consumption is done.
*
*
* This method can be used to achieve zero buffer copy for use cases like
* {@link android.hardware.camera2.CameraDevice Camera2 API} PRIVATE and YUV
* reprocessing, where the application can select an output image from
* {@link ImageReader} and transfer this image directly to
* {@link ImageWriter}, where this image can be consumed by camera directly.
* For PRIVATE reprocessing, this is the only way to send input buffers to
* the {@link android.hardware.camera2.CameraDevice camera} for
* reprocessing.
*
*
* This is a package private method that is only used internally.
*
*
* @param image The image to be detached from this ImageReader.
* @throws IllegalStateException If the ImageReader or image have been
* closed, or the has been detached, or has not yet been
* acquired.
*/
void detachImage(Image image) {
if (image == null) {
throw new IllegalArgumentException("input image must not be null");
}
if (!isImageOwnedbyMe(image)) {
throw new IllegalArgumentException("Trying to detach an image that is not owned by"
+ " this ImageReader");
}
SurfaceImage si = (SurfaceImage) image;
si.throwISEIfImageIsInvalid();
if (si.isAttachable()) {
throw new IllegalStateException("Image was already detached from this ImageReader");
}
nativeDetachImage(image);
si.setDetached(true);
}
private boolean isImageOwnedbyMe(Image image) {
if (!(image instanceof SurfaceImage)) {
return false;
}
SurfaceImage si = (SurfaceImage) image;
return si.getReader() == this;
}
/**
* Called from Native code when an Event happens.
*
* This may be called from an arbitrary Binder thread, so access to the ImageReader must be
* synchronized appropriately.
*/
private static void postEventFromNative(Object selfRef) {
@SuppressWarnings("unchecked")
WeakReference weakSelf = (WeakReference)selfRef;
final ImageReader ir = weakSelf.get();
if (ir == null) {
return;
}
final Handler handler;
synchronized (ir.mListenerLock) {
handler = ir.mListenerHandler;
}
if (handler != null) {
handler.sendEmptyMessage(0);
}
}
private final int mWidth;
private final int mHeight;
private final int mFormat;
private final int mMaxImages;
private final int mNumPlanes;
private final Surface mSurface;
private int mEstimatedNativeAllocBytes;
private final Object mListenerLock = new Object();
private final Object mCloseLock = new Object();
private boolean mIsReaderValid = false;
private OnImageAvailableListener mListener;
private ListenerHandler mListenerHandler;
// Keep track of the successfully acquired Images. This need to be thread safe as the images
// could be closed by different threads (e.g., application thread and GC thread).
private List mAcquiredImages = new CopyOnWriteArrayList();
/**
* This field is used by native code, do not access or modify.
*/
private long mNativeContext;
/**
* This custom handler runs asynchronously so callbacks don't get queued behind UI messages.
*/
private final class ListenerHandler extends Handler {
public ListenerHandler(Looper looper) {
super(looper, null, true /*async*/);
}
@Override
public void handleMessage(Message msg) {
OnImageAvailableListener listener;
synchronized (mListenerLock) {
listener = mListener;
}
// It's dangerous to fire onImageAvailable() callback when the ImageReader is being
// closed, as application could acquire next image in the onImageAvailable() callback.
boolean isReaderValid = false;
synchronized (mCloseLock) {
isReaderValid = mIsReaderValid;
}
if (listener != null && isReaderValid) {
listener.onImageAvailable(ImageReader.this);
}
}
}
private class SurfaceImage extends android.media.Image {
public SurfaceImage(int format) {
mFormat = format;
}
@Override
public void close() {
ImageReader.this.releaseImage(this);
}
public ImageReader getReader() {
return ImageReader.this;
}
@Override
public int getFormat() {
throwISEIfImageIsInvalid();
int readerFormat = ImageReader.this.getImageFormat();
// Assume opaque reader always produce opaque images.
mFormat = (readerFormat == ImageFormat.PRIVATE) ? readerFormat :
nativeGetFormat(readerFormat);
return mFormat;
}
@Override
public int getWidth() {
throwISEIfImageIsInvalid();
int width;
switch(getFormat()) {
case ImageFormat.JPEG:
case ImageFormat.DEPTH_POINT_CLOUD:
case ImageFormat.RAW_PRIVATE:
width = ImageReader.this.getWidth();
break;
default:
width = nativeGetWidth();
}
return width;
}
@Override
public int getHeight() {
throwISEIfImageIsInvalid();
int height;
switch(getFormat()) {
case ImageFormat.JPEG:
case ImageFormat.DEPTH_POINT_CLOUD:
case ImageFormat.RAW_PRIVATE:
height = ImageReader.this.getHeight();
break;
default:
height = nativeGetHeight();
}
return height;
}
@Override
public long getTimestamp() {
throwISEIfImageIsInvalid();
return mTimestamp;
}
@Override
public void setTimestamp(long timestampNs) {
throwISEIfImageIsInvalid();
mTimestamp = timestampNs;
}
@Override
public Plane[] getPlanes() {
throwISEIfImageIsInvalid();
if (mPlanes == null) {
mPlanes = nativeCreatePlanes(ImageReader.this.mNumPlanes, ImageReader.this.mFormat);
}
// Shallow copy is fine.
return mPlanes.clone();
}
@Override
protected final void finalize() throws Throwable {
try {
close();
} finally {
super.finalize();
}
}
@Override
boolean isAttachable() {
throwISEIfImageIsInvalid();
return mIsDetached.get();
}
@Override
ImageReader getOwner() {
throwISEIfImageIsInvalid();
return ImageReader.this;
}
@Override
long getNativeContext() {
throwISEIfImageIsInvalid();
return mNativeBuffer;
}
private void setDetached(boolean detached) {
throwISEIfImageIsInvalid();
mIsDetached.getAndSet(detached);
}
private void clearSurfacePlanes() {
// Image#getPlanes may not be called before the image is closed.
if (mIsImageValid && mPlanes != null) {
for (int i = 0; i < mPlanes.length; i++) {
if (mPlanes[i] != null) {
mPlanes[i].clearBuffer();
mPlanes[i] = null;
}
}
}
}
private class SurfacePlane extends android.media.Image.Plane {
// SurfacePlane instance is created by native code when SurfaceImage#getPlanes() is
// called
private SurfacePlane(int rowStride, int pixelStride, ByteBuffer buffer) {
mRowStride = rowStride;
mPixelStride = pixelStride;
mBuffer = buffer;
/**
* Set the byteBuffer order according to host endianness (native
* order), otherwise, the byteBuffer order defaults to
* ByteOrder.BIG_ENDIAN.
*/
mBuffer.order(ByteOrder.nativeOrder());
}
@Override
public ByteBuffer getBuffer() {
throwISEIfImageIsInvalid();
return mBuffer;
}
@Override
public int getPixelStride() {
SurfaceImage.this.throwISEIfImageIsInvalid();
if (ImageReader.this.mFormat == ImageFormat.RAW_PRIVATE) {
throw new UnsupportedOperationException(
"getPixelStride is not supported for RAW_PRIVATE plane");
}
return mPixelStride;
}
@Override
public int getRowStride() {
SurfaceImage.this.throwISEIfImageIsInvalid();
if (ImageReader.this.mFormat == ImageFormat.RAW_PRIVATE) {
throw new UnsupportedOperationException(
"getRowStride is not supported for RAW_PRIVATE plane");
}
return mRowStride;
}
private void clearBuffer() {
// Need null check first, as the getBuffer() may not be called before an image
// is closed.
if (mBuffer == null) {
return;
}
if (mBuffer.isDirect()) {
NioUtils.freeDirectBuffer(mBuffer);
}
mBuffer = null;
}
final private int mPixelStride;
final private int mRowStride;
private ByteBuffer mBuffer;
}
/**
* This field is used to keep track of native object and used by native code only.
* Don't modify.
*/
private long mNativeBuffer;
/**
* This field is set by native code during nativeImageSetup().
*/
private long mTimestamp;
private SurfacePlane[] mPlanes;
private int mFormat = ImageFormat.UNKNOWN;
// If this image is detached from the ImageReader.
private AtomicBoolean mIsDetached = new AtomicBoolean(false);
private synchronized native SurfacePlane[] nativeCreatePlanes(int numPlanes,
int readerFormat);
private synchronized native int nativeGetWidth();
private synchronized native int nativeGetHeight();
private synchronized native int nativeGetFormat(int readerFormat);
}
private synchronized native void nativeInit(Object weakSelf, int w, int h,
int fmt, int maxImgs);
private synchronized native void nativeClose();
private synchronized native void nativeReleaseImage(Image i);
private synchronized native Surface nativeGetSurface();
private synchronized native int nativeDetachImage(Image i);
/**
* @return A return code {@code ACQUIRE_*}
*
* @see #ACQUIRE_SUCCESS
* @see #ACQUIRE_NO_BUFS
* @see #ACQUIRE_MAX_IMAGES
*/
private synchronized native int nativeImageSetup(Image i);
/**
* We use a class initializer to allow the native code to cache some
* field offsets.
*/
private static native void nativeClassInit();
static {
System.loadLibrary("media_jni");
nativeClassInit();
}
}