Reuse callback buffers in the Visualizer. (449725f9) · Commits · e / os / android_frameworks_base

media/java/android/media/audiofx/Visualizer.java

+6 −0

Original line number	Diff line number	Diff line
		@@ -396,6 +396,9 @@ public class Visualizer {
		public interface OnDataCaptureListener {
		/**
		* Method called when a new waveform capture is available.
		* <p>Data in the waveform buffer is valid only within the scope of the callback.
		* Applications which needs access to the waveform data after returning from the callback
		* should make a copy of the data instead of holding a reference.
		* @param visualizer Visualizer object on which the listener is registered.
		* @param waveform array of bytes containing the waveform representation.
		* @param samplingRate sampling rate of the audio visualized.
		@@ -404,6 +407,9 @@ public class Visualizer {

		/**
		* Method called when a new frequency capture is available.
		* <p>Data in the fft buffer is valid only within the scope of the callback.
		* Applications which needs access to the fft data after returning from the callback
		* should make a copy of the data instead of holding a reference.
		* @param visualizer Visualizer object on which the listener is registered.
		* @param fft array of bytes containing the frequency representation.
		* @param samplingRate sampling rate of the audio visualized.

media/jni/audioeffect/android_media_Visualizer.cpp

+80 −6

Original line number	Diff line number	Diff line
		@@ -23,6 +23,7 @@
		#include <nativehelper/jni.h>
		#include <nativehelper/JNIHelp.h>
		#include <android_runtime/AndroidRuntime.h>
		#include <utils/threads.h>
		#include "media/Visualizer.h"

		using namespace android;
		@@ -54,6 +55,43 @@ static fields_t fields;
		struct visualizer_callback_cookie {
		jclass visualizer_class; // Visualizer class
		jobject visualizer_ref; // Visualizer object instance

		// Lazily allocated arrays used to hold callback data provided to java
		// applications. These arrays are allocated during the first callback and
		// reallocated when the size of the callback data changes. Allocating on
		// demand and saving the arrays means that applications cannot safely hold a
		// reference to the provided data (they need to make a copy if they want to
		// hold onto outside of the callback scope), but it avoids GC thrash caused
		// by constantly allocating and releasing arrays to hold callback data.
		Mutex callback_data_lock;
		jbyteArray waveform_data;
		jbyteArray fft_data;

		visualizer_callback_cookie() {
		waveform_data = NULL;
		fft_data = NULL;
		}

		~visualizer_callback_cookie() {
		cleanupBuffers();
		}

		void cleanupBuffers() {
		AutoMutex lock(&callback_data_lock);
		if (waveform_data \|\| fft_data) {
		JNIEnv *env = AndroidRuntime::getJNIEnv();

		if (waveform_data) {
		env->DeleteGlobalRef(waveform_data);
		waveform_data = NULL;
		}

		if (fft_data) {
		env->DeleteGlobalRef(fft_data);
		fft_data = NULL;
		}
		}
		}
		};

		// ----------------------------------------------------------------------------
		@@ -66,7 +104,6 @@ class visualizerJniStorage {

		~visualizerJniStorage() {
		}

		};


		@@ -93,6 +130,26 @@ static jint translateError(int code) {


		// ----------------------------------------------------------------------------
		static void ensureArraySize(JNIEnv env, jbyteArray array, uint32_t size) {
		if (NULL != *array) {
		uint32_t len = env->GetArrayLength(*array);
		if (len == size)
		return;

		env->DeleteGlobalRef(*array);
		*array = NULL;
		}

		jbyteArray localRef = env->NewByteArray(size);
		if (NULL != localRef) {
		// Promote to global ref.
		*array = (jbyteArray)env->NewGlobalRef(localRef);

		// Release our (now pointless) local ref.
		env->DeleteLocalRef(localRef);
		}
		}

		static void captureCallback(void* user,
		uint32_t waveformSize,
		uint8_t *waveform,
		@@ -106,6 +163,7 @@ static void captureCallback(void* user,

		visualizer_callback_cookie callbackInfo = (visualizer_callback_cookie )user;
		JNIEnv *env = AndroidRuntime::getJNIEnv();
		AutoMutex lock(&callbackInfo->callback_data_lock);

		ALOGV("captureCallback: callbackInfo %p, visualizer_ref %p visualizer_class %p",
		callbackInfo,
		@@ -118,7 +176,11 @@ static void captureCallback(void* user,
		}

		if (waveformSize != 0 && waveform != NULL) {
		jbyteArray jArray = env->NewByteArray(waveformSize);
		jbyteArray jArray;

		ensureArraySize(env, &callbackInfo->waveform_data, waveformSize);
		jArray = callbackInfo->waveform_data;

		if (jArray != NULL) {
		jbyte *nArray = env->GetByteArrayElements(jArray, NULL);
		memcpy(nArray, waveform, waveformSize);
		@@ -131,12 +193,15 @@ static void captureCallback(void* user,
		samplingrate,
		0,
		jArray);
		env->DeleteLocalRef(jArray);
		}
		}

		if (fftSize != 0 && fft != NULL) {
		jbyteArray jArray = env->NewByteArray(fftSize);
		jbyteArray jArray;

		ensureArraySize(env, &callbackInfo->fft_data, fftSize);
		jArray = callbackInfo->fft_data;

		if (jArray != NULL) {
		jbyte *nArray = env->GetByteArrayElements(jArray, NULL);
		memcpy(nArray, fft, fftSize);
		@@ -149,7 +214,6 @@ static void captureCallback(void* user,
		samplingrate,
		0,
		jArray);
		env->DeleteLocalRef(jArray);
		}
		}

		@@ -345,7 +409,17 @@ android_media_visualizer_native_setEnabled(JNIEnv *env, jobject thiz, jboolean e
		return VISUALIZER_ERROR_NO_INIT;
		}

		return translateError(lpVisualizer->setEnabled(enabled));
		jint retVal = translateError(lpVisualizer->setEnabled(enabled));

		if (!enabled) {
		visualizerJniStorage* lpJniStorage = (visualizerJniStorage *)env->GetIntField(
		thiz, fields.fidJniData);

		if (NULL != lpJniStorage)
		lpJniStorage->mCallbackData.cleanupBuffers();
		}

		return retVal;
		}

		static jboolean