Renaming project to HelloLowLatencyOutput, adding licenses and readme

Author: Don Turner

CONTRIBUTING.md

@@ -0,0 +1,56 @@
+# How to become a contributor and submit your own code
+
+## Contributor License Agreements
+
+We'd love to accept your sample apps and patches! Before we can take them, we 
+have to jump a couple of legal hurdles.
+
+Please fill out either the individual or corporate Contributor License Agreement
+(CLA).
+
+  * If you are an individual writing original source code and you're sure you
+    own the intellectual property, then you'll need to sign an [individual CLA]
+    (http://code.google.com/legal/individual-cla-v1.0.html).
+  * If you work for a company that wants to allow you to contribute your work,
+    then you'll need to sign a [corporate CLA]
+    (http://code.google.com/legal/corporate-cla-v1.0.html).
+
+Follow either of the two links above to access the appropriate CLA and
+instructions for how to sign and return it. Once we receive it, we'll be able to
+accept your pull requests.
+
+## Contributing a Patch
+
+1. Sign a Contributor License Agreement, if you have not yet done so (see
+   details above).
+1. Create your change to the repo in question.
+    * Fork the desired repo, develop and test your code changes.
+    * Ensure that your code is clear and comprehensible.
+    * Ensure that your code has an appropriate set of unit tests which all pass.
+1. Submit a pull request.
+1. The repo owner will review your request. If it is approved, the change will
+   be merged. If it needs additional work, the repo owner will respond with
+   useful comments.
+
+## Contributing a New Sample App
+
+1. Sign a Contributor License Agreement, if you have not yet done so (see
+   details above).
+1. Create your own repo for your app following this naming convention:
+    * mirror-{app-name}-{language or plaform}
+    * apps: quickstart, photohunt-server, photohunt-client
+    * example:  mirror-quickstart-android
+    * For multi-language apps, concatenate the primary languages like this:
+      mirror-photohunt-server-java-python.
+
+1. Create your sample app in this repo.
+    * Be sure to clone the README.md, CONTRIBUTING.md and LICENSE files from the
+      googlecast repo.
+    * Ensure that your code is clear and comprehensible.
+    * Ensure that your code has an appropriate set of unit tests which all pass.
+    * Instructional value is the top priority when evaluating new app proposals for
+      this collection of repos.
+1. Submit a request to fork your repo in googlecast organization.
+1. The repo owner will review your request. If it is approved, the sample will
+   be merged. If it needs additional work, the repo owner will respond with 
+   useful comments.

HelloLowLatency/app/src/main/res/values/strings.xml

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module external.linked.project.id="HelloLowLatencyOutput" external.linked.project.path="$MODULE_DIR$" external.root.project.path="$MODULE_DIR$" external.system.id="GRADLE" external.system.module.group="" external.system.module.version="unspecified" type="JAVA_MODULE" version="4">
+  <component name="FacetManager">
+    <facet type="java-gradle" name="Java-Gradle">
+      <configuration>
+        <option name="BUILD_FOLDER_PATH" value="$MODULE_DIR$/build" />
+        <option name="BUILDABLE" value="false" />
+      </configuration>
+    </facet>
+  </component>
+  <component name="NewModuleRootManager" LANGUAGE_LEVEL="JDK_1_7" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <excludeFolder url="file://$MODULE_DIR$/.gradle" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>

HelloLowLatency/HelloLowLatency.iml HelloLowLatencyOutput/HelloLowLatency.iml

@@ -0,0 +1,8 @@
+Low Latency Audio Output
+========================
+
+This sample demonstrates how to achieve the lowest possible output latency on an Android device. 
+
+TODO
+---
+- App crashes on orientation change

HelloLowLatencyOutput/HelloLowLatencyOutput.iml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<module external.linked.project.id=":app" external.linked.project.path="$MODULE_DIR$" external.root.project.path="$MODULE_DIR$/.." external.system.id="GRADLE" external.system.module.group="HelloLowLatency" external.system.module.version="unspecified" type="JAVA_MODULE" version="4">
+<module external.linked.project.id=":app" external.linked.project.path="$MODULE_DIR$" external.root.project.path="$MODULE_DIR$/.." external.system.id="GRADLE" external.system.module.group="HelloLowLatencyOutput" external.system.module.version="unspecified" type="JAVA_MODULE" version="4">
   <component name="FacetManager">
     <facet type="android-gradle" name="Android-Gradle">
       <configuration>
@@ -71,6 +71,8 @@
       <excludeFolder url="file://$MODULE_DIR$/build/intermediates/dependency-cache" />
       <excludeFolder url="file://$MODULE_DIR$/build/intermediates/dex" />
       <excludeFolder url="file://$MODULE_DIR$/build/intermediates/dex-cache" />
+      <excludeFolder url="file://$MODULE_DIR$/build/intermediates/exploded-aar/com.android.support/appcompat-v7/23.0.1/jars" />
+      <excludeFolder url="file://$MODULE_DIR$/build/intermediates/exploded-aar/com.android.support/support-v4/23.0.1/jars" />
       <excludeFolder url="file://$MODULE_DIR$/build/intermediates/incremental" />
       <excludeFolder url="file://$MODULE_DIR$/build/intermediates/jacoco" />
       <excludeFolder url="file://$MODULE_DIR$/build/intermediates/javaResources" />
@@ -86,10 +88,10 @@
       <excludeFolder url="file://$MODULE_DIR$/build/outputs" />
       <excludeFolder url="file://$MODULE_DIR$/build/tmp" />
     </content>
-    <orderEntry type="jdk" jdkName="Android API 22 Platform" jdkType="Android SDK" />
+    <orderEntry type="jdk" jdkName="Android API 23 Platform" jdkType="Android SDK" />
     <orderEntry type="sourceFolder" forTests="false" />
-    <orderEntry type="library" exported="" name="support-v4-22.2.0" level="project" />
-    <orderEntry type="library" exported="" name="support-annotations-22.2.0" level="project" />
-    <orderEntry type="library" exported="" name="appcompat-v7-22.2.0" level="project" />
+    <orderEntry type="library" exported="" name="appcompat-v7-23.0.1" level="project" />
+    <orderEntry type="library" exported="" name="support-v4-23.0.1" level="project" />
+    <orderEntry type="library" exported="" name="support-annotations-23.0.1" level="project" />
   </component>
 </module>

HelloLowLatencyOutput/README

@@ -2,20 +2,20 @@ apply plugin: 'com.android.model.application'
 
 model {
     android{
-        compileSdkVersion = 22
-        buildToolsVersion = "22.0.1"
+        compileSdkVersion = 23
+        buildToolsVersion = "23.0.1"
 
         defaultConfig.with {
             minSdkVersion.apiLevel = 22
             targetSdkVersion.apiLevel = 22
-            applicationId = "com.example.hellolowlatency"
+            applicationId = "com.example.hellolowlatencyoutput"
             versionName = "3.0"
             versionCode = 3
         }
     }
 
     android.ndk {
-        moduleName += "hello_low_latency"
+        moduleName += "hello_low_latency_output"
         ldLibs += "OpenSLES"
         ldLibs += "log"
     }
@@ -25,10 +25,13 @@ model {
             isMinifyEnabled = false
             proguardFiles += file('proguard-rules.pro')
         }
+        debug {
+            isJniDebuggable = true
+        }
     }
 }
 
 dependencies {
     compile fileTree(dir: 'libs', include: ['*.jar'])
-    compile 'com.android.support:appcompat-v7:22.2.0'
+    compile 'com.android.support:appcompat-v7:23.0.1'
 }

HelloLowLatency/app/.gitignore HelloLowLatencyOutput/app/.gitignore

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
-    package="com.example.proaudio.hellolowlatency" >
+    package="com.example.hellolowlatencyoutput" >
 
     <application
         android:allowBackup="true"
@@ -19,5 +19,5 @@
 
     </application>
 
-    <uses-feature android:name="android.hardware.audio.low_latency" android:required="false" />
+    <uses-feature android:name="android.hardware.audio.low_latency" android:required="true" />
 </manifest>

HelloLowLatency/app/app.iml HelloLowLatencyOutput/app/app.iml

@@ -1,4 +1,20 @@
-package com.example.proaudio.hellolowlatency;
+/*
+ * Copyright 2015 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 com.example.hellolowlatencyoutput;
 
 import android.content.Context;
 import android.content.pm.PackageManager;
@@ -13,7 +29,7 @@
 public class MainActivity extends AppCompatActivity {
 
     static {
-        System.loadLibrary("hello_low_latency");
+        System.loadLibrary("hello_low_latency_output");
     }
 
     public static native void playTone();
@@ -35,7 +51,6 @@ protected void onCreate(Bundle savedInstanceState) {
         //Check for low latency feature
         PackageManager pm = getPackageManager();
         boolean claimsFeature = pm.hasSystemFeature(PackageManager.FEATURE_AUDIO_LOW_LATENCY);
-
         log("Has low latency audio feature? " + claimsFeature);
 
         //Check for optimal output sample rate and buffer size

HelloLowLatency/app/build.gradle HelloLowLatencyOutput/app/build.gradle

@@ -1,3 +1,19 @@
+/*
+ * Copyright 2015 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.
+ */
+
 #include <assert.h>
 #include <jni.h>
 #include <math.h>
@@ -12,28 +28,27 @@
 
 // logging
 #include <android/log.h>
-#define APPNAME "HelloLowLatency"
+#define APPNAME "HelloLowLatencyOutput"
 
 // engine interfaces
 static SLObjectItf engineObject = NULL;
-static SLEngineItf engineEngine;
+static SLEngineItf engineEngine = NULL;
 
 // output mix interfaces
 static SLObjectItf outputMixObject = NULL;
 
 // buffer queue player interfaces
 static SLObjectItf bqPlayerObject = NULL;
-static SLPlayItf bqPlayerPlay;
-static SLAndroidSimpleBufferQueueItf bqPlayerBufferQueue;
+static SLPlayItf bqPlayerPlay = NULL;
+static SLAndroidSimpleBufferQueueItf bqPlayerBufferQueue = NULL;
 
-#define CHANNELS 1
+#define CHANNELS 1 // 1 for mono, 2 for stereo
 #define TWO_PI (3.14159 * 2)
 
 // Each short represents a 16-bit audio sample
-static short* squareWaveBuffer;
-static short* sineWaveBuffer;
-static short* silenceBuffer;
-static unsigned int bufferSizeInBytes;
+static short* sineWaveBuffer = NULL;
+static short* silenceBuffer = NULL;
+static unsigned int bufferSizeInBytes = 0;
 
 #define MAXIMUM_AMPLITUDE_VALUE 32767
 
@@ -45,10 +60,10 @@ static unsigned buffersRemaining = 0;
 /**
  * Create wave tables with the specified number of frames
  */
-void createWaveTables(int frames){
+void createWaveTables(unsigned int frames){
 
     // First figure out how many samples we need and allocate memory for the tables
-    int numSamples = frames * CHANNELS;
+    unsigned int numSamples = frames * CHANNELS;
     silenceBuffer = malloc(sizeof(*silenceBuffer) * numSamples);
     sineWaveBuffer = malloc(sizeof(*sineWaveBuffer) * numSamples);
     bufferSizeInBytes = numSamples * 2;
@@ -62,15 +77,15 @@ void createWaveTables(int frames){
                         bufferSizeInBytes);
 
     // Now create the sine wave - we'll just create a single cycle which fills the entire table
-    float phaseIncrement = TWO_PI/frames;
+    float phaseIncrement = (float) TWO_PI/frames;
     float currentPhase = 0.0;
 
     unsigned int i;
     unsigned int j;
 
     for (i = 0; i < frames; i++) {
 
-        short sampleValue = sin(currentPhase) * MAXIMUM_AMPLITUDE_VALUE;
+        short sampleValue = (short) (sin(currentPhase) * MAXIMUM_AMPLITUDE_VALUE);
 
         for (j = 0; j < CHANNELS; j++){
             sineWaveBuffer[(i*CHANNELS)+j] = sampleValue;
@@ -84,11 +99,10 @@ void createWaveTables(int frames){
 // this callback handler is called every time a buffer finishes playing
 void bqPlayerCallback(SLAndroidSimpleBufferQueueItf bq, void *context)
 {
+    if (bq == NULL) __android_log_print(ANDROID_LOG_ERROR, APPNAME, "buffer queue was null");
     assert(bq == bqPlayerBufferQueue);
     assert(NULL == context);
 
-    SLresult result;
-
     short* bufferPtr;
 
     if (buffersRemaining > 0) {
@@ -102,18 +116,18 @@ void bqPlayerCallback(SLAndroidSimpleBufferQueueItf bq, void *context)
         bufferPtr = silenceBuffer;
     }
 
-    result = (*bqPlayerBufferQueue)->Enqueue(bqPlayerBufferQueue, bufferPtr, bufferSizeInBytes);
+    SLresult result = (*bqPlayerBufferQueue)->Enqueue(bqPlayerBufferQueue, bufferPtr, bufferSizeInBytes);
     assert(SL_RESULT_SUCCESS == result);
 }
 
-void Java_com_example_proaudio_hellolowlatency_MainActivity_playTone(JNIEnv* env, jclass clazz){
+void Java_com_example_hellolowlatencyoutput_MainActivity_playTone(JNIEnv* env, jclass clazz){
 
     __android_log_print(ANDROID_LOG_VERBOSE, APPNAME, "Playing tone");
     buffersRemaining = BUFFERS_TO_PLAY;
 }
 
 // create the engine and output mix objects
-void Java_com_example_proaudio_hellolowlatency_MainActivity_createEngine(JNIEnv* env, jclass clazz)
+void Java_com_example_hellolowlatencyoutput_MainActivity_createEngine(JNIEnv* env, jclass clazz)
 {
     __android_log_print(ANDROID_LOG_VERBOSE, APPNAME, "Creating audio engine");
 
@@ -147,14 +161,14 @@ void Java_com_example_proaudio_hellolowlatency_MainActivity_createEngine(JNIEnv*
 
 
 // create buffer queue audio player
-void Java_com_example_proaudio_hellolowlatency_MainActivity_createBufferQueueAudioPlayer(JNIEnv* env,
+void Java_com_example_hellolowlatencyoutput_MainActivity_createBufferQueueAudioPlayer(JNIEnv* env,
         jclass clazz, jint optimalFrameRate, jint optimalFramesPerBuffer)
 {
     __android_log_print(ANDROID_LOG_VERBOSE, APPNAME, "Creating audio player with frame rate %d and frames per buffer %d",
                         optimalFrameRate, optimalFramesPerBuffer);
 
     // create the wave tables which we'll use as the audio signal source
-    createWaveTables(optimalFramesPerBuffer);
+    createWaveTables((unsigned int)optimalFramesPerBuffer);
 
     SLresult result;
 

HelloLowLatency/app/proguard-rules.pro HelloLowLatencyOutput/app/proguard-rules.pro

@@ -0,0 +1,3 @@
+<resources>
+    <string name="app_name">HelloLowLatencyOutput</string>
+</resources>