Update READMEs with new local build instructions

Issue: #2851
Issue: #2974

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=160290097

README.md

@@ -20,6 +20,11 @@ and extend, and can be updated through Play Store application updates.
 
 ## Using ExoPlayer ##
 
+ExoPlayer modules can be obtained via jCenter. It's also possible to clone the
+repository and depend on the modules locally.
+
+### Via jCenter ###
+
 The easiest way to get started using ExoPlayer is to add it as a gradle
 dependency. You need to make sure you have the jcenter repository included in
 the `build.gradle` file in the root of your project:
@@ -64,6 +69,39 @@ latest versions, see the [Release notes][].
 [Bintray]: https://bintray.com/google/exoplayer
 [Release notes]: https://github.com/google/ExoPlayer/blob/release-v2/RELEASENOTES.md
 
+### Locally ###
+
+Cloning the repository and depending on the modules locally is required when
+using some ExoPlayer extension modules. It's also a suitable approach if you
+want to make local changes to ExoPlayer, or if you want to use a development
+branch.
+
+First, clone the repository into a local directory and checkout the desired
+branch:
+
+```sh
+git clone https://github.com/google/ExoPlayer.git
+git checkout release-v2
+```
+
+Next, add the following to your project's `settings.gradle` file, replacing
+`path/to/exoplayer` with the path to your local copy:
+
+```gradle
+gradle.ext.exoplayerRoot = 'path/to/exoplayer'
+gradle.ext.exoplayerModulePrefix = 'exoplayer-'
+apply from: new File(gradle.ext.exoplayerRoot, 'core_settings.gradle')
+```
+
+You should now see the ExoPlayer modules appear as part of your project. You can
+depend on them as you would on any other local module, for example:
+
+```gradle
+compile project(':exoplayer-library-core')
+compile project(':exoplayer-library-dash')
+compile project(':exoplayer-library-ui)
+```
+
 ## Developing ExoPlayer ##
 
 #### Project branches ####

extensions/cronet/README.md

@@ -11,13 +11,10 @@ The Cronet Extension is an [HttpDataSource][] implementation using [Cronet][].
 
 ## Build Instructions ##
 
-* Checkout ExoPlayer along with Extensions:
+To use this extension you need to clone the ExoPlayer repository and depend on
-
+its modules locally. Instructions for doing this can be found in ExoPlayer's
-```
+[top level README][]. In addition, it's necessary to get the Cronet libraries
-git clone https://github.com/google/ExoPlayer.git
+and enable the extension:
-```
-
-* Get the Cronet libraries:
 
 1. Find the latest Cronet release [here][] and navigate to its `Release/cronet`
    directory
@@ -27,6 +24,12 @@ git clone https://github.com/google/ExoPlayer.git
 1. Copy the content of the downloaded `libs` directory into the `jniLibs`
    directory of this extension
 
-* In ExoPlayer's `settings.gradle` file, uncomment the Cronet extension
+* In your `settings.gradle` file, add the following line before the line that
+  applies `core_settings.gradle`:
 
+```gradle
+gradle.ext.exoplayerIncludeCronetExtension = true;
+```
+
+[top level README]: https://github.com/google/ExoPlayer/blob/release-v2/README.md
 [here]: https://console.cloud.google.com/storage/browser/chromium-cronet/android

extensions/ffmpeg/README.md

@@ -9,11 +9,10 @@ audio.
 
 ## Build instructions ##
 
-* Checkout ExoPlayer along with Extensions
+To use this extension you need to clone the ExoPlayer repository and depend on
-
+its modules locally. Instructions for doing this can be found in ExoPlayer's
-```
+[top level README][]. In addition, it's necessary to build the extension's
-git clone https://github.com/google/ExoPlayer.git
+native components as follows:
-```
 
 * Set the following environment variables:
 
@@ -25,8 +24,6 @@ FFMPEG_EXT_PATH="${EXOPLAYER_ROOT}/extensions/ffmpeg/src/main"
 
 * Download the [Android NDK][] and set its location in an environment variable:
 
-[Android NDK]: https://developer.android.com/tools/sdk/ndk/index.html
-
 ```
 NDK_PATH="<path to Android NDK>"
 ```
@@ -106,20 +103,5 @@ cd "${FFMPEG_EXT_PATH}"/jni && \
 ${NDK_PATH}/ndk-build APP_ABI="armeabi-v7a arm64-v8a x86" -j4
 ```
 
-* In your project, you can add a dependency on the extension by using a rule
+[top level README]: https://github.com/google/ExoPlayer/blob/release-v2/README.md
-  like this:
+[Android NDK]: https://developer.android.com/tools/sdk/ndk/index.html
-
-```
-// in settings.gradle
-include ':..:ExoPlayer:library'
-include ':..:ExoPlayer:extension-ffmpeg'
-
-// in build.gradle
-dependencies {
-    compile project(':..:ExoPlayer:library')
-    compile project(':..:ExoPlayer:extension-ffmpeg')
-}
-```
-
-* Now, when you build your app, the extension will be built and the native
-  libraries will be packaged along with the APK.

extensions/flac/README.md

@@ -10,11 +10,10 @@ ExoPlayer to play Flac audio on Android devices.
 
 ## Build Instructions ##
 
-* Checkout ExoPlayer along with Extensions:
+To use this extension you need to clone the ExoPlayer repository and depend on
-
+its modules locally. Instructions for doing this can be found in ExoPlayer's
-```
+[top level README][]. In addition, it's necessary to build the extension's
-git clone https://github.com/google/ExoPlayer.git
+native components as follows:
-```
 
 * Set the following environment variables:
 
@@ -26,8 +25,6 @@ FLAC_EXT_PATH="${EXOPLAYER_ROOT}/extensions/flac/src/main"
 
 * Download the [Android NDK][] and set its location in an environment variable:
 
-[Android NDK]: https://developer.android.com/tools/sdk/ndk/index.html
-
 ```
 NDK_PATH="<path to Android NDK>"
 ```
@@ -47,20 +44,5 @@ cd "${FLAC_EXT_PATH}"/jni && \
 ${NDK_PATH}/ndk-build APP_ABI=all -j4
 ```
 
-* In your project, you can add a dependency to the Flac Extension by using a
+[top level README]: https://github.com/google/ExoPlayer/blob/release-v2/README.md
-  rule like this:
+[Android NDK]: https://developer.android.com/tools/sdk/ndk/index.html
-
-```
-// in settings.gradle
-include ':..:ExoPlayer:library'
-include ':..:ExoPlayer:extension-flac'
-
-// in build.gradle
-dependencies {
-    compile project(':..:ExoPlayer:library')
-    compile project(':..:ExoPlayer:extension-flac')
-}
-```
-
-* Now, when you build your app, the Flac extension will be built and the native
-  libraries will be packaged along with the APK.

extensions/gvr/README.md

@@ -6,7 +6,10 @@ The GVR extension wraps the [Google VR SDK for Android][]. It provides a
 GvrAudioProcessor, which uses [GvrAudioSurround][] to provide binaural rendering
 of surround sound and ambisonic soundfields.
 
-## Using the extension ##
+[Google VR SDK for Android]: https://developers.google.com/vr/android/
+[GvrAudioSurround]: https://developers.google.com/vr/android/reference/com/google/vr/sdk/audio/GvrAudioSurround
+
+## Getting the extension ##
 
 The easiest way to use the extension is to add it as a gradle dependency. You
 need to make sure you have the jcenter repository included in the `build.gradle`
@@ -27,12 +30,15 @@ compile 'com.google.android.exoplayer:extension-gvr:rX.X.X'
 where `rX.X.X` is the version, which must match the version of the ExoPlayer
 library being used.
 
-## Using GvrAudioProcessor ##
+Alternatively, you can clone the ExoPlayer repository and depend on the module
+locally. Instructions for doing this can be found in ExoPlayer's
+[top level README][].
+
+## Using the extension ##
 
 * If using SimpleExoPlayer, override SimpleExoPlayer.buildAudioProcessors to
   return a GvrAudioProcessor.
 * If constructing renderers directly, pass a GvrAudioProcessor to
   MediaCodecAudioRenderer's constructor.
 
-[Google VR SDK for Android]: https://developers.google.com/vr/android/
+[top level README]: https://github.com/google/ExoPlayer/blob/release-v2/README.md
-[GvrAudioSurround]: https://developers.google.com/vr/android/reference/com/google/vr/sdk/audio/GvrAudioSurround

extensions/ima/README.md

@@ -9,6 +9,14 @@ alongside content.
 [IMA]: https://developers.google.com/interactive-media-ads/docs/sdks/android/
 [MediaSource]: https://github.com/google/ExoPlayer/blob/release-v2/library/core/src/main/java/com/google/android/exoplayer2/source/MediaSource.java
 
+## Getting the extension ##
+
+To use this extension you need to clone the ExoPlayer repository and depend on
+its modules locally. Instructions for doing this can be found in ExoPlayer's
+[top level README][].
+
+[top level README]: https://github.com/google/ExoPlayer/blob/release-v2/README.md
+
 ## Using the extension ##
 
 Pass a single-window content `MediaSource` to `ImaAdsMediaSource`'s constructor,
@@ -21,6 +29,7 @@ select and build one of the `withExtensions` build variants of the demo app in
 Android Studio. You can find IMA test content in the "IMA sample ad tags"
 section of the app.
 
+[top level README]: https://github.com/google/ExoPlayer/blob/release-v2/README.md
 [sample ad tags]: https://developers.google.com/interactive-media-ads/docs/sdks/android/tags
 
 ## Known issues ##

extensions/okhttp/README.md

@@ -5,19 +5,12 @@
 The OkHttp Extension is an [HttpDataSource][] implementation using Square's
 [OkHttp][].
 
-## Using the extension ##
+[HttpDataSource]: https://google.github.io/ExoPlayer/doc/reference/com/google/android/exoplayer2/upstream/HttpDataSource.html
+[OkHttp]: https://square.github.io/okhttp/
 
-The easiest way to use the extension is to add it as a gradle dependency. You
+## Getting the extension ##
-need to make sure you have the jcenter repository included in the `build.gradle`
-file in the root of your project:
 
-```gradle
+The easiest way to use the extension is to add it as a gradle dependency:
-repositories {
-    jcenter()
-}
-```
-
-Next, include the following in your module's `build.gradle` file:
 
 ```gradle
 compile 'com.google.android.exoplayer:extension-okhttp:rX.X.X'
@@ -26,5 +19,8 @@ compile 'com.google.android.exoplayer:extension-okhttp:rX.X.X'
 where `rX.X.X` is the version, which must match the version of the ExoPlayer
 library being used.
 
-[HttpDataSource]: https://google.github.io/ExoPlayer/doc/reference/com/google/android/exoplayer2/upstream/HttpDataSource.html
+Alternatively, you can clone the ExoPlayer repository and depend on the module
-[OkHttp]: https://square.github.io/okhttp/
+locally. Instructions for doing this can be found in ExoPlayer's
+[top level README][].
+
+[top level README]: https://github.com/google/ExoPlayer/blob/release-v2/README.md

extensions/opus/README.md

@@ -10,11 +10,10 @@ ExoPlayer to play Opus audio on Android devices.
 
 ## Build Instructions ##
 
-* Checkout ExoPlayer along with Extensions:
+To use this extension you need to clone the ExoPlayer repository and depend on
-
+its modules locally. Instructions for doing this can be found in ExoPlayer's
-```
+[top level README][]. In addition, it's necessary to build the extension's
-git clone https://github.com/google/ExoPlayer.git
+native components as follows:
-```
 
 * Set the following environment variables:
 
@@ -26,8 +25,6 @@ OPUS_EXT_PATH="${EXOPLAYER_ROOT}/extensions/opus/src/main"
 
 * Download the [Android NDK][] and set its location in an environment variable:
 
-[Android NDK]: https://developer.android.com/tools/sdk/ndk/index.html
-
 ```
 NDK_PATH="<path to Android NDK>"
 ```
@@ -52,23 +49,8 @@ cd "${OPUS_EXT_PATH}"/jni && \
 ${NDK_PATH}/ndk-build APP_ABI=all -j4
 ```
 
-* In your project, you can add a dependency to the Opus Extension by using a
+[top level README]: https://github.com/google/ExoPlayer/blob/release-v2/README.md
-rule like this:
+[Android NDK]: https://developer.android.com/tools/sdk/ndk/index.html
-
-```
-// in settings.gradle
-include ':..:ExoPlayer:library'
-include ':..:ExoPlayer:extension-opus'
-
-// in build.gradle
-dependencies {
-    compile project(':..:ExoPlayer:library')
-    compile project(':..:ExoPlayer:extension-opus')
-}
-```
-
-* Now, when you build your app, the Opus extension will be built and the native
-  libraries will be packaged along with the APK.
 
 ## Notes ##
 

extensions/vp9/README.md

@@ -10,11 +10,10 @@ VP9 video on Android devices.
 
 ## Build Instructions ##
 
-* Checkout ExoPlayer along with Extensions:
+To use this extension you need to clone the ExoPlayer repository and depend on
-
+its modules locally. Instructions for doing this can be found in ExoPlayer's
-```
+[top level README][]. In addition, it's necessary to build the extension's
-git clone https://github.com/google/ExoPlayer.git
+native components as follows:
-```
 
 * Set the following environment variables:
 
@@ -26,8 +25,6 @@ VP9_EXT_PATH="${EXOPLAYER_ROOT}/extensions/vp9/src/main"
 
 * Download the [Android NDK][] and set its location in an environment variable:
 
-[Android NDK]: https://developer.android.com/tools/sdk/ndk/index.html
-
 ```
 NDK_PATH="<path to Android NDK>"
 ```
@@ -66,23 +63,8 @@ cd "${VP9_EXT_PATH}"/jni && \
 ${NDK_PATH}/ndk-build APP_ABI=all -j4
 ```
 
-* In your project, you can add a dependency to the VP9 Extension by using a the
+[top level README]: https://github.com/google/ExoPlayer/blob/release-v2/README.md
-  following rule:
+[Android NDK]: https://developer.android.com/tools/sdk/ndk/index.html
-
-```
-// in settings.gradle
-include ':..:ExoPlayer:library'
-include ':..:ExoPlayer:extension-vp9'
-
-// in build.gradle
-dependencies {
-    compile project(':..:ExoPlayer:library')
-    compile project(':..:ExoPlayer:extension-vp9')
-}
-```
-
-* Now, when you build your app, the VP9 extension will be built and the native
-  libraries will be packaged along with the APK.
 
 ## Notes ##
 
@@ -94,4 +76,3 @@ dependencies {
   `${VP9_EXT_PATH}/jni/libvpx` or `${VP9_EXT_PATH}/jni/libyuv` respectively. But
   please note that `generate_libvpx_android_configs.sh` and the makefiles need
   to be modified to work with arbitrary versions of libvpx and libyuv.
-