mediapipe/docs/getting_started/android_archive_library.md

147 lines
5.9 KiB
Markdown
Raw Normal View History

---
layout: default
title: MediaPipe Android Archive
parent: Getting Started
nav_order: 7
---
# MediaPipe Android Archive
{: .no_toc }
1. TOC
{:toc}
---
***Experimental Only***
The MediaPipe Android Archive (AAR) library is a convenient way to use MediaPipe
with Android Studio and Gradle. MediaPipe doesn't publish a general AAR that can
be used by all projects. Instead, developers need to add a mediapipe_aar()
target to generate a custom AAR file for their own projects. This is necessary
in order to include specific resources such as MediaPipe calculators needed for
each project.
## Steps to build a MediaPipe AAR
1. Create a mediapipe_aar() target.
In the MediaPipe directory, create a new mediapipe_aar() target in a BUILD
file. You need to figure out what calculators are used in the graph and
provide the calculator dependencies to the mediapipe_aar(). For example, to
build an AAR for [MediaPipe Face Detection](../solutions/face_detection.md),
you can put the following code into
mediapipe/examples/android/src/java/com/google/mediapipe/apps/aar_example/BUILD.
```
load("//mediapipe/java/com/google/mediapipe:mediapipe_aar.bzl", "mediapipe_aar")
mediapipe_aar(
name = "mp_face_detection_aar",
calculators = ["//mediapipe/graphs/face_detection:mobile_calculators"],
)
```
2. Run the Bazel build command to generate the AAR.
```bash
bazel build -c opt --host_crosstool_top=@bazel_tools//tools/cpp:toolchain --fat_apk_cpu=arm64-v8a,armeabi-v7a \
//path/to/the/aar/build/file:aar_name
```
For the face detection AAR target we made in the step 1, run:
```bash
bazel build -c opt --host_crosstool_top=@bazel_tools//tools/cpp:toolchain --fat_apk_cpu=arm64-v8a,armeabi-v7a \
//mediapipe/examples/android/src/java/com/google/mediapipe/apps/aar_example:mp_face_detection_aar
# It should print:
# Target //mediapipe/examples/android/src/java/com/google/mediapipe/apps/aar_example:mp_face_detection_aar up-to-date:
# bazel-bin/mediapipe/examples/android/src/java/com/google/mediapipe/apps/aar_example/mp_face_detection_aar.aar
```
3. (Optional) Save the AAR to your preferred location.
```bash
cp bazel-bin/mediapipe/examples/android/src/java/com/google/mediapipe/apps/aar_example/mp_face_detection_aar.aar
/absolute/path/to/your/preferred/location
```
## Steps to use a MediaPipe AAR in Android Studio with Gradle
1. Start Android Studio and go to your project.
2. Copy the AAR into app/libs.
```bash
cp bazel-bin/mediapipe/examples/android/src/java/com/google/mediapipe/apps/aar_example/mp_face_detection_aar.aar
/path/to/your/app/libs/
```
![Screenshot](../images/mobile/aar_location.png)
3. Make app/src/main/assets and copy assets (graph, model, and etc) into
app/src/main/assets.
Build the MediaPipe binary graph and copy the assets into
app/src/main/assets, e.g., for the face detection graph, you need to build
and copy
[the binary graph](https://github.com/google/mediapipe/blob/master/mediapipe/examples/android/src/java/com/google/mediapipe/apps/facedetectiongpu/BUILD#L41),
[the tflite model](https://github.com/google/mediapipe/tree/master/mediapipe/models/face_detection_front.tflite),
and
[the label map](https://github.com/google/mediapipe/blob/master/mediapipe/models/face_detection_front_labelmap.txt).
```bash
bazel build -c opt mediapipe/mediapipe/graphs/face_detection:mobile_gpu_binary_graph
cp bazel-bin/mediapipe/graphs/face_detection/mobile_gpu.binarypb /path/to/your/app/src/main/assets/
cp mediapipe/models/face_detection_front.tflite /path/to/your/app/src/main/assets/
cp mediapipe/models/face_detection_front_labelmap.txt /path/to/your/app/src/main/assets/
```
![Screenshot](../images/mobile/assets_location.png)
4. Make app/src/main/jniLibs and copy OpenCV JNI libraries into
app/src/main/jniLibs.
MediaPipe depends on OpenCV, you will need to copy the precompiled OpenCV so
files into app/src/main/jniLibs. You can download the official OpenCV
Android SDK from
[here](https://github.com/opencv/opencv/releases/download/3.4.3/opencv-3.4.3-android-sdk.zip)
and run:
```bash
cp -R ~/Downloads/OpenCV-android-sdk/sdk/native/libs/arm* /path/to/your/app/src/main/jniLibs/
```
![Screenshot](../images/mobile/android_studio_opencv_location.png)
5. Modify app/build.gradle to add MediaPipe dependencies and MediaPipe AAR.
```
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar', '*.aar'])
implementation 'androidx.appcompat:appcompat:1.0.2'
implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'androidx.test.ext:junit:1.1.0'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.1'
// MediaPipe deps
implementation 'com.google.flogger:flogger:0.3.1'
implementation 'com.google.flogger:flogger-system-backend:0.3.1'
implementation 'com.google.code.findbugs:jsr305:3.0.2'
implementation 'com.google.guava:guava:27.0.1-android'
implementation 'com.google.guava:guava:27.0.1-android'
implementation 'com.google.protobuf:protobuf-java:3.11.4'
// CameraX core library
def camerax_version = "1.0.0-alpha06"
implementation "androidx.camera:camera-core:$camerax_version"
implementation "androidx.camera:camera-camera2:$camerax_version"
}
```
6. Follow our Android app examples to use MediaPipe in Android Studio for your
use case. If you are looking for an example, a face detection example can be
found
[here](https://github.com/jiuqiant/mediapipe_face_detection_aar_example) and
a multi-hand tracking example can be found
[here](https://github.com/jiuqiant/mediapipe_multi_hands_tracking_aar_example).