Android系统开发进阶-BootAnimation添加视频播放功能

对于手机用户来说，开机动画接触得比较少，因为用户可能一年也不会关开机一次。但对于 TV 设备跟盒子的用户来说，开机动画就是家常便饭了，每天都要开关机。反正都是要等待开机，看 Android logo 是看，看广告也是看，所以各厂商也就利用这个来顺便赚个广告费。Android 系统默认的开机动画只支持图片形式的动画，是不支持 mp4 等视频类型的，但我们的广告又是以视频为主的。所以我们需要给 BootAnimation 增加播放视频的功能，下面我们就来演示一下怎么实现这个功能。

1. BootAnimation 类添加 video 播放函数

BootAnimation.h

bool android();
bool movie();
//qiushao patch add start
bool video();
//qiushao patch add end

BootAnimation.cpp

//qiushao patch add start
#include <media/mediaplayer.h>
#include <media/IMediaHTTPService.h>
//qiushao patch add start

//qiushao patch add start
const char *videoPath = "/system/media/bootvideo.mp4";
bool BootAnimation::video() {
    const float MAX_FPS = 60.0f;
    const float CHECK_DELAY = ns2us(s2ns(1) / MAX_FPS);
    eglMakeCurrent(mDisplay, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
    eglDestroySurface(mDisplay, mSurface);
    sp<MediaPlayer> mp = new MediaPlayer();
    mp->reset();
    mp->setDataSource(NULL, videoPath, NULL);
    mp->setVideoSurfaceTexture(mFlingerSurface->getIGraphicBufferProducer());
    mp->prepare();
    mp->start();
    //设置音量
    mp->setVolume(1.0, 1.0);

    //等Launcher启动完成
    while(true) {
        if(exitPending()) {
            break;
        }   
        usleep(CHECK_DELAY);
        checkExit();
    }

    //等开机视频播放完成
    while (mp->isPlaying()) {
        usleep(200000);
    }
    ALOGD("bootvideo play finish");

    mp->stop();
    mp->disconnect();
    mp.clear();
    return true;
}
//qiushao patch add end
bool BootAnimation::threadLoop()
{
    //qiushao patch modify start
    if (access(videoPath, R_OK) == 0) {
        video();
    } else if (!mZipFileName.isEmpty()) {
        movie();
    } else {
        android();
    }
    //qiushao patch modify end
    ...
}

2. 添加依赖

因为我们要用到 MediaPlayer, 所以需要添加 libmedia 依赖：
Android.bp

cc_library_shared {
    name: "libbootanimation",
    defaults: ["bootanimation_defaults"],

    srcs: ["BootAnimation.cpp"],

    shared_libs: [
        "libui",
        "libhwui",
        "libEGL",
        "libGLESv1_CM",
        "libgui",
        "libtinyalsa",
        //qiushao patch add start
        "libmedia",
        //qiushao patch add end
    ],

    product_variables: {
        product_is_iot: {
            init_rc: ["iot/bootanim_iot.rc"],
        },
    },
}

3. selinux 设置

selinux 的配置都是在执行后，看报什么错误，就加什么权限，最后需要给 bootanim 服务和 mediaserver 服务添加权限，直接看 diff 吧:

qiushao@qiushao-pc:~/source/android-10/system/sepolicy$ git diff .
diff --git a/prebuilts/api/29.0/public/bootanim.te b/prebuilts/api/29.0/public/bootanim.te
index e8cb98bbc..0b1ffd3ee 100644
--- a/prebuilts/api/29.0/public/bootanim.te
+++ b/prebuilts/api/29.0/public/bootanim.te
@@ -8,6 +8,7 @@ hal_client_domain(bootanim, hal_graphics_composer)
 
 binder_use(bootanim)
 binder_call(bootanim, surfaceflinger)
+binder_call(bootanim, mediaserver)
 binder_call(bootanim, audioserver)
 
 hwbinder_use(bootanim)
@@ -23,6 +24,7 @@ allow bootanim audio_device:chr_file rw_file_perms;
 
 allow bootanim audioserver_service:service_manager find;
 allow bootanim surfaceflinger_service:service_manager find;
+allow bootanim mediaserver_service:service_manager find;
 
 # Allow access to ion memory allocation device
 allow bootanim ion_device:chr_file rw_file_perms;
diff --git a/prebuilts/api/29.0/public/mediaserver.te b/prebuilts/api/29.0/public/mediaserver.te
index 70d0a55b2..5a9d8fef0 100644
--- a/prebuilts/api/29.0/public/mediaserver.te
+++ b/prebuilts/api/29.0/public/mediaserver.te
@@ -24,6 +24,7 @@ userdebug_or_eng(`
 binder_use(mediaserver)
 binder_call(mediaserver, binderservicedomain)
 binder_call(mediaserver, appdomain)
+binder_call(mediaserver, bootanim)
 binder_service(mediaserver)
 
 allow mediaserver media_data_file:dir create_dir_perms;
diff --git a/public/bootanim.te b/public/bootanim.te
index e8cb98bbc..0b1ffd3ee 100644
--- a/public/bootanim.te
+++ b/public/bootanim.te
@@ -8,6 +8,7 @@ hal_client_domain(bootanim, hal_graphics_composer)
 
 binder_use(bootanim)
 binder_call(bootanim, surfaceflinger)
+binder_call(bootanim, mediaserver)
 binder_call(bootanim, audioserver)
 
 hwbinder_use(bootanim)
@@ -23,6 +24,7 @@ allow bootanim audio_device:chr_file rw_file_perms;
 
 allow bootanim audioserver_service:service_manager find;
 allow bootanim surfaceflinger_service:service_manager find;
+allow bootanim mediaserver_service:service_manager find;
 
 # Allow access to ion memory allocation device
 allow bootanim ion_device:chr_file rw_file_perms;
diff --git a/public/mediaserver.te b/public/mediaserver.te
index 70d0a55b2..5a9d8fef0 100644
--- a/public/mediaserver.te
+++ b/public/mediaserver.te
@@ -24,6 +24,7 @@ userdebug_or_eng(`
 binder_use(mediaserver)
 binder_call(mediaserver, binderservicedomain)
 binder_call(mediaserver, appdomain)
+binder_call(mediaserver, bootanim)
 binder_service(mediaserver)
 
 allow mediaserver media_data_file:dir create_dir_perms;
qiushao@qiushao-pc:~/source/android-10/system/sepolicy$

4. bootvideo 预置

我们把 bootvideo.mp4 视频文件放到 device/qiushao/pure/bootvideo.mp4，　我测试用的 bootvideo.mp4
然后在 pure.mk 中添加以下配置：

PRODUCT_COPY_FILES += device/qiushao/pure/bootvideo.mp4:system/media/bootvideo.mp4

5. 编译验证

以上就完成了 BootAnimation 播放视频的功能，其实也很简单，就是调用一下 MediaPlayer 的 c++ 接口而已。音量设置也是可以的。
我们编译验证一下，图像声音都是正常的。