Android音视频开发MediaFrameWork框架源码解析

class BnMediaPlayer: public BnInterface
{
public:
    virtual status_t    onTransact( uint32_t code,
                                    const Parcel& data,
                                    Parcel* reply,
                                    uint32_t flags = 0);
};
​

status_t MediaPlayer::setDataSource(
        const char *url, const KeyedVector *headers)
{
    LOGV("setDataSource(%s)", url);
    status_t err = BAD_VALUE;
    if (url != NULL) {
        const sp& service(getMediaPlayerService());
        if (service != 0) {
            sp player(
                    service->create(getpid(), this, url, headers));
            err = setDataSource(player);
        }
    }
    return err;
}
​

sp MediaPlayerService::create(
​
        pid_t pid, const sp& client, const char* url,
        const KeyedVector *headers)
{
    int32_t connId = Android_atomic_inc(&mNextConnId);
    sp c = new Client(this, pid, connId, client);
    LOGV("Create new client(%d) from pid %d, url=%s, connId=%d", connId, pid, url, connId);
    if (NO_ERROR != c->setDataSource(url, headers))
    {
        c.clear();
        return c;
    }
    wp w = c;
    Mutex::Autolock lock(mLock);
    mClients.add(w);
    return c;
}

class IMediaPlayerClient: public IInterface
{
public:
    DECLARE_META_INTERFACE(MediaPlayerClient);​
    virtual void notify(int msg, int ext1, int ext2) = 0;
};

`static` `void` `android_media_MediaPlayer_native_setup(
    JNIEnv *env, jobject thiz, jobject weak_this
    )``
    {
        ``  ``
    LOGV(``"native_setup"``);
        ``  ``sp mp = ``new` `MediaPlayer();
        ``  ``
        if` `(mp == NULL) {
        ``    ``
        jniThrowException(
            env, ``"java/lang/RuntimeException"``, 
            ``"Out of memory"``);
            ``    
            ``return``;
            ``  ``
            
        }
            ` `  ``
            // create new listener and give it to MediaPlayer
            ``  ``
            sp listener = ``new` `JNIMediaPlayerListener(
                env, thiz, weak_this);
                ``  ``
                mp->setListener(listener);
                ` `  ``
                // Stow our new c++ MediaPlayer in an opaque field in the Java object.
                ``  ``
                setMediaPlayer(env, thiz, mp);
                ``
        
    }
        `

status_t MediaPlayer::start()
{
    LOGV("start");
    Mutex::Autolock _l(mLock);
    if (mCurrentState & MEDIA_PLAYER_STARTED)
        return NO_ERROR;
    if ( (mPlayer != 0) && ( mCurrentState & ( MEDIA_PLAYER_PREPARED |
                    MEDIA_PLAYER_PLAYBACK_COMPLETE | MEDIA_PLAYER_PAUSED ) ) ) {
        mPlayer->setLooping(mLoop);
        mPlayer->setVolume(mLeftVolume, mRightVolume);
        mCurrentState = MEDIA_PLAYER_STARTED;
        status_t ret = mPlayer->start();
        if (ret != NO_ERROR) {
            mCurrentState = MEDIA_PLAYER_STATE_ERROR;
        } else {
            if (mCurrentState == MEDIA_PLAYER_PLAYBACK_COMPLETE) {
                LOGV("playback completed immediately following start()");
            }
        }
        return ret;
    }
    LOGE("start called in state %d", mCurrentState);
    return INVALID_OPERATION;
}

class IMediaPlayer: public IInterface
{
public:
    DECLARE_META_INTERFACE(MediaPlayer);
    virtual void            disconnect() = 0;
    virtual status_t        setVideoSurface(const sp<ISurface>& surface) = 0;
    virtual status_t        prepareAsync() = 0;
    virtual status_t        start() = 0;
    virtual status_t        stop() = 0;
    virtual status_t        pause() = 0;
    virtual status_t        isPlaying(bool* state) = 0;
    virtual status_t        seekTo(int msec) = 0;
    virtual status_t        getCurrentPosition(int* msec) = 0;
    virtual status_t        getDuration(int* msec) = 0;
    virtual status_t        reset() = 0;
    virtual status_t        setAudiOStreamType(int type) = 0;
    virtual status_t        setLooping(int loop) = 0;
    virtual status_t        setVolume(float leftVolume, float rightVolume) = 0;
    virtual status_t        invoke(const Parcel& request, Parcel *reply) = 0;
    virtual status_t        setMetadataFilter(const Parcel& filter) = 0;
    virtual status_t        getMetadata(bool update_only,
                                        bool apply_filter,
                                        Parcel *metadata) = 0;
};

virtual sp<IMediaRecorder>  createMediaRecorder(pid_t pid);
void    removeMediaRecorderClient(wp<MediaRecorderClient> client);
virtual sp<IMediaMetadataRetriever> createMetadataRetriever(pid_t pid);
// House keeping for media player clients
virtual sp<IMediaPlayer>    create(pid_t pid, const sp<IMediaPlayerClient>& client, const char* url);
virtual sp<IMediaPlayer>    create(pid_t pid, const sp<IMediaPlayerClient>& client, int fd, int64_t offset, int64_t length);