MediaPlayer_Analyze-3-native

MediaPlayer Analyze - Framework Native层

一 初始化 new MediaPlayer

1.1 jni接口

    sp<MediaPlayer> mp = new MediaPlayer(); // new C++ MediaPlayer()
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1.2 native接口

frameworks\av\media\libmedia\mediaplayer.cpp

MediaPlayer::MediaPlayer()
{
    ALOGV("constructor");
    mListener = NULL;
    mCookie = NULL;
    mStreamType = AUDIO_STREAM_MUSIC;
    mAudioAttributesParcel = NULL;
    mCurrentPosition = -1;
    mCurrentSeekMode = MediaPlayerSeekMode::SEEK_PREVIOUS_SYNC;
    mSeekPosition = -1;
    mSeekMode = MediaPlayerSeekMode::SEEK_PREVIOUS_SYNC;
    mCurrentState = MEDIA_PLAYER_IDLE;
    mPrepareSync = false;
    mPrepareStatus = NO_ERROR;
    mLoop = false;
    mLeftVolume = mRightVolume = 1.0;
    mVideoWidth = mVideoHeight = 0;
    mLockThreadId = 0;
    mAudioSessionId = (audio_session_t) AudioSystem::newAudioUniqueId(AUDIO_UNIQUE_ID_USE_SESSION);
    AudioSystem::acquireAudioSessionId(mAudioSessionId, (pid_t)-1, (uid_t)-1); // always in client.
    mSendLevel = 0;
    mRetransmitEndpointValid = false;
}
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二 设置setDataSource

2.1 jni接口

    // 调用native层接口
    status_t opStatus =
        mp->setDataSource(
                httpService,
                pathStr,
                headersVector.size() > 0? &headersVector : NULL);
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2.2 native接口

frameworks\av\media\libmedia\mediaplayer.cpp

status_t MediaPlayer::setDataSource(
        const sp<IMediaHTTPService> &httpService,
        const char *url, const KeyedVector<String8, String8> *headers)
{
    ALOGV("setDataSource(%s)", url);
    status_t err = BAD_VALUE;
    if (url != NULL) {
        // 获取MediaPlayerService
        const sp<IMediaPlayerService> service(getMediaPlayerService());
        if (service != 0) {
            // 通过MediaPlayerService调用create
            sp<IMediaPlayer> player(service->create(this, mAudioSessionId));
            if ((NO_ERROR != doSetRetransmitEndpoint(player)) ||
                (NO_ERROR != player->setDataSource(httpService, url, headers))) {
                player.clear();
            }
            // 关联新的IMediaPlayer对象player
            err = attachNewPlayer(player);
        }
    }
    return err;
}
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三 准备 prepare

1.1 jni接口

    mp->setVideoSurfaceTexture(st);

    process_media_player_call( env, thiz, mp->prepare(), "java/io/IOException", "Prepare failed." );
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1.2 native接口

frameworks\av\media\libmedia\mediaplayer.cpp

status_t MediaPlayer::setVideoSurfaceTexture(
        const sp<IGraphicBufferProducer>& bufferProducer)
{
    ALOGV("setVideoSurfaceTexture");
    Mutex::Autolock _l(mLock);
    if (mPlayer == 0) return NO_INIT;
    return mPlayer->setVideoSurfaceTexture(bufferProducer);
}

// must call with lock held
status_t MediaPlayer::prepareAsync_l()
{
    if ( (mPlayer != 0) && ( mCurrentState & (MEDIA_PLAYER_INITIALIZED | MEDIA_PLAYER_STOPPED) ) ) {
        if (mAudioAttributesParcel != NULL) {
            mPlayer->setParameter(KEY_PARAMETER_AUDIO_ATTRIBUTES, *mAudioAttributesParcel);
        } else {
            mPlayer->setAudioStreamType(mStreamType);
        }
        mCurrentState = MEDIA_PLAYER_PREPARING;
        return mPlayer->prepareAsync();
    }
    ALOGE("prepareAsync called in state %d, mPlayer(%p)", mCurrentState, mPlayer.get());
    return INVALID_OPERATION;
}
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四 开始/恢复播放 start/resume

1.1 jni接口

    process_media_player_call( env, thiz, mp->start(), NULL, NULL );
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1.2 native接口

frameworks\av\media\libmedia\mediaplayer.cpp

status_t MediaPlayer::start()
{
    ALOGV("start");

    status_t ret = NO_ERROR;
    Mutex::Autolock _l(mLock);

    mLockThreadId = getThreadId();

    if (mCurrentState & MEDIA_PLAYER_STARTED) {
        ret = NO_ERROR;
    } else if ( (mPlayer != 0) && ( mCurrentState & ( MEDIA_PLAYER_PREPARED |
                    MEDIA_PLAYER_PLAYBACK_COMPLETE | MEDIA_PLAYER_PAUSED ) ) ) {
        mPlayer->setLooping(mLoop);
        mPlayer->setVolume(mLeftVolume, mRightVolume);
        mPlayer->setAuxEffectSendLevel(mSendLevel);
        mCurrentState = MEDIA_PLAYER_STARTED;
        ret = mPlayer->start();
        if (ret != NO_ERROR) {
            mCurrentState = MEDIA_PLAYER_STATE_ERROR;
        } else {
            if (mCurrentState == MEDIA_PLAYER_PLAYBACK_COMPLETE) {
                ALOGV("playback completed immediately following start()");
            }
        }
    } else {
        ALOGE("start called in state %d, mPlayer(%p)", mCurrentState, mPlayer.get());
        ret = INVALID_OPERATION;
    }

    mLockThreadId = 0;

    return ret;
}
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五 暂停播放 pause

1.1 jni接口

    process_media_player_call( env, thiz, mp->pause(), NULL, NULL );
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1.2 native接口

frameworks\av\media\libmedia\mediaplayer.cpp

status_t MediaPlayer::pause()
{
    ALOGV("pause");
    Mutex::Autolock _l(mLock);
    if (mCurrentState & (MEDIA_PLAYER_PAUSED|MEDIA_PLAYER_PLAYBACK_COMPLETE))
        return NO_ERROR;
    if ((mPlayer != 0) && (mCurrentState & MEDIA_PLAYER_STARTED)) {
        status_t ret = mPlayer->pause();
        if (ret != NO_ERROR) {
            mCurrentState = MEDIA_PLAYER_STATE_ERROR;
        } else {
            mCurrentState = MEDIA_PLAYER_PAUSED;
        }
        return ret;
    }
    ALOGE("pause called in state %d, mPlayer(%p)", mCurrentState, mPlayer.get());
    return INVALID_OPERATION;
}
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六 停止播放 stop

1.1 jni接口

    process_media_player_call( env, thiz, mp->stop(), NULL, NULL );
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1.2 native接口

frameworks\av\media\libmedia\mediaplayer.cpp

status_t MediaPlayer::stop()
{
    ALOGV("stop");
    Mutex::Autolock _l(mLock);
    if (mCurrentState & MEDIA_PLAYER_STOPPED) return NO_ERROR;
    if ( (mPlayer != 0) && ( mCurrentState & ( MEDIA_PLAYER_STARTED | MEDIA_PLAYER_PREPARED |
                    MEDIA_PLAYER_PAUSED | MEDIA_PLAYER_PLAYBACK_COMPLETE ) ) ) {
        status_t ret = mPlayer->stop();
        if (ret != NO_ERROR) {
            mCurrentState = MEDIA_PLAYER_STATE_ERROR;
        } else {
            mCurrentState = MEDIA_PLAYER_STOPPED;
        }
        return ret;
    }
    ALOGE("stop called in state %d, mPlayer(%p)", mCurrentState, mPlayer.get());
    return INVALID_OPERATION;
}
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七 重置 reset

1.1 jni接口

    process_media_player_call( env, thiz, mp->reset(), NULL, NULL );
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1.2 native接口

frameworks\av\media\libmedia\mediaplayer.cpp

status_t MediaPlayer::reset_l()
{
    mLoop = false;
    if (mCurrentState == MEDIA_PLAYER_IDLE) return NO_ERROR;
    mPrepareSync = false;
    if (mPlayer != 0) {
        status_t ret = mPlayer->reset();
        if (ret != NO_ERROR) {
            ALOGE("reset() failed with return code (%d)", ret);
            mCurrentState = MEDIA_PLAYER_STATE_ERROR;
        } else {
            mPlayer->disconnect();
            mCurrentState = MEDIA_PLAYER_IDLE;
        }
        // setDataSource has to be called again to create a
        // new mediaplayer.
        mPlayer = 0;
        return ret;
    }
    // 重置状态
    clear_l();
    return NO_ERROR;
}
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八 释放 release

1.1 jni接口

    if (mp != NULL) {
        // this prevents native callbacks after the object is released
        mp->setListener(0);
        mp->disconnect();
    }
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1.2 native接口

frameworks\av\media\libmedia\mediaplayer.cpp

void MediaPlayer::disconnect()
{
    ALOGV("disconnect");
    sp<IMediaPlayer> p;
    {
        Mutex::Autolock _l(mLock);
        p = mPlayer;
        mPlayer.clear();
    }

    if (p != 0) {
        p->disconnect();
    }
}
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