android MediaPlayer surface分析

简单记录一下mediaplayer Surface和Render的过程

void setSurface(Surface surface) ------MediaPlayer.java

    void android_media_MediaPlayer_setVideoSurface ---- android_media_MediaPlayer.cpp

    sp<IGraphicBufferProducer> new_st;
    if (jsurface) {
        sp<Surface> surface(android_view_Surface_getSurface(env, jsurface));
        if (surface != NULL) {
            new_st = surface->getIGraphicBufferProducer();
            if (new_st == NULL) {
                jniThrowException(env, "java/lang/IllegalArgumentException",
                    "The surface does not have a binding SurfaceTexture!");
                return;
            }
            new_st->incStrong((void*)decVideoSurfaceRef);
        } else {
            jniThrowException(env, "java/lang/IllegalArgumentException",
                    "The surface has been released");
            return;
        }

329    }

    env->SetLongField(thiz, fields.surface_texture, (jlong)new_st.get());

    // This will fail if the media player has not been initialized yet. This
    // can be the case if setDisplay() on MediaPlayer.java has been called
    // before setDataSource(). The redundant call to setVideoSurfaceTexture()
    // in prepare/prepareAsync covers for this case.
    mp->setVideoSurfaceTexture(new_st);

        setVideoSurfaceText    MediaPlayer.cpp-->MediaPlayerService.cpp--->StageFrightPlayer.cpp

              setSurfaceTexture  AwesomePlayer.cpp

status_t AwesomePlayer::setSurfaceTexture(const sp<IGraphicBufferProducer> &bufferProducer) {
    Mutex::Autolock autoLock(mLock);

    status_t err;
    if (bufferProducer != NULL) {
        err = setNativeWindow_l(new Surface(bufferProducer));
    } else {
        err = setNativeWindow_l(NULL);
    }

    return err;
}

status_t AwesomePlayer::setNativeWindow_l(const sp<ANativeWindow> &native) {
    mNativeWindow = native;

到这里，把java层Surface赋给mNativeWindow。

接下来简单看一下mNativeWindow和Render的关系

mNativeWindow非空，则初始化Render

void AwesomePlayer::onVideoEvent() {

.....

    if ((mNativeWindow != NULL)
            && (mVideoRendererIsPreview || mVideoRenderer == NULL)) {
        mVideoRendererIsPreview = false;

        initRenderer_l();
    }

    if (mVideoRenderer != NULL) {
        mSinceLastDropped++;
        mVideoBuffer->meta_data()->setInt64(kKeyTime, looperTimeUs - latenessUs);

        mVideoRenderer->render(mVideoBuffer);
        if (!mVideoRenderingStarted) {
            mVideoRenderingStarted = true;
            notifyListener_l(MEDIA_INFO, MEDIA_INFO_RENDERING_START);
        }

        if (mFlags & PLAYING) {
            notifyIfMediaStarted_l();
        }
    }

.....

void AwesomePlayer::initRenderer_l() {
    ATRACE_CALL();

    if (mNativeWindow == NULL) {
        return;
    }

......

    mVideoRenderer.clear();

    // Must ensure that mVideoRenderer's destructor is actually executed
    // before creating a new one.
    IPCThreadState::self()->flushCommands();

    // Even if set scaling mode fails, we will continue anyway
    setVideoScalingMode_l(mVideoScalingMode);
    if (USE_SURFACE_ALLOC
            && !strncmp(component, "OMX.", 4)
            && strncmp(component, "OMX.google.", 11)) {
        // Hardware decoders avoid the CPU color conversion by decoding
        // directly to ANativeBuffers, so we must use a renderer that
        // just pushes those buffers to the ANativeWindow.
        mVideoRenderer =
            new AwesomeNativeWindowRenderer(mNativeWindow, rotationDegrees);
    } else {
        // Other decoders are instantiated locally and as a consequence
        // allocate their buffers in local address space.  This renderer
        // then performs a color conversion and copy to get the data
        // into the ANativeBuffer.
        sp<AMessage> format;
        convertMetaDataToMessage(meta, &format);
        mVideoRenderer = new AwesomeLocalRenderer(mNativeWindow, format);
    }

struct AwesomeLocalRenderer : public AwesomeRenderer {
    AwesomeLocalRenderer(
            const sp<ANativeWindow> &nativeWindow, const sp<AMessage> &format)
        : mFormat(format),
          mTarget(new SoftwareRenderer(nativeWindow)) {
    }

    virtual void render(MediaBuffer *buffer) {
        int64_t timeUs;
        CHECK(buffer->meta_data()->findInt64(kKeyTime, &timeUs));

        render((const uint8_t *)buffer->data() + buffer->range_offset(),
               buffer->range_length(), timeUs, timeUs * 1000);
    }

    void render(const void *data, size_t size, int64_t mediaTimeUs, nsecs_t renderTimeNs) {
        (void)mTarget->render(data, size, mediaTimeUs, renderTimeNs, NULL, mFormat);
    }

protected:
    virtual ~AwesomeLocalRenderer() {
        delete mTarget;
        mTarget = NULL;
    }

private:
    sp<AMessage> mFormat;
    SoftwareRenderer *mTarget;

    AwesomeLocalRenderer(const AwesomeLocalRenderer &);
    AwesomeLocalRenderer &operator=(const AwesomeLocalRenderer &);;
};

struct AwesomeNativeWindowRenderer : public AwesomeRenderer {
    AwesomeNativeWindowRenderer(
            const sp<ANativeWindow> &nativeWindow,
            int32_t rotationDegrees)
        : mNativeWindow(nativeWindow) {
        applyRotation(rotationDegrees);
    }

    virtual void render(MediaBuffer *buffer) {
        ATRACE_CALL();
        int64_t timeUs;
        CHECK(buffer->meta_data()->findInt64(kKeyTime, &timeUs));
        native_window_set_buffers_timestamp(mNativeWindow.get(), timeUs * 1000);
        status_t err = mNativeWindow->queueBuffer(
                mNativeWindow.get(), buffer->graphicBuffer().get(), -1);
        if (err != 0) {
            ALOGE("queueBuffer failed with error %s (%d)", strerror(-err),
                    -err);
            return;
        }

        sp<MetaData> metaData = buffer->meta_data();
        metaData->setInt32(kKeyRendered, 1);
    }

protected:
    virtual ~AwesomeNativeWindowRenderer() {}

private:
    sp<ANativeWindow> mNativeWindow;

    void applyRotation(int32_t rotationDegrees) {
        uint32_t transform;
        switch (rotationDegrees) {
            case 0: transform = 0; break;
            case 90: transform = HAL_TRANSFORM_ROT_90; break;
            case 180: transform = HAL_TRANSFORM_ROT_180; break;
            case 270: transform = HAL_TRANSFORM_ROT_270; break;
            default: transform = 0; break;
        }

        if (transform) {
            CHECK_EQ(0, native_window_set_buffers_transform(
                        mNativeWindow.get(), transform));
        }
    }

    AwesomeNativeWindowRenderer(const AwesomeNativeWindowRenderer &);
    AwesomeNativeWindowRenderer &operator=(
            const AwesomeNativeWindowRenderer &);
};

最好数据送往ANativeWindow，接下来进入SurfaceFlinger已经android graphis系统。

这部分架构的简介 https://source.android.com/devices/graphics/architecture.html

来源：CSDN

作者：sujia13

链接：https://blog.csdn.net/sujia13/article/details/51568776