Android对接实现内网无纸化会议|智慧教室|实时同屏功能

背景

本文主要讲的是基于Android平台实现RTMP的技术方案设计，基础架构图如下：

组网注意事项

1. 组网：无线组网，需要好的AP模块才能撑得住大的并发流量，推送端到AP，最好是有线网链接；

2. 服务器部署：SRS或NGINX，服务器可以和Windows平台的教师机部署在一台机器；

3. 教师端：如教师有移动的PAD，可以直接推到RTMP服务器，然后共享出去；

4. 学生端：直接拉取服务端的RTMP流播放即可；

5. 教师和学生互动：学生端如需作为示范案例，屏幕数据共享给其他同学，只需请求同屏，数据反推到RTMP服务器，其他学生查看即可。

6. 扩展监控：如果需要更进一步的技术方案，如教师端想监控学生端的屏幕情况，可以有两种方案，如学生端直接推RTMP过来，或者，学生端启动内置RTSP服务，教师端想看的时候，随时看即可（亦可轮询播放）。

Android端对接

推送分辨率如何设定或缩放？

Android设备，特别是高分屏，拿到的视频原始宽高非常大，如果推原始分辨率，编码和上行压力大，所以，一般建议，适当缩放，比如宽高缩放至2/3，缩放一般建议等比例缩放，缩放宽高建议16字节对齐。

    private void createScreenEnvironment() {sreenWindowWidth = mWindowManager.getDefaultDisplay().getWidth();screenWindowHeight = mWindowManager.getDefaultDisplay().getHeight();Log.i(TAG, "screenWindowWidth: " + sreenWindowWidth + ",screenWindowHeight: "+ screenWindowHeight);if (sreenWindowWidth > 800){if (screenResolution == SCREEN_RESOLUTION_STANDARD){scale_rate = SCALE_RATE_HALF;sreenWindowWidth = align(sreenWindowWidth / 2, 16);screenWindowHeight = align(screenWindowHeight / 2, 16);}else if(screenResolution == SCREEN_RESOLUTION_LOW){scale_rate = SCALE_RATE_TWO_FIFTHS;sreenWindowWidth = align(sreenWindowWidth * 2 / 5, 16);}}Log.i(TAG, "After adjust mWindowWidth: " + sreenWindowWidth + ", mWindowHeight: " + screenWindowHeight);int pf = mWindowManager.getDefaultDisplay().getPixelFormat();Log.i(TAG, "display format:" + pf);DisplayMetrics displayMetrics = new DisplayMetrics();mWindowManager.getDefaultDisplay().getMetrics(displayMetrics);mScreenDensity = displayMetrics.densityDpi;mImageReader = ImageReader.newInstance(sreenWindowWidth,screenWindowHeight, 0x1, 6);mMediaProjectionManager = (MediaProjectionManager) getSystemService(Context.MEDIA_PROJECTION_SERVICE);}

横竖屏自动适配

横竖屏状态下，采集的屏幕宽高不一样，如果横竖屏切换，这个时候，需要考虑到横竖屏适配问题，确保比如竖屏状态下，切换到横屏时，推拉流两端可以自动适配，横竖屏自动适配，编码器需要重启，拉流端，需要能自动适配宽高变化，自动播放。

    public void onConfigurationChanged(Configuration newConfig) {try {super.onConfigurationChanged(newConfig);if (this.getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE) {Log.i(TAG, "onConfigurationChanged cur: LANDSCAPE");} else if (this.getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT) {Log.i(TAG, "onConfigurationChanged cur: PORTRAIT");}if(isPushingRtmp || isRecording || isRTSPPublisherRunning){stopScreenCapture();clearAllImages();createScreenEnvironment();setupVirtualDisplay();}} catch (Exception ex) {}}

补帧策略

好多人不理解为什么要补帧，实际上，屏幕采集的时候，屏幕不动的话，不会一直有数据下去，这个时候，比较好的做法是，保存最后一帧数据，设定一定的补帧间隔，确保不会因为帧间距太大，导致播放端几秒都收不到数据，当然，如果服务器可以缓存GOP，这个问题迎刃而解。

异常网络处理、事件回调机制

回答：如果是走RTMP，网络抖动或者其他网络异常，需要有好重连机制和状态回馈机制。

    class EventHandeV2 implements NTSmartEventCallbackV2 {@Overridepublic void onNTSmartEventCallbackV2(long handle, int id, long param1, long param2, String param3, String param4, Object param5) {Log.i(TAG, "EventHandeV2: handle=" + handle + " id:" + id);String publisher_event = "";switch (id) {case NTSmartEventID.EVENT_DANIULIVE_ERC_PUBLISHER_STARTED:publisher_event = "开始..";break;case NTSmartEventID.EVENT_DANIULIVE_ERC_PUBLISHER_CONNECTING:publisher_event = "连接中..";break;case NTSmartEventID.EVENT_DANIULIVE_ERC_PUBLISHER_CONNECTION_FAILED:publisher_event = "连接失败..";break;case NTSmartEventID.EVENT_DANIULIVE_ERC_PUBLISHER_CONNECTED:publisher_event = "连接成功..";break;case NTSmartEventID.EVENT_DANIULIVE_ERC_PUBLISHER_DISCONNECTED:publisher_event = "连接断开..";break;case NTSmartEventID.EVENT_DANIULIVE_ERC_PUBLISHER_STOP:publisher_event = "关闭..";break;case NTSmartEventID.EVENT_DANIULIVE_ERC_PUBLISHER_RECORDER_START_NEW_FILE:publisher_event = "开始一个新的录像文件 : " + param3;break;case NTSmartEventID.EVENT_DANIULIVE_ERC_PUBLISHER_ONE_RECORDER_FILE_FINISHED:publisher_event = "已生成一个录像文件 : " + param3;break;case NTSmartEventID.EVENT_DANIULIVE_ERC_PUBLISHER_SEND_DELAY:publisher_event = "发送时延: " + param1 + " 帧数:" + param2;break;case NTSmartEventID.EVENT_DANIULIVE_ERC_PUBLISHER_CAPTURE_IMAGE:publisher_event = "快照: " + param1 + " 路径：" + param3;if (param1 == 0) {publisher_event = publisher_event + "截取快照成功..";} else {publisher_event = publisher_event + "截取快照失败..";}break;case NTSmartEventID.EVENT_DANIULIVE_ERC_PUBLISHER_RTSP_URL:publisher_event = "RTSP服务URL: " + param3;break;case NTSmartEventID.EVENT_DANIULIVE_ERC_PUSH_RTSP_SERVER_RESPONSE_STATUS_CODE:publisher_event ="RTSP status code received, codeID: " + param1 + ", RTSP URL: " + param3;break;case NTSmartEventID.EVENT_DANIULIVE_ERC_PUSH_RTSP_SERVER_NOT_SUPPORT:publisher_event ="服务器不支持RTSP推送, 推送的RTSP URL: " + param3;break;}String str = "当前回调状态：" + publisher_event;Log.i(TAG, str);Message message = new Message();message.what = PUBLISHER_EVENT_MSG;message.obj = publisher_event;handler.sendMessage(message);}}

部分屏幕数据采集

回答：我们遇到的好多场景下，教室端，会拿出来3/4的区域用来投递给学生看，1/4的区域，用来做一些指令等操作，这个时候，就需要考虑屏幕区域裁剪：

 /*** 投递裁剪过的RGBA数据** @param data: RGBA data** @param rowStride: stride information** @param width: width** @param height: height** @param clipedLeft: 左;  clipedTop: 上; clipedwidth: 裁剪后的宽; clipedHeight: 裁剪后的高; 确保传下去裁剪后的宽、高均为偶数** @return {0} if successful*/public native int SmartPublisherOnCaptureVideoClipedRGBAData(long handle,  ByteBuffer data, int rowStride, int width, int height, int clipedLeft, int clipedTop, int clipedWidth, int clipedHeight);

文字、图片水印

好多场景下，同屏者会把公司logo，和一定的文字信息展示在推送端，这个时候，需要考虑到文字和图片水印问题：

   /*** Set Text water-mark(设置文字水印)* * @param fontSize: it should be "MEDIUM", "SMALL", "BIG"* * @param waterPostion: it should be "TOPLEFT", "TOPRIGHT", "BOTTOMLEFT", "BOTTOMRIGHT".* * @param xPading, yPading: the distance of the original picture.* * <pre> The interface is only used for setting font water-mark when publishing stream. </pre>  * * @return {0} if successful*/public native int SmartPublisherSetTextWatermark(long handle, String waterText, int isAppendTime, int fontSize, int waterPostion, int xPading, int yPading);/*** Set Text water-mark font file name(设置文字水印字体路径)** @param fontFileName:  font full file name, e.g: /system/fonts/DroidSansFallback.ttf** @return {0} if successful*/public native int SmartPublisherSetTextWatermarkFontFileName(long handle, String fontFileName);/*** Set picture water-mark(设置png图片水印)*                                            * @param picPath: the picture working path, e.g: /sdcard/logo.png* * @param waterPostion: it should be "TOPLEFT", "TOPRIGHT", "BOTTOMLEFT", "BOTTOMRIGHT".* * @param picWidth, picHeight: picture width & height* * @param xPading, yPading: the distance of the original picture.* * <pre> The interface is only used for setting picture(logo) water-mark when publishing stream, with "*.png" format </pre>  * * @return {0} if successful*/public native int SmartPublisherSetPictureWatermark(long handle, String picPath, int waterPostion, int picWidth, int picHeight, int xPading, int yPading);

屏幕权限获取|数据采集

采集推送之前，需要获取屏幕权限，拿到屏幕数据后，调用SDK接口，完成推送或录像操作即可：

   @TargetApi(Build.VERSION_CODES.LOLLIPOP)private boolean startScreenCapture() {Log.i(TAG, "startScreenCapture..");setupMediaProjection();setupVirtualDisplay();return true;}private int align(int d, int a) {return (((d) + (a - 1)) & ~(a - 1));}@SuppressWarnings("deprecation")@SuppressLint("NewApi")private void createScreenEnvironment() {sreenWindowWidth = mWindowManager.getDefaultDisplay().getWidth();screenWindowHeight = mWindowManager.getDefaultDisplay().getHeight();Log.i(TAG, "screenWindowWidth: " + sreenWindowWidth + ",screenWindowHeight: "+ screenWindowHeight);if (sreenWindowWidth > 800){if (screenResolution == SCREEN_RESOLUTION_STANDARD){scale_rate = SCALE_RATE_HALF;sreenWindowWidth = align(sreenWindowWidth / 2, 16);screenWindowHeight = align(screenWindowHeight / 2, 16);}else if(screenResolution == SCREEN_RESOLUTION_LOW){scale_rate = SCALE_RATE_TWO_FIFTHS;sreenWindowWidth = align(sreenWindowWidth * 2 / 5, 16);screenWindowHeight = align(screenWindowHeight * 2 / 5, 16);}}Log.i(TAG, "After adjust mWindowWidth: " + sreenWindowWidth + ", mWindowHeight: " + screenWindowHeight);int pf = mWindowManager.getDefaultDisplay().getPixelFormat();Log.i(TAG, "display format:" + pf);DisplayMetrics displayMetrics = new DisplayMetrics();mWindowManager.getDefaultDisplay().getMetrics(displayMetrics);mScreenDensity = displayMetrics.densityDpi;mImageReader = ImageReader.newInstance(sreenWindowWidth,screenWindowHeight, 0x1, 6);mMediaProjectionManager = (MediaProjectionManager) getSystemService(Context.MEDIA_PROJECTION_SERVICE);}@SuppressLint("NewApi")private void setupMediaProjection() {mMediaProjection = mMediaProjectionManager.getMediaProjection(MainActivity.mResultCode, MainActivity.mResultData);}@SuppressLint("NewApi")private void setupVirtualDisplay() {mVirtualDisplay = mMediaProjection.createVirtualDisplay("ScreenCapture", sreenWindowWidth, screenWindowHeight,mScreenDensity,DisplayManager.VIRTUAL_DISPLAY_FLAG_AUTO_MIRROR,mImageReader.getSurface(), null, null);mImageReader.setOnImageAvailableListener(new ImageReader.OnImageAvailableListener() {@Overridepublic void onImageAvailable(ImageReader reader) {Image image = mImageReader.acquireLatestImage();if (image != null) {processScreenImage(image);//image.close();}}}, null);}private void startRecorderScreen() {Log.i(TAG, "start recorder screen..");if (startScreenCapture()) {new Thread() {@Overridepublic void run() {Log.i(TAG, "start record..");}}.start();}}private ByteBuffer deepCopy(ByteBuffer source) {int sourceP = source.position();int sourceL = source.limit();ByteBuffer target = ByteBuffer.allocateDirect(source.remaining());target.put(source);target.flip();source.position(sourceP);source.limit(sourceL);return target;}/*** Process image data as desired.*/@SuppressLint("NewApi")private void processScreenImage(Image image) {if(!isPushingRtmp && !isRecording &&!isRTSPPublisherRunning){image.close();return;}/*final Image.Plane[] planes = image.getPlanes();width_ = image.getWidth();height_ = image.getHeight();row_stride_ = planes[0].getRowStride();ByteBuffer buf = deepCopy(planes[0].getBuffer());*/// Log.i("OnScreenImage", "new image");pushImage(image);}@SuppressLint("NewApi")private void stopScreenCapture() {if (mVirtualDisplay != null) {mVirtualDisplay.release();mVirtualDisplay = null;}}

基础初始化

   private void InitAndSetConfig() {//开始要不要采集音频或视频，请自行设置publisherHandle = libPublisher.SmartPublisherOpen(this.getApplicationContext(),audio_opt, video_opt, sreenWindowWidth,screenWindowHeight);if ( publisherHandle == 0 ){return;}Log.i(TAG, "publisherHandle=" + publisherHandle);libPublisher.SetSmartPublisherEventCallbackV2(publisherHandle, new EventHandeV2());if(videoEncodeType == 1){int h264HWKbps = setHardwareEncoderKbps(true, sreenWindowWidth,screenWindowHeight);Log.i(TAG, "h264HWKbps: " + h264HWKbps);int isSupportH264HWEncoder = libPublisher.SetSmartPublisherVideoHWEncoder(publisherHandle, h264HWKbps);if (isSupportH264HWEncoder == 0) {Log.i(TAG, "Great, it supports h.264 hardware encoder!");}}else if (videoEncodeType == 2){int hevcHWKbps = setHardwareEncoderKbps(false, sreenWindowWidth,screenWindowHeight);Log.i(TAG, "hevcHWKbps: " + hevcHWKbps);int isSupportHevcHWEncoder = libPublisher.SetSmartPublisherVideoHevcHWEncoder(publisherHandle, hevcHWKbps);if (isSupportHevcHWEncoder == 0) {Log.i(TAG, "Great, it supports hevc hardware encoder!");}}if(is_sw_vbr_mode){int is_enable_vbr = 1;int video_quality = CalVideoQuality(sreenWindowWidth,screenWindowHeight, true);int vbr_max_bitrate = CalVbrMaxKBitRate(sreenWindowWidth,screenWindowHeight);libPublisher.SmartPublisherSetSwVBRMode(publisherHandle, is_enable_vbr, video_quality, vbr_max_bitrate);}//音频相关可以参考SmartPublisher工程/*if (!is_speex){// set AAC encoderlibPublisher.SmartPublisherSetAudioCodecType(publisherHandle, 1);}else{// set Speex encoderlibPublisher.SmartPublisherSetAudioCodecType(publisherHandle, 2);libPublisher.SmartPublisherSetSpeexEncoderQuality(publisherHandle, 8);}libPublisher.SmartPublisherSetNoiseSuppression(publisherHandle, is_noise_suppression ? 1: 0);libPublisher.SmartPublisherSetAGC(publisherHandle, is_agc ? 1 : 0);*/// libPublisher.SmartPublisherSetClippingMode(publisherHandle, 0);//libPublisher.SmartPublisherSetSWVideoEncoderProfile(publisherHandle, sw_video_encoder_profile);//libPublisher.SmartPublisherSetSWVideoEncoderSpeed(publisherHandle, sw_video_encoder_speed);// libPublisher.SetRtmpPublishingType(publisherHandle, 0);libPublisher.SmartPublisherSetFPS(publisherHandle, 18);    //帧率可调libPublisher.SmartPublisherSetGopInterval(publisherHandle, 18*3);//libPublisher.SmartPublisherSetSWVideoBitRate(publisherHandle, 1200, 2400); //针对软编码有效，一般最大码率是平均码率的二倍libPublisher.SmartPublisherSetSWVideoEncoderSpeed(publisherHandle, 3);//libPublisher.SmartPublisherSaveImageFlag(publisherHandle, 1);}

准备推送|录像|启动RTSP服务

    @SuppressWarnings("deprecation")@Overridepublic void onStart(Intent intent, int startId) {// TODO Auto-generated method stubsuper.onStart(intent, startId);Log.i(TAG, "onStart++");if (libPublisher == null)return;clearAllImages();screenResolution = intent.getExtras().getInt("SCREENRESOLUTION");videoEncodeType = intent.getExtras().getInt("VIDEOENCODETYPE");push_type = intent.getExtras().getInt("PUSHTYPE");Log.i(TAG, "push_type: " + push_type);mWindowManager = (WindowManager) getSystemService(Service.WINDOW_SERVICE);// 窗口管理者createScreenEnvironment();startRecorderScreen();//如果同时推送和录像，设置一次就可以InitAndSetConfig();if ( publisherHandle == 0 ){stopScreenCapture();return;}if(push_type == PUSH_TYPE_RTMP){String publishURL = intent.getStringExtra("PUBLISHURL");Log.i(TAG, "publishURL: " + publishURL);if (libPublisher.SmartPublisherSetURL(publisherHandle, publishURL) != 0) {stopScreenCapture();Log.e(TAG, "Failed to set publish stream URL..");if (publisherHandle != 0) {if (libPublisher != null) {libPublisher.SmartPublisherClose(publisherHandle);publisherHandle = 0;}}return;}}//启动传递数据线程post_data_thread = new Thread(new DataRunnable());Log.i(TAG, "new post_data_thread..");is_post_data_thread_alive = true;post_data_thread.start();//录像相关++is_need_local_recorder = intent.getExtras().getBoolean("RECORDER");if(is_need_local_recorder){ConfigRecorderParam();int startRet = libPublisher.SmartPublisherStartRecorder(publisherHandle);if( startRet != 0 ){isRecording = false;Log.e(TAG, "Failed to start recorder..");}else{isRecording = true;}}//录像相关——if(push_type == PUSH_TYPE_RTMP){Log.i(TAG, "RTMP Pusher mode..");//推流相关++int startRet = libPublisher.SmartPublisherStartPublisher(publisherHandle);if (startRet != 0) {isPushingRtmp = false;Log.e(TAG, "Failed to start push rtmp stream..");return;}else{isPushingRtmp = true;}//推流相关--}else if(push_type == PUSH_TYPE_RTSP){Log.i(TAG, "RTSP Internal Server mode..");rtsp_handle_ = libPublisher.OpenRtspServer(0);if (rtsp_handle_ == 0) {Log.e(TAG, "创建rtsp server实例失败! 请检查SDK有效性");} else {int port = 8554;if (libPublisher.SetRtspServerPort(rtsp_handle_, port) != 0) {libPublisher.CloseRtspServer(rtsp_handle_);rtsp_handle_ = 0;Log.e(TAG, "创建rtsp server端口失败! 请检查端口是否重复或者端口不在范围内!");}//String user_name = "admin";//String password = "12345";//libPublisher.SetRtspServerUserNamePassword(rtsp_handle_, user_name, password);if (libPublisher.StartRtspServer(rtsp_handle_, 0) == 0) {Log.i(TAG, "启动rtsp server 成功!");} else {libPublisher.CloseRtspServer(rtsp_handle_);rtsp_handle_ = 0;Log.e(TAG, "启动rtsp server失败! 请检查设置的端口是否被占用!");return;}isRTSPServiceRunning = true;}if(isRTSPServiceRunning){Log.i(TAG, "onClick start rtsp publisher..");String rtsp_stream_name = "stream1";libPublisher.SetRtspStreamName(publisherHandle, rtsp_stream_name);libPublisher.ClearRtspStreamServer(publisherHandle);libPublisher.AddRtspStreamServer(publisherHandle, rtsp_handle_, 0);if (libPublisher.StartRtspStream(publisherHandle, 0) != 0) {Log.e(TAG, "调用发布rtsp流接口失败!");return;}isRTSPPublisherRunning = true;}}//如果同时推送和录像，Audio启动一次就可以了CheckInitAudioRecorder();Log.i(TAG, "onStart--");}private void stopPush() {if(!isPushingRtmp){return;}if (!isRecording && !isRTSPPublisherRunning) {if (audioRecord_ != null) {Log.i(TAG, "stopPush, call audioRecord_.StopRecording..");audioRecord_.Stop();if (audioRecordCallback_ != null) {audioRecord_.RemoveCallback(audioRecordCallback_);audioRecordCallback_ = null;}audioRecord_ = null;}}if (libPublisher != null) {libPublisher.SmartPublisherStopPublisher(publisherHandle);}if (!isRecording && !isRTSPPublisherRunning) {if (publisherHandle != 0) {if (libPublisher != null) {libPublisher.SmartPublisherClose(publisherHandle);publisherHandle = 0;}}}}

停止推送|录像|RTSP服务

   private void stopRecorder() {if(!isRecording){return;}if (!isPushingRtmp && !isRTSPPublisherRunning) {if (audioRecord_ != null) {Log.i(TAG, "stopRecorder, call audioRecord_.StopRecording..");audioRecord_.Stop();if (audioRecordCallback_ != null) {audioRecord_.RemoveCallback(audioRecordCallback_);audioRecordCallback_ = null;}audioRecord_ = null;}}if (libPublisher != null) {libPublisher.SmartPublisherStopRecorder(publisherHandle);}if (!isPushingRtmp && !isRTSPPublisherRunning) {if (publisherHandle != 0) {if (libPublisher != null) {libPublisher.SmartPublisherClose(publisherHandle);publisherHandle = 0;}}}}//停止发布RTSP流private void stopRtspPublisher() {if(!isRTSPPublisherRunning){return;}if (!isPushingRtmp && !isRecording) {if (audioRecord_ != null) {Log.i(TAG, "stopRtspPublisher, call audioRecord_.StopRecording..");audioRecord_.Stop();if (audioRecordCallback_ != null) {audioRecord_.RemoveCallback(audioRecordCallback_);audioRecordCallback_ = null;}audioRecord_ = null;}}if (libPublisher != null) {libPublisher.StopRtspStream(publisherHandle);}if (!isPushingRtmp && !isRecording) {if (publisherHandle != 0) {if (libPublisher != null) {libPublisher.SmartPublisherClose(publisherHandle);publisherHandle = 0;}}}}//停止RTSP服务private void stopRtspService() {if(!isRTSPServiceRunning){return;}if (libPublisher != null && rtsp_handle_ != 0) {libPublisher.StopRtspServer(rtsp_handle_);libPublisher.CloseRtspServer(rtsp_handle_);rtsp_handle_ = 0;}}

感兴趣的开发者可酌情参考。