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 {
@Override
public 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.
*
* The interface is only used for setting font water-mark when publishing stream.
*
* @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.
*
* The interface is only used for setting picture(logo) water-mark when publishing stream, with "*.png" format
*
* @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() {
@Override
public 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() {
@Override
public 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 encoder
libPublisher.SmartPublisherSetAudioCodecType(publisherHandle, 1);
}
else
{
// set Speex encoder
libPublisher.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")
@Override
public void onStart(Intent intent, int startId) {
// TODO Auto-generated method stub
super.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。
