Overview

Publishing from camera refers to the process of collecting video and audio data from the mobile phone’s camera and mic, encoding the data, and publishing it to cloud-based live streaming platforms. Tencent Cloud’s LiteAVSDK provides the camera publishing capability via V2TXLivePusher.

Notes

Testing on real devices: The SDK uses a lot of audio and video APIs of the Android system, most of which cannot be used on emulators. Therefore, we recommend that you test your project on a real device.

Sample Code

Note：

In addition to the above sample code, regarding frequently asked questions among developers, Tencent Cloud offers a straightforward API example project, which you can use to quickly learn how to use different APIs.

• iOS: MLVB-API-Example
• Android: MLVB-API-Example

Integration

1. Download the SDK

Download the SDK ZIP file and follow the instructions in SDK Integration to integrate the SDK into your application.

2. Configure a license for the SDK

Click Get License to obtain a trial license. You will get two strings: the license URL licenceURL and the decryption key licenceKey.
Before you use the features of MLVB Enterprise Edition in your application, complete the following configurations (preferably in the application class).

public class MApplication extends Application {
    @Override
   public void onCreate() {
       super.onCreate();
       String licenceURL = ""; // The license URL obtained
       String licenceKey = ""; // The license key obtained
       TXLiveBase.getInstance().setLicence(this, licenceURL, licenceKey);
   }
}

3. Initialize the V2TXLivePusher component

Create a V2TXLivePusher object, which will be responsible for publishing operations.

V2TXLivePusher mLivePusher = new V2TXLivePusherImpl(this, V2TXLiveDef.V2TXLiveMode.TXLiveMode_RTMP); // Set the live streaming protocol to RTMP

4. Enable camera preview

Before enabling camera preview, you must first provide the SDK with a TXCloudVideoView object to display video images. Given that TXCloudVideoView is inherited from FrameLayout in Android, you can:

1. Add a video rendering control in the XML file:

   <com.tencent.rtmp.ui.TXCloudVideoView   
         android:id="@+id/pusher_tx_cloud_view"  
         android:layout_width="match_parent" 
         android:layout_height="match_parent" /> 
   

2. Call startCamera in V2TXLivePusher to enable camera preview for your mobile phone.

   // Enable preview for the local camera    
   TXCloudVideoView mPusherView = (TXCloudVideoView) findViewById(R.id.pusher_tx_cloud_view); 
   mLivePusher.setRenderView(mPusherView);
   mLivePusher.startCamera(true);
   

5. Start and stop publishing

After calling startCamera to enable camera preview, you can call the startPush API in V2TXLivePusher to start publishing. You can use TRTC’s URL or an RTMP URL for publishing. The former uses UDP. It offers better streaming quality and supports co-anchoring.

// Start publishing. You can use the `trtc://` or `rtmp://` protocol. The former supports co-anchoring.
String rtmpURL = "trtc://cloud.tencent.com/push/streamid?sdkappid=1400188888&userId=A&usersig=xxxxx";  //This URL supports co-anchoring.
String rtmpURL = "rtmp://test.com/live/streamid?txSecret=xxxxx&txTime=xxxxxxxx";    //This URL does not support co-anchoring. The stream is published to a live streaming CDN.
int ret = mLivePusher.startPush(rtmpURL.trim());  
if (ret == V2TXLIVE_ERROR_INVALID_LICENSE) {    
   Log.i(TAG, "startRTMPPush: license verification failed");  
}       

Call stopPush in V2TXLivePusher to stop publishing streams.

//Stop publishing
mLivePusher.stopPush();

Note：

If you have enabled camera preview, please disable it when you stop publishing streams.

• How can I obtain a valid publishing URL?
  Activate CSS and, in the CSS console, go to CSS Toolkit > Address Generator to generate a publishing URL. For more information, see Publishing/Playback URL.
• Why is V2TXLIVE_ERROR_INVALID_LICENSE returned?
  If the startPush API returns V2TXLIVE_ERROR_INVALID_LICENSE, it means your license verification failed. Please check your configuration against Step 2. Configure a license for the SDK.

6. Publish audio-only streams

If your live streaming scenarios involve audio only, you can skip Step 4 or call stopCamera before startPush.

V2TXLivePusher mLivePusher = new V2TXLivePusherImpl(this, V2TXLiveDef.V2TXLiveMode.TXLiveMode_RTMP); // Set the live streaming protocol to RTMP
mLivePusher.startMicrophone();
// Start publishing. You can use the `trtc://` or `rtmp://` protocol. The former supports co-anchoring.
String rtmpURL = "trtc://cloud.tencent.com/push/streamid?sdkappid=1400188888&userId=A&usersig=xxxxx";  //This URL supports co-anchoring.
String rtmpURL = "rtmp://test.com/live/streamid?txSecret=xxxxx&txTime=xxxxxxxx";    //This URL does not support co-anchoring. The stream is published to a live streaming CDN.
int ret = mLivePusher.startPush(rtmpURL.trim());  

Note：

If you publish audio-only streams but no streams can be pulled from an RTMP, FLV, or HLS playback URL, there is a problem with your line configuration, please submit a ticket for help.

7. Set video quality

Call setVideoQuality in V2TXLivePusher to set the quality of videos watched by audience. The encoding parameters set determine the quality of videos presented to audience. The local video watched by the host is the original HD version that has not been encoded or compressed, and is therefore not affected by the settings. For details, please see Setting Video Quality.

8. Set the beauty filter style and skin brightening and rosy skin effects

Call getBeautyManager in V2TXLivePusher to get a TXBeautyManager instance to set beauty filters.

Beauty filter style

The SDK has three built-in beauty filter algorithms, each corresponding to a beauty filter style. Choose one that best fits your product positioning. For the definitions, see TXLiveConstants.java.

You can call the setBeautyStyle API of TXBeautyManager to set the beauty filter style.

9. Set color filters

• Call getBeautyManager in V2TXLivePusher to get a TXBeautyManager instance to set color filters.
• Call the setFilter API in TXBeautyManager to set color filters. Color filters are a technology that adjusts the color tone of sections of an image. For example, it may lighten the yellow sections of an image to achieve the effect of skin brightening, or add warm tones to a video to give it a refreshing and soft boost.
• Call the setFilterStrength API in TXBeautyManager to set the strength of a color filter. The higher the strength, the more obvious the effect.

Based on our experience of operating Mobile QQ and Now Live, it’s not enough to use only the setBeautyStyle API in TXBeautyManager to set the beauty filter style. The setBeautyStyle API must be used together with setFilter to produce richer effects. Given this, our designers have developed 17 built-in color filters for you to choose from.

// Select a color filter file to use   
Bitmap filterBmp = decodeResource(getResources(), R.drawable.filter_biaozhun);  
mLivePusher.getBeautyManager().setFilter(filterBmp);   
mLivePusher.getBeautyManager().setFilterStrength(0.5f);  

10. Manage devices

V2TXLivePusher provides a series of APIs for the control of devices. You can call getDeviceManager to get a TXDeviceManager instance for device management. For detailed instructions, please see TXDeviceManager API.

11. Set the video mirroring effect for audience

Call setRenderMirror in V2TXLivePusher to set the camera mirror mode, which affects the way video images are presented to audience. By default, the local video watched by the host is flipped when the front camera is used, which creates the same effect as a mirror does. The video watched by audience is the same as that watched by the host, as shown below.

12. Publish streams in landscape mode

In most cases, hosts stream while holding their phones vertically, and audience watch videos in portrait resolutions (e.g., 540 × 960). However, there are also cases where hosts hold phones horizontally, and ideally, audience should watch videos in landscape resolutions (960 × 540).

By default, V2TXLivePusher outputs videos in portrait resolutions. You can publish landscape-mode videos to audience by modifying a parameter of the setVideoQuality API.

mLivePusher.setVideoQuality(mVideoResolution, isLandscape ? V2TXLiveVideoResolutionModeLandscape : V2TXLiveVideoResolutionModePortrait);   

13. Set audio effects

Call getAudioEffectManager in V2TXLivePusher to get a TXAudioEffectManager instance, which can be used to mix background music and set in-ear monitoring, reverb, and other audio effects. Background music mixing means mixing into the published stream the music played by the host’s phone so that audience can also hear the music.

• Call the enableVoiceEarMonitor API in TXAudioEffectManager to enable in-ear monitoring, which allows hosts to hear their vocals in earphones when they sing.
• Call the setVoiceReverbType API in TXAudioEffectManager to add reverb effects such as karaoke, hall, husky, and metal. The effects are applied to the videos watched by audience.
• Call the setVoiceChangerType API in TXAudioEffectManager to add voice changing effects such as little girl and middle-aged man to enrich host-audience interaction. The effects are applied to the videos watched by audience.

Note：

For detailed instructions, please see TXAudioEffectManager API.

14. Set watermarks

Call setWatermark in V2TXLivePusher to add a watermark to videos output by the SDK. The position of the watermark is determined by the (x, y, scale) parameter passed in.

• The watermark image must be in PNG rather than JPG format. The former carries opacity information, which allows the SDK to better address the image aliasing issue (changing the extension of a JPG image to PNG won’t work).
• The (x, y, scale) parameter specifies the normalized coordinates of the watermark relative to the resolution of the published video. For example, if the resolution of the published video is 540 x 960, and (x, y, scale) is set to （0.1, 0.1, 0.1）, the actual pixel coordinates of the watermark will be (540 x 0.1, 960 x 0.1). The width of the watermark image will be the video width x 0.1, and the height will be scaled automatically.

// Set a video watermark
mLivePusher.setWatermark(BitmapFactory.decodeResource(getResources(),R.drawable.watermark), 0.03f, 0.015f, 1f);

15. Inform hosts of poor network conditions

Hosts should be informed when their network conditions are bad and be prompted to check their network.
You can capture the V2TXLIVE_WARNING_NETWORK_BUSY event using onWarning in V2TXLivePusherObserver. The event indicates poor network conditions for hosts, which result in stuttering for audience. When this event occurs, you can send a UI message about poor network conditions to hosts.

@Override
public void onWarning(int code, String msg, Bundle extraInfo) {
    if (code == V2TXLiveCode.V2TXLIVE_WARNING_NETWORK_BUSY) {
        showNetBusyTips(); // Show a “network busy” message
    }
}

16. Send SEI messages

Call the sendSeiMessage API in V2TXLivePusher to send SEI messages. SEI refers to the supplementary enhancement information of encoded video. It is not used most of the time, but you can insert custom information into SEI messages. The information will be forwarded to audience by live streaming CDNs. The applications for SEI messages include:

• Live quiz: The publisher can use SEI messages to send questions to the audience. SEI can ensure synchronization among audio, video, and the questions.
• Live showroom: The publisher can use SEI messages to display lyrics to the audience in real time. The effects are not affected by reduction in video encoding quality.
• Online education: The publisher can use SEI messages to display pointers and sketches on slides to the audience in real time.

Custom data is inserted directly into video data and therefore cannot be too large in size (preferably several bytes). It’s common to insert information such as custom timestamps.

//Sample code for Android
int payloadType = 5;
String msg = "test";
mTXLivePusher.sendSeiMessage(payloadType, msg.getBytes("UTF-8"));

Common open-source players or web players are incapable of parsing SEI messages. You must use V2TXLivePlayer, the built-in player of LiteAVSDK.

1. Configuration:

   int payloadType = 5;
   mTXLivePlayer.enableReceiveSeiMessage(true, payloadType)
   

2. If the video streams played by V2TXLivePlayer contain SEI messages, you will receive the messages via the onReceiveSeiMessage callback in V2TXLivePlayerObserver.

Event Handling

Listening for events

The SDK listens for publishing events and errors via the V2TXLivePusherObserver delegate. See V2TXLiveCode for a detailed list of events and error codes.

Errors

An error indicates that the SDK encountered a serious problem that made it impossible for stream publishing to continue.

Warnings

A warning indicates that the SDK encountered a problem whose severity level is warning. Warning events trigger tentative protection or recovery logic and can often be resolved.