tencent cloud

Basics

This document introduces the live playback feature of the Video Cloud SDK.

Live streaming and video on demand

• In live streaming, the video streams published by hosts in real time are the source of streaming. When hosts stop publishing streams, the video played stops. Since video is streamed in real time, players do not have progress bars when they play live streaming URLs.
• In video on demand (VOD), video files in the cloud are the source of streaming. Videos can be played at any time as long as they are not deleted from the cloud, and the playback progress can be adjusted using the progress bar. Video streaming websites such as Tencent Video and Youku Tudou are typical applications of VOD.

Supported protocols

The table below lists the common protocols used for live streaming. We recommend FLV URLs (which start with http and end with flv) for LVB and WebRTC for LEB. For more information, please see LEB.

Note：

LVB and LEB are priced differently. For details, please see LVB Billing Overview and LEB Billing Overview.

Notes

The Video Cloud SDK does not impose any limit on the sources of playback URLs, which means you can use it to play both Tencent Cloud and non-Tencent Cloud URLs. However, the player of the SDK supports only live streaming URLs in FLV, RTMP, HLS (M3U8), and WebRTC formats and VOD URLs in MP4, HLS (M3U8), and FLV formats.

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.

Integration

Step 1. Download the SDK

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

Step 2. Configure License Authorization for SDK

1. Obtain license authorization：
   • If you have obtained the relevant license authorization，need to Get License URL and License Key in Cloud Live Console
     
   • If you have not yet obtained the license authorization，Please reference Adding and Renewing Licenses to make an application.
2. Before your App calls SDK-related functions (it is recommended in the Application class), set the following settings:

   public class MyApplication extends Application {
   @Override
   public void onCreate() {
   super.onCreate();
   String licenceURL = ""; // your licence url
   String licenceKey = ""; // your licence key
   V2TXLivePremier.setEnvironment("GDPR");  // set your environment
   V2TXLivePremier.setLicence(this, licenceURL, licenceKey);
   V2TXLivePremier.setObserver(new V2TXLivePremierObserver() {
           @Override
           public void onLicenceLoaded(int result, String reason) {
               Log.i(TAG, "onLicenceLoaded: result:" + result + ", reason:" + reason);
           }
       });
   }
   

Note：

The packageName configured in the license must be the same as the application itself, otherwise the play stream will fail.

Step 3. Create a rendering view

For the player to display video images, you need to add a rendering view in the layout XML file:

<com.tencent.rtmp.ui.TXCloudVideoView
           android:id="@+id/video_view"
           android:layout_width="match_parent"
           android:layout_height="match_parent"
           android:layout_centerInParent="true"
           android:visibility="visible"/>

Step 4. Create a player object

The V2TXLivePlayer module in the Video Cloud SDK offers live playback capabilities. Use the setRenderView API to associate the module with the video_view control added to the UI in Step 3.

// mPlayerView is the view added in step 1
TXCloudVideoView mView = (TXCloudVideoView) view.findViewById(R.id.video_view);
// Create a player object
V2TXLivePlayer mLivePlayer = new V2TXLivePlayerImpl(mContext);
// Associate the player object with the view
mLivePlayer.setRenderView(mView);

Step 5. Start playback

String flvUrl = "http://2157.liveplay.myqcloud.com/live/2157_xxxx.flv";
mLivePlayer.startPlay(flvUrl); 

Step 6. Change the fill mode

• view: size and position
  You can modify the size and position of video images by adjusting the size and position of the video_view control added in Step3.
• setRenderFillMode: aspect fill or aspect fit

  Value	Description
  V2TXLiveFillModeFill	Images are scaled to fill the entire screen, and the excess parts are cropped. There are no black bars in this mode, but images may not be displayed in whole.
  V2TXLiveFillModeFit	Images are scaled as large as the longer side can go. Neither side exceeds the screen after scaling. Images are centered, and there may be black bars.

• setRenderRotation: clockwise rotation of video

  Value	Description
  V2TXLiveRotation0	Original
  V2TXLiveRotation90	Rotate 90 degrees clockwise
  V2TXLiveRotation180	Rotate 180 degrees clockwise
  V2TXLiveRotation270	Rotate 270 degrees clockwise

// Set the fill mode
mLivePlayer.setRenderFillMode(V2TXLiveFillModeFit);
// Set the rotation of video
mLivePlayer.setRenderRotation(V2TXLiveRotation0);

Step 7. Pause playback

Technically speaking, you cannot pause a live playback. In this document, by pausing playback, we mean freezing video and disabling audio. In the meantime, new video streams continue to be sent to the cloud. When you resume playback, it starts from the time of resumption. This is in contrast to VOD. With VOD, when you pause and resume playback, the player behaves the same way as it does when you pause and resume a local video file.

// Pause playback
mLivePlayer.pauseAudio();
mLivePlayer.pauseVideo();
// Resume playback
mLivePlayer.resumeAudio();
mLivePlayer.resumeVideo();

Step 8. Stop playback

Call stopPlay to stop playback.

mLivePlayer.stopPlay();  

Step 9. Take a screenshot

Call snapshot to take a screenshot of the live video streamed. This method captures a frame of the streamed video. To capture the UI, use the corresponding API of the Android system.

mLivePlayer.setObserver(new MyPlayerObserver());
mLivePlayer.snapshot();
// Get the screenshot taken in the onSnapshotComplete callback of MyPlayerObserver
private class MyPlayerObserver extends V2TXLivePlayerObserver  {
  ...
  @Override
  public void onSnapshotComplete(V2TXLivePlayer v2TXLivePlayer, Bitmap bitmap) {
  }
  ...
}

Latency Control

The live playback feature of the SDK is not based on FFmpeg, but Tencent Cloud’s proprietary playback engine, which is why the SDK offers better latency control than open-source players do. We provide three latency control modes, which can be used for showrooms, game streaming, and hybrid scenarios.

• Comparison of the three modes

  Mode	Stutter	Average Latency	Scenario	Remarks
  Speedy	More likely than the speedy mode	2-3s	Live showroom (Chongding Dahui)	The mode delivers low latency and is suitable for latency-sensitive scenarios.
  Smooth	Least likely of the three	>= 5s	Game streaming (Penguin Esports)	Playback is least likely to stutter in this mode, which makes it suitable for ultra-high-bitrate streaming of games such as PUBG.
  Auto	Self-adaptive to network conditions	2-8s	Hybrid	The better network conditions at the audience end, the lower the latency.

• Code to integrate the three modes

  // Auto mode
  mLivePlayer.setCacheParams(1.0f, 5.0f);
  // Speedy mode
  mLivePlayer.setCacheParams(1.0f, 1.0f);
  // Smooth mode
  mLivePlayer.setCacheParams(5.0f, 5.0f);
  // Start playback after configuration
  

Note：

For more information on stuttering and latency control, see Video Stutter.

Listening for SDK Events

You can bind a V2TXLivePlayerObserver to your V2TXLivePlayer object to receive callback notifications about the player status, playback volume, first audio/video frame, statistics, warning and error messages, etc.

Periodically triggered notification

• The onStatisticsUpdate callback notification is triggered every 2 seconds to update you on the player’s status in real time. Like a car’s dashboard, the callback gives you information about the SDK, such as network conditions and video information.

  Parameter	Description
  appCpu	CPU usage (%) of the application
  systemCpu	CPU usage (%) of the system
  width	Video width
  height	Video height
  fps	Frame rate (fps)
  audioBitrate	Audio bitrate (Kbps)
  videoBitrate	Video bitrate (Kbps)

• The onPlayoutVolumeUpdate callback, which notifies you of the player’s volume, works only after you call enableVolumeEvaluation to enable the volume reminder. You can set the interval of the callback by specifying the intervalMs parameter of enableVolumeEvaluation.

Event-triggered notifications

Other callbacks are triggered when specific events occur.