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How To Make A Movie-watching App In A Few Hours

How To Make A Movie-watching App In A Few Hours

Since my girlfriend and I reside in different cities, we don’t get to spend much time in each other’s physical company. When we were on video chat one day, she said: “Hey, it’s been a while since the two of us went to the cinema together. When can we watch do that again… “

She had a point. It’s been quite some time…

Though we couldn’t see each other right away, we could watch a movie together online. I am aware that there are several apps available to achieve that. More and more of these apps and services have come out to help people stay in touch, especially since the pandemic started. Then it occured to me that, wouldn’t it be cool if I made an exclusive app just for the two of us?

So I went on staring my little project….

A few hours later, I got something looks like this:


As a developer, I enjoy constructing things and discussing how they are made. To help you better understand the implementation, I’m going to detail some of the most significant processes in the following parts.

The implementation

Set up the development environment

  • Android Studio (version 2.1 or later)
  • Android SDK 25, Android SDK Build-Tools 25.0.2, Android SDK Platform-Tools 25.x.x or later
  • An Android device (Android 4.1 or later) with a microphone and camera
  • Android is connected to the internet.


Here are a few things that need to be done first before you can start building with ZEGOCLOUD.

Now, we can start coding!

Feature overview

This is gonna be a simple app with the following features:

  • There will be two participants joining a room to watch a movie together. Let’s call them viewer A and viewer B.
  • To ensure that the two participants can have a truly synchronized watching together experience, I decided to play and stream the movie to the room from a separate device. Let’s call it the movie streamer. The consideration in this decision is that if the movie is played and streamed to the room from the device of one of the participants, then the streaming latency may result in a perceivable out-of-sync issue between the two participants. But if the movie is played and streamed from a separate device, then both participants will be subscribing to and playing the movie stream from the cloud, and the probability of having a perceivable out-of-sync issue will be much lower.
  • Participants in the room can have video chat and text chat while watching the movie together.
  • To make it simple, in this project, I set the maximum number of participants in a room to 3.

The movie streamer side – Play a movie and stream it the room

Step 1: Create a ZegoExpressEngine instance.

/// Define the ZegoExpressEngine object
ZegoExpressEngine engine;
/// Specify the AppID and AppSign for SDK authentication
/// AppID Format:123456789L
long appID = ; 
/// AppSign Format:"0123456789012345678901234567890123456789012345678901234567890123"
String appSign = "";
/// Create a ZegoExpressEngine instance
engine = ZegoExpressEngine.createEngine(appID, appSign, true, ZegoScenario.GENERAL, getApplication(), null); 

Step 2: Enable custom video capture for the engine.

ZegoCustomVideoCaptureConfig videoCaptureConfig = new ZegoCustomVideoCaptureConfig();
// Use RAW_DATA as video buffer data type
videoCaptureConfig.bufferType = ZegoVideoBufferType.RAW_DATA;  engine.enableCustomVideoCapture(true, videoCaptureConfig, ZegoPublishChannel.MAIN);

Step 3: Set a callback handler for custom video capture and implement the callback methods.

// Set the engine itself as the callback handler object
engine.setCustomVideoCaptureHandler(new IZegoCustomVideoCaptureHandler() {    
     public void onStart(ZegoPublishChannel channel) {         
     // On receiving the onStart callback, start to capture video and send the captured video frame data to the ZegoExpressEngine.

      public void onStop(ZegoPublishChannel channel) {         
      // On receiving the onStop callback, stop the video capture process.

Step 4: Join a room.

/// Create a user
ZegoUser user = new ZegoUser("userA"); 
/// Join a room
engine.loginRoom("room", user);

Step 5: Set up a video event handler for the ZegoMediaPlayer. By setting up this handler, you can receive the video frame data of the movie being played through the callback onVideoFrame.

    new IZegoMediaPlayerVideoHandler() {
        public void onVideoFrame(ZegoMediaPlayer zegoMediaPlayer, ByteBuffer[] byteBuffers, int[] ints, ZegoVideoFrameParam zegoVideoFrameParam) { 
        if (RoomManager.getInstance().isCanSenRawData()) {
            int totalDataLength = byteBuffers[0].capacity();
            if (tempByteBuffer == null || tempByteBuffer.capacity() != totalDataLength) {
                tempByteBuffer = ByteBuffer.allocateDirect(byteBuffers[0].capacity()).put(byteBuffers[0]);
            } else {
            ZegoSDKManager.getInstance().getStreamService().sendCustomVideoCaptureRawData(tempByteBuffer, tempByteBuffer.capacity(), zegoVideoFrameParam);
    }, ZegoVideoFrameFormat.RGBA32);

Step 6: Start stream publishing. Load the movie from the specified file path (local file path or an URL that points to an internet media resource), and start playing the movie.

/// Start publishing the stream

mZegoMediaPlayer.loadResource(path, new IZegoMediaPlayerLoadResourceCallback() {
    public void onLoadResourceCallback(int code) {
        if (code == 0) {
            if (callback != null) {

Step 7: When there are no other participants in the room or the participant who is publishing stream leaves the room, stop publishing the stream, and the callback for stopping custom video capture will be triggered.

ZegoSDKManager.getInstance().getDeviceService().setCustomVideoCaptureHandler(new IZegoVideoCaptureCallback() {
    public void onStart(ZegoPublishChannel channel) {
        canSenRawData = true;

    public void onStop(ZegoPublishChannel channel) {
        canSenRawData = false;

The movie viewer side – subscribe to the movie stream to watch together, video chat, and text chat

To realize the watch together feature, we will need to implement the following:

  • The viewers subscribe to the video stream of the movie being played so they can watch it together.
  • Both viewers can have control over the movie playback. For example, either one of them can pause and resume the playback.
  • Stream publishing/subscribing and camera/microphone operations for video chat while watching the movie.
  • Sending and receiving real-time text messaging in the room.
The high-level program logic for movie playing:
  • The movie streamer will create a room first, and the viewers need to join the same room (by specifying the same Room ID when calling the loginRoom method). If viewers attempt to join a room that doesn’t exist or without a movie streamer in there, they will be promoted with a message Room doesn't exist. If the specified room has already reached its full capacity, then the room login will fail, and the user will be notified accordingly.
  • When a viewer clicks the Start Movie button, call the setRoomExtraInfo() to send a notification to the movie streamer. Upon receiving such notification through the onRoomExtraInfoUpdate() callback, the movie streamer will execute the logic to start playing the movie and start streaming the movie to the room.
  • The movie stream will then be received by both viewers and played on their devices.
/// start playing stream
engine.startPlayingStream("stream1", new ZegoCanvas(play_view));
  • Both viewers can call the setRoomExtraInfo(String roomID,String key,String value,null) method to control the movie playback (Play or Pause).

The following table shows the key-value parameters you can pass to the setRoomExtraInfo method to send out different notifications:

roomInfo0: movie being loaded…
1: movie playing
2: movie on pause
3: room has been closed
The high-level program logic for video chat:
  • After joining the room, viewer A (or B) can start publishing video from the camera with a unique Stream ID and also start the local preview.
  • When the other viewer joins the room and starts publishing his/her video to the room, the ZEGO Express SDK will send out an event notification accordingly. Viewer A (or B) then can start playing the other viewer’s video using the Stream ID received from the callback notification.
  • Both viewers can control their camera (e.g., switch between front/rear camera, turn on/off the camera) and microphone (e.g., mute/unmute) as they wish.
/// Switch between the front/rear camera

/// Turn on/off the camera

/// Mute or unmute the microphone
The high-level program logic for text chat:
  • Both viewers can send and receive real-time text messages in the room.
  • Call sendBroadcastMessage method to send a Broadcast Message (no longer than 1024 bytes) to other participants in the room.
/// Send broadcast messages
engine.sendBroadcastMessage(roomID, msg, new IZegoIMSendBroadcastMessageCallback() {
   public void onIMSendBroadcastMessageResult(int errorCode, long messageID) {   
    /// Returned result of sending broadcast messages       
  • Implement the callback method onIMRecvBroadcastMessage defined in IZegoEventHandler to listen for and handle the Broadcast Messages sent by other participants. You can get the details of the message from this callback, including the message content, message ID, time message sent, and message sender.
    java /// reveice message public void onIMRecvBroadcastMessage(String roomID, ArrayList<ZegoBroadcastMessageInfo> messageList){ }

How the final app looks like

The movie streamer view

The movie streamer view

Viewer view

Viewer view
Viewer view

Download Demo & Source Code →

You may download the demo app and try it yourself:

Demo instructions:
  1. Start the movie streamer, choose a movie, then configure the Room ID.
  2. Start the viewer app and enter the same Room ID.


I hope that after reading this article, you’ll see that making an app for watching movies together is not that hard at all. Ready to create your own app?

ZEGOCLOUD With our fully customizable and easy-to-integrate Live SDK, you can quickly build reliable, scalable, and interactive live streaming into your mobile, web, and desktop apps.

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