Vuforia AR应用问题：如何实现识别图像时仅播放对应视频

Hey there! Let’s tackle this video playback issue you’re facing. The root problem here is that all your videos are firing up and running in the background as soon as the app launches—even when their matching Image Target isn’t in view. Here’s how to adjust your logic so each video only starts playing exactly when its target is recognized:

Step 1: Initialize Videos in a Paused State #

First, make sure none of your videos auto-play when the app starts. Most AR frameworks (like Vuforia or ARCore) let you control video playback via components or scripts. For example, if you’re using Unity:

• Set the PlayOnAwake property of every VideoPlayer component to false.
• Add a quick start script to reset each video to the beginning and pause it:

  public VideoPlayer myTargetVideo;
  
  void Start()
  {
      myTargetVideo.Pause();
      myTargetVideo.time = 0; // Reset video to start
  }
  

Step 2: Trigger Playback on Target Detection #

Next, hook into your AR framework’s target detection events. All major tools provide callbacks for when an Image Target is found. When this happens:

1. Pause and reset all other videos (to stop any background playback)
2. Reset your target’s video to the start
3. Start playing the video

Here’s a sample callback implementation (Unity + Vuforia example):

// Keep a reference to all your video players in a list
public List<VideoPlayer> allVideoPlayers;
public VideoPlayer targetVideo;

public void OnImageTargetFound()
{
    // Stop and reset all other videos
    foreach (var video in allVideoPlayers)
    {
        if (video != targetVideo)
        {
            video.Pause();
            video.time = 0;
        }
    }

    // Start this target's video from the beginning
    targetVideo.time = 0;
    targetVideo.Play();
}

Step 3: Pause/Reset When Target is Lost #

Don’t forget to handle the case when the target moves out of view. Add a callback for when the target is lost to pause the video (and optionally reset it to the start for next time):

public void OnImageTargetLost()
{
    targetVideo.Pause();
    targetVideo.time = 0; // Optional: Reset so it's ready for next detection
}

Step 4: Optimize Video Loading (Optional) #

If your videos are large, consider loading them dynamically only when their target is first detected instead of preloading all at launch. This saves memory and eliminates any chance of background playback before detection. For example, in Unity:

public void OnImageTargetFound()
{
    // Load the video clip asynchronously
    StartCoroutine(LoadAndPlayVideo());
}

IEnumerator LoadAndPlayVideo()
{
    var videoClipRequest = Resources.LoadAsync<VideoClip>("MyTargetVideo");
    yield return videoClipRequest;

    targetVideo.clip = videoClipRequest.asset as VideoClip;
    targetVideo.Play();
}

By following these steps, each video will only play when its Image Target is actively detected, reset to the start every time the target is found, and stop immediately when the target is out of sight. No more half-played videos ruining the user experience!

内容的提问来源于stack exchange，提问作者Ibrewster