Unity 用UniversalMediaPlayer 2.0.3版本视频流插件 只用视频流地址 不播放当前视频 获取第一帧显示在UI上

以下是使用UniversalMediaPlayer 2.0.3版本视频流插件获取第一帧并在UI上显示的示例代码：

using UnityEngine;
using UnityEngine.UI;
using System.Collections;
using System;

public class VideoStreamController : MonoBehaviour
{
    public RawImage image; //UI上的RawImage组件
    public string videoStreamUrl; //视频流地址

    private UniversalMediaPlayer mediaPlayer; //视频流播放器
    private bool isReadyToGetFirstFrame = false; //是否准备获取第一帧

    void Start()
    {
        //初始化视频流播放器
        mediaPlayer = new UniversalMediaPlayer();
        mediaPlayer.EventManager.OnPlayerReady += OnPlayerReady;
        mediaPlayer.EventManager.OnPlayerOpening += OnPlayerOpening;
        mediaPlayer.EventManager.OnPlayerBuffering += OnPlayerBuffering;
        mediaPlayer.EventManager.OnPlayerPlaying += OnPlayerPlaying;
        mediaPlayer.EventManager.OnPlayerPaused += OnPlayerPaused;
        mediaPlayer.EventManager.OnPlayerStopped += OnPlayerStopped;
        mediaPlayer.EventManager.OnPlayerEndReached += OnPlayerEndReached;
        mediaPlayer.EventManager.OnPlayerEncounteredError += OnPlayerEncounteredError;
        mediaPlayer.InitPlayer();
    }

    void Update()
    {
        //如果准备获取第一帧并且视频流播放器已经准备好，就获取第一帧并显示在UI上
        if (isReadyToGetFirstFrame && mediaPlayer != null && mediaPlayer.IsReady)
        {
            Texture2D frameTexture = mediaPlayer.GetTexture(0);
            if (frameTexture != null)
            {
                image.texture = frameTexture;
                isReadyToGetFirstFrame = false;
            }
        }
    }

    void OnDestroy()
    {
        //销毁视频流播放器
        if (mediaPlayer != null)
        {
            mediaPlayer.Stop();
            mediaPlayer = null;
        }
    }

    void OnPlayerReady(UniversalMediaPlayer mediaPlayer, IntPtr userdata)
    {
        //视频流播放器准备好后开始播放
        mediaPlayer.Play(videoStreamUrl);
    }

    void OnPlayerOpening(UniversalMediaPlayer mediaPlayer, IntPtr userdata)
    {
        //视频流开始打开时设置准备获取第一帧标志位
        isReadyToGetFirstFrame = true;
    }

    void OnPlayerBuffering(UniversalMediaPlayer mediaPlayer, float bufferPercent, IntPtr userdata)
    {
        //视频流缓冲进度变化时不做任何处理
    }

    void OnPlayerPlaying(UniversalMediaPlayer mediaPlayer, IntPtr userdata)
    {
        //视频流播放时不做任何处理
    }

    void OnPlayerPaused(UniversalMediaPlayer mediaPlayer, IntPtr userdata)
    {
        //视频流暂停时不做任何处理
    }

    void OnPlayerStopped(UniversalMediaPlayer mediaPlayer, IntPtr userdata)
    {
        //视频流停止时不做任何处理
    }

    void OnPlayerEndReached(UniversalMediaPlayer mediaPlayer, IntPtr userdata)
    {
        //视频流播放结束时不做任何处理
    }

    void OnPlayerEncounteredError(UniversalMediaPlayer mediaPlayer, IntPtr userdata)
    {
        //视频流播放出错时不做任何处理
    }
}

在上述代码中，我们使用UniversalMediaPlayer的GetTexture方法来获取第一帧，并将其显示在UI上的RawImage组件中。注意，在OnPlayerOpening回调中设置isReadyToGetFirstFrame标志位为true，是为了在视频流开始打开时获取第一帧，避免等待太长时间。