首页 \ 问答 \ 使用Google Cast - 媒体播放器库创建自定义接收器(Creating a custom receiver with the Google Cast - Media Player Library)

使用Google Cast - 媒体播放器库创建自定义接收器(Creating a custom receiver with the Google Cast - Media Player Library)

java

 我想为我的自定义接收器实现媒体播放器功能。 在谷歌开发者网站上，我找到了实现发件人和样式媒体接收器应用程序的描述。  
 我做了这个样本，它工作正常。 我可以将Google云端硬盘上托管的MP3文件投射到我的chromecast设备上。  
 现在，我已经实现了一个自定义接收器（参见附件），该接收器应该能够播放指向m3u8文件的URL。 为此，我正在使用Google建议的媒体播放器库。  
<body>
<div>
<p id='text'> </p>
<video id='vid'> </video>
</div>
<script type="text/javascript" src="https://www.gstatic.com/cast/sdk/libs/receiver/2.0.0/cast_receiver.js"></script>
<script type="text/javascript" src="https://www.gstatic.com/cast/sdk/libs/mediaplayer/1.0.0/media_player.js"></script>



<script type="text/javascript">
// If you set ?Debug=true in the URL, such as a different App ID in the
// developer console, include debugging information.
if (window.location.href.indexOf('Debug=true') != -1) {
    cast.receiver.logger.setLevelValue(cast.receiver.LoggerLevel.DEBUG);
    cast.player.api.setLoggerLevel(cast.player.api.LoggerLevel.DEBUG);
}

console.log("mediaElement set");
var mediaElement = document.getElementById('vid');

// Create the media manager. This will handle all media messages by default.
window.mediaManager = new cast.receiver.MediaManager(mediaElement);

// Remember the default value for the Receiver onLoad, so this sample can Play
// non-adaptive media as well.
window.defaultOnLoad = mediaManager.onLoad;

mediaManager.onLoad = function (event) {
    // The Media Player Library requires that you call player unload between
    // different invocations.
    if (window.player !== null) {
        player.unload();    // Must unload before starting again.
        window.player = null;
    }
    // This trivial parser is by no means best practice, it shows how to access
    // event data, and uses the a string search of the suffix, rather than looking
    // at the MIME type which would be better.  In practice, you will know what
    // content you are serving while writing your player.


    if (event.data['media'] && event.data['media']['contentId']) {
    console.log('Starting media application');


    var t = document.getElementById('text');
    t.innerHTML = event.data['media'];
    console.log("EventData: "+event.data);
    console.log("EventData-Media: "+event.data['media']);
    console.log("EventData-ContendID: "+event.data['media']['contentId']);

    var url = event.data['media']['contentId'];
    console.log("URL: "+url);

    // Create the Host - much of your interaction with the library uses the Host and
    // methods you provide to it.
    window.host = new cast.player.api.Host(
        {'mediaElement':mediaElement, 'url':url});
    var ext = url.substring(url.lastIndexOf('.'), url.length);
    var initStart = event.data['media']['currentTime'] || 0;
    var autoplay = event.data['autoplay'] || true;
    var protocol = null;
    mediaElement.autoplay = autoplay;  // Make sure autoplay get's set

    protocol = cast.player.api.CreateHlsStreamingProtocol(host);

    host.onError = function(errorCode) {
      console.log("Fatal Error - "+errorCode);
      if (window.player) {
        window.player.unload();
        window.player = null;
      }
    };
    // If you need cookies, then set withCredentials = true also set any header
    // information you need.  If you don't need them, there can be some unexpected
    // effects by setting this value.
    //      host.updateSegmentRequestInfo = function(requestInfo) {
    //        requestInfo.withCredentials = true;
    //      };
    console.log("we have protocol "+ext);
    if (protocol !== null) {
      console.log("Starting Media Player Library");
      window.player = new cast.player.api.Player(host);
      window.player.load(protocol, initStart);
    }
    else {
      window.defaultOnLoad(event);    // do the default process
    }
  }   
}

window.player = null;
console.log('Application is ready, starting system');
window.castReceiverManager = cast.receiver.CastReceiverManager.getInstance();
castReceiverManager.start();
</script>
</body>
 
 我已经想通了，可以使用Media Player Library转换.m3u8，.ism和.mpd文件。 所以我创建了一个如下的m3u8文件，将其托管到Google云端硬盘，并尝试将其投射到我的自定义接收器。  
#EXTM3U
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=173952
https://www.googledrive.com/host/0B1x31lLRAxTMRndtNkhSWVdGLVE
 
 但它不起作用。 我使用Goolge Cast Developer Console来调试自定义接收器。 通过排除  
window.player.load(protocol, initStart);
 
 命令，我在控制台上收到致命错误。  
 我认为问题在于自定义接收器代码，因为谷歌文档中的发件人应用程序与样式化的媒体接收器一起工作正常。  
 是否有人知道此问题或在自定义接收器代码上看到一些问题？ 有谁知道如何调试风格的媒体播放器？ 如果我能看到哪些消息与样式化的媒体播放器交换会更容易，但如果我激活调试我看不到交换的消息。 

I would like to implement media player functionality to my custom receiver. On the google developer website, I found a description to implement a sender and a styled media receiver application. 
I have done this sample, and it works fine. I can cast a MP3 file hosted on Google Drive to my chromecast device. 
Now, I have implemented a custom receiver (see attachment) which should be able to play an URL refered to a m3u8 file. For this, I am using the Media Player Library as suggested from Google. 
<body>
<div>
<p id='text'> </p>
<video id='vid'> </video>
</div>
<script type="text/javascript" src="https://www.gstatic.com/cast/sdk/libs/receiver/2.0.0/cast_receiver.js"></script>
<script type="text/javascript" src="https://www.gstatic.com/cast/sdk/libs/mediaplayer/1.0.0/media_player.js"></script>



<script type="text/javascript">
// If you set ?Debug=true in the URL, such as a different App ID in the
// developer console, include debugging information.
if (window.location.href.indexOf('Debug=true') != -1) {
    cast.receiver.logger.setLevelValue(cast.receiver.LoggerLevel.DEBUG);
    cast.player.api.setLoggerLevel(cast.player.api.LoggerLevel.DEBUG);
}

console.log("mediaElement set");
var mediaElement = document.getElementById('vid');

// Create the media manager. This will handle all media messages by default.
window.mediaManager = new cast.receiver.MediaManager(mediaElement);

// Remember the default value for the Receiver onLoad, so this sample can Play
// non-adaptive media as well.
window.defaultOnLoad = mediaManager.onLoad;

mediaManager.onLoad = function (event) {
    // The Media Player Library requires that you call player unload between
    // different invocations.
    if (window.player !== null) {
        player.unload();    // Must unload before starting again.
        window.player = null;
    }
    // This trivial parser is by no means best practice, it shows how to access
    // event data, and uses the a string search of the suffix, rather than looking
    // at the MIME type which would be better.  In practice, you will know what
    // content you are serving while writing your player.


    if (event.data['media'] && event.data['media']['contentId']) {
    console.log('Starting media application');


    var t = document.getElementById('text');
    t.innerHTML = event.data['media'];
    console.log("EventData: "+event.data);
    console.log("EventData-Media: "+event.data['media']);
    console.log("EventData-ContendID: "+event.data['media']['contentId']);

    var url = event.data['media']['contentId'];
    console.log("URL: "+url);

    // Create the Host - much of your interaction with the library uses the Host and
    // methods you provide to it.
    window.host = new cast.player.api.Host(
        {'mediaElement':mediaElement, 'url':url});
    var ext = url.substring(url.lastIndexOf('.'), url.length);
    var initStart = event.data['media']['currentTime'] || 0;
    var autoplay = event.data['autoplay'] || true;
    var protocol = null;
    mediaElement.autoplay = autoplay;  // Make sure autoplay get's set

    protocol = cast.player.api.CreateHlsStreamingProtocol(host);

    host.onError = function(errorCode) {
      console.log("Fatal Error - "+errorCode);
      if (window.player) {
        window.player.unload();
        window.player = null;
      }
    };
    // If you need cookies, then set withCredentials = true also set any header
    // information you need.  If you don't need them, there can be some unexpected
    // effects by setting this value.
    //      host.updateSegmentRequestInfo = function(requestInfo) {
    //        requestInfo.withCredentials = true;
    //      };
    console.log("we have protocol "+ext);
    if (protocol !== null) {
      console.log("Starting Media Player Library");
      window.player = new cast.player.api.Player(host);
      window.player.load(protocol, initStart);
    }
    else {
      window.defaultOnLoad(event);    // do the default process
    }
  }   
}

window.player = null;
console.log('Application is ready, starting system');
window.castReceiverManager = cast.receiver.CastReceiverManager.getInstance();
castReceiverManager.start();
</script>
</body>
 
I've figured out, that it's just possible to cast .m3u8, .ism and .mpd files with the Media Player Library. So I created a m3u8 file as follows, host it to Google Drive, and tried to cast it to my custom receiver. 
#EXTM3U
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=173952
https://www.googledrive.com/host/0B1x31lLRAxTMRndtNkhSWVdGLVE
 
But it doesn't works. I used the Goolge Cast Developer Console to debug the custom receiver. By exceuting the  
window.player.load(protocol, initStart);
 
command, I get an FATAL ERROR on the console. 
I think the problem is on the custom receiver code because the sender application from the google documentation works fine with the styled media receiver. 
Is there anyone who know this problem or see some issue on the custom receiver code? Has anyone a idea how I could debug the styled media player? It would be much easier if I could see which messages are exchanged with the styled media player but if I activate the debugging I can´t see the exchanged messages.

原文：https://stackoverflow.com/questions/26911309

更新时间：2022-10-16 12:10

最满意答案

 我认为问题出在Pair方法中。 当你这样做：  
 this.rates.get(new Pair(from, to));  
 您正在创建Pair的新实例，这与您在addRate方法中放入地图的addRate 。  
 如果您希望代码正常工作，您必须使用Pair类的相同实例或在Pair类上正确实现equals和hashCode方法。  
 以下是对HashMap内部工作的深入了解以及为使其工作所需做的工作： https ： //stackoverflow.com/a/6493946/2266098 

I think the problem is in the Pair method. When you do this:  
this.rates.get(new Pair(from, to)); 
you are creating a new instance of Pair, which is not the same as the one you've put into the map in the addRate method.  
If you want the code to work correctly, you either have to use the same instance of Pair class or correctly implement equals and hashCode method on Pair class. 
Here's a bit deeper insight into the inner working on HashMap and what you have to do to make it work: https://stackoverflow.com/a/6493946/2266098

使用Google Cast - 媒体播放器库创建自定义接收器(Creating a custom receiver with the Google Cast - Media Player Library)

最满意答案

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