使用Exoplayer从Icecast流中提取元数据 [英] Extracting metadata from Icecast stream using Exoplayer

问题描述

自从Mediaplayer切换到简单的实现Exoplayer之后，我注意到加载时间大大缩短了，但我想知道流音频时是否存在任何内置功能，例如元数据更改监听器?

Since switching from Mediaplayer to a simple implementation Exoplayer I have noticed much improved load times but I'm wondering if there is any built in functionality such as a metadata change listener when streaming audio?

我已使用以下简单示例实现了Exoplayer:

I have implemented Exoplayer using a simple example as below:

    Uri uri = Uri.parse(url);
    DefaultSampleSource sampleSource =
            new DefaultSampleSource(new FrameworkSampleExtractor(context, uri, null), 2);
    TrackRenderer audioRenderer = new MediaCodecAudioTrackRenderer(sampleSource);
    mExoPlayerInstance.prepare(audioRenderer);
    mExoPlayerInstance.setPlayWhenReady(true);

推荐答案

我有一个AsyncTask从IceCast Stream启动ExoPlayer:

I have an AsyncTask that starts ExoPlayer from an IceCast Stream:

OkHttpClient okHttpClient = new OkHttpClient();

UriDataSource uriDataSource = new OkHttpDataSource(okHttpClient, userAgent, null, null, CacheControl.FORCE_NETWORK);
((OkHttpDataSource) uriDataSource).setRequestProperty("Icy-MetaData", "1");
((OkHttpDataSource) uriDataSource).setPlayerCallback(mPlayerCallback);

DataSource dataSource = new DefaultUriDataSource(context, null, uriDataSource);

ExtractorSampleSource sampleSource = new ExtractorSampleSource(uri, dataSource, allocator,
                    BUFFER_SEGMENT_COUNT * BUFFER_SEGMENT_SIZE);


MediaCodecAudioTrackRenderer audioRenderer = new MediaCodecAudioTrackRenderer(sampleSource,
MediaCodecSelector.DEFAULT, null, true, null, null,
AudioCapabilities.getCapabilities(context), AudioManager.STREAM_MUSIC);
mPlayerCallback.playerStarted();
exoPlayer.prepare(audioRenderer);

OkHttpDataSource是使用OkHttpClient实现HttpDataSource的类.它创建InputStream作为来自请求的响应.我从AACDecoder库 https://github.com/vbartacek/aacdecoder-android/blob/master/decoder/src/com/spoledge/aacdecoder/IcyInputStream.java 并根据响应用IcyInputStream替换InputStream:

OkHttpDataSource is the class that implements HttpDataSource using OkHttpClient. It creates InputStream as a response from a request. I included this class from AACDecoder library https://github.com/vbartacek/aacdecoder-android/blob/master/decoder/src/com/spoledge/aacdecoder/IcyInputStream.java and replace InputStream with IcyInputStream depending on the response:

(在OkHttpDataSource的open()中)

(In open() of OkHttpDataSource)

try {
  response = okHttpClient.newCall(request).execute();
  responseByteStream = response.body().byteStream();

  String icyMetaIntString = response.header("icy-metaint");
  int icyMetaInt = -1;
  if (icyMetaIntString != null) {
    try {
      icyMetaInt = Integer.parseInt(icyMetaIntString);
      if (icyMetaInt > 0)
        responseByteStream = new IcyInputStream(responseByteStream, icyMetaInt, playerCallback);
    } catch (Exception e) {
      Log.e(TAG, "The icy-metaint '" + icyMetaInt + "' cannot be parsed: '" + e);
    }
  }

} catch (IOException e) {
  throw new HttpDataSourceException("Unable to connect to " + dataSpec.uri.toString(), e,
      dataSpec);
}

现在IcyInputStream可以捕获medatada并调用回调对象(此处为playerCallback). PlayerCallback也来自AACDecoder库: https://github.com/vbartacek/aacdecoder-android/blob/b58c519a341340a251f3291895c76ff63aef5b94/decoder/src/com/spoledge/aacdecoder/PlayerCallback.java

Now IcyInputStream can catch the medatada and invoke callback object (playerCallback here). PlayerCallback is also from the AACDecoder library: https://github.com/vbartacek/aacdecoder-android/blob/b58c519a341340a251f3291895c76ff63aef5b94/decoder/src/com/spoledge/aacdecoder/PlayerCallback.java

这样，您就不会制作任何重复的流，并且它是单数的.如果您不想在项目中使用AACDecoder库，则只需复制所需的文件，然后将其直接包含在项目中即可.

This way you are not making any duplicate stream and it is singular. If you don't want to have AACDecoder library in your project, then you can just copy needed files and include them directly in your project.

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