android - 使用Exoplayer从Icecast流中提取元数据

自从从mediaplayer切换到一个简单的exoplayer实现之后，我注意到加载时间有了很大的提高，但我想知道是否有任何内置功能，比如流式音频时的元数据更改侦听器？
我用一个简单的例子实现了exoplayer，如下所示：

    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);

最佳答案

我有一个异步任务，它从一个Icecast流启动exoplayer：

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作为请求的响应。我从aacdecoder库https://github.com/vbartacek/aacdecoder-android/blob/master/decoder/src/com/spoledge/aacdecoder/IcyInputStream.java中包含了这个类，并根据响应将inputstream替换为icyinputstream：
（在OkhttpDataSource的open（）中）

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（这里是playercallback）。playercallback也来自aacdecoder库：https://github.com/vbartacek/aacdecoder-android/blob/b58c519a341340a251f3291895c76ff63aef5b94/decoder/src/com/spoledge/aacdecoder/PlayerCallback.java
这样就不会产生任何重复的流，而且它是单数的。如果您不想在项目中包含aacdecoder库，则只需复制所需的文件并将其直接包含在项目中。