在ExoPlayer中使用缓存

Question

我正在寻找在ExoPlayer中实现缓存的任何示例.

ExoPlayer在其库中有不同的缓存类,Google在此视频中解释我们可以使用CacheDataSource类实现它,但Google不提供任何演示.不幸的是,这看起来相当复杂,所以我目前正在寻找示例(在Google上没有成功).

有没有人成功或有任何有用的信息？谢谢.

Answer 1

这是ExoPlayer 2的解决方案.+

创建自定义缓存数据源工厂

class CacheDataSourceFactory implements DataSource.Factory {
    private final Context context;
    private final DefaultDataSourceFactory defaultDatasourceFactory;
    private final long maxFileSize, maxCacheSize;

    CacheDataSourceFactory(Context context, long maxCacheSize, long maxFileSize) {
        super();
        this.context = context;
        this.maxCacheSize = maxCacheSize;
        this.maxFileSize = maxFileSize;
        String userAgent = Util.getUserAgent(context, context.getString(R.string.app_name));
        DefaultBandwidthMeter bandwidthMeter = new DefaultBandwidthMeter();
        defaultDatasourceFactory = new DefaultDataSourceFactory(this.context,
                bandwidthMeter,
                new DefaultHttpDataSourceFactory(userAgent, bandwidthMeter));
    }

    @Override
    public DataSource createDataSource() {
        LeastRecentlyUsedCacheEvictor evictor = new LeastRecentlyUsedCacheEvictor(maxCacheSize);
        SimpleCache simpleCache = new SimpleCache(new File(context.getCacheDir(), "media"), evictor);
        return new CacheDataSource(simpleCache, defaultDatasourceFactory.createDataSource(),
                new FileDataSource(), new CacheDataSink(simpleCache, maxFileSize),
                CacheDataSource.FLAG_BLOCK_ON_CACHE | CacheDataSource.FLAG_IGNORE_CACHE_ON_ERROR, null);
    }
}

和玩家

BandwidthMeter bandwidthMeter = new DefaultBandwidthMeter();
TrackSelection.Factory videoTrackSelectionFactory =
        new AdaptiveTrackSelection.Factory(bandwidthMeter);
TrackSelector trackSelector = new DefaultTrackSelector(videoTrackSelectionFactory);

SimpleExoPlayer exoPlayer = ExoPlayerFactory.newSimpleInstance(this, trackSelector);
MediaSource audioSource = new ExtractorMediaSource(Uri.parse(url),
            new CacheDataSourceFactory(context, 100 * 1024 * 1024, 5 * 1024 * 1024), new DefaultExtractorsFactory(), null, null);
exoPlayer.setPlayWhenReady(true); 
exoPlayer.prepare(audioSource);

它工作得很好.

Answer 2

默认情况下，ExoPlayer不缓存媒体（视频，音频等）。例如，如果您要播放在线视频文件，则ExoPlayer每次打开连接时，先读取数据然后播放。

幸运的是，它为我们提供了一些接口和实现类，以支持我们应用程序中的缓存媒体。

您可以编写自己的缓存，以实现ExoPlayer中的给定接口。为简单起见，我将指导您如何使用实现类启用缓存。

步骤1：指定一个包含媒体文件的文件夹，在Android中，对于较小的缓存文件夹（小于1MB），您应该使用 getCacheDir，否则可以指定首选的缓存文件夹，例如getFileDir。

步骤2： 为缓存文件夹指定大小，并在达到大小时指定策略。有2个API

• NoOpCacheEvictor永远不会逐出/删除缓存文件。根据缓存文件夹的位置（如果它位于内部存储中），当用户清除应用程序数据或卸载应用程序时，该文件夹将被删除。
• LeastRecentlyUsedCacheEvictor，它将首先逐出/删除最近最少使用的缓存文件。例如，如果您的缓存大小为10MB，则在达到该大小时，它将自动查找并删除最近最少使用的文件。

把它放在一起

val renderersFactory = DefaultRenderersFactory(context.applicationContext)
val trackSelector = DefaultTrackSelector()
val loadControl = DefaultLoadControl()

val player = ExoPlayerFactory.newSimpleInstance(context, renderersFactory, trackSelector, loadControl)
player.addListener(this)

// Specify cache folder, my cache folder named media which is inside getCacheDir.
val cacheFolder = File(context.cacheDir, "media")

// Specify cache size and removing policies
val cacheEvictor = LeastRecentlyUsedCacheEvictor(1 * 1024 * 1024) // My cache size will be 1MB and it will automatically remove least recently used files if the size is reached out.

// Build cache
val cache = SimpleCache(cacheFolder, cacheEvictor)

// Build data source factory with cache enabled, if data is available in cache it will return immediately, otherwise it will open a new connection to get the data.
val cacheDataSourceFactory = CacheDataSourceFactory(cache, DefaultHttpDataSourceFactory("ExoplayerDemo"))

val uri = Uri.parse("Put your media url here")
val mediaSource = ExtractorMediaSource.Factory(cacheDataSourceFactory).createMediaSource(uri)

player.prepare(mediaSource)

Answer 3

我在这里回答了这个类似的问题：https : //stackoverflow.com/a/58678192/2029134

基本上，我使用这个库：https : //github.com/danikula/AndroidVideoCache 从 URL 缓存文件，然后将其放入 ExoPlayer。

这是示例代码：

String mediaURL = "https://my_cool_vid.com/vi.mp4";
SimpleExoPlayer exoPlayer = ExoPlayerFactory.newSimpleInstance(getContext());
HttpProxyCacheServer proxyServer = HttpProxyCacheServer.Builder(getContext()).maxCacheSize(1024 * 1024 * 1024).build();

String proxyURL = proxyServer.getProxyUrl(mediaURL);


DataSource.Factory dataSourceFactory = new DefaultDataSourceFactory(getContext(),
                Util.getUserAgent(getContext(), getActivity().getApplicationContext().getPackageName()));


exoPlayer.prepare(new ProgressiveMediaSource.Factory(dataSourceFactory)
                .createMediaSource(Uri.parse(proxyURL)););

希望有帮助。

Answer 4

要解决多个视频或进程尝试访问同一个缓存的问题，您需要一个真正的 Singleton。一种可靠的方法是这样做：

object VideoCache {
    private var sDownloadCache: SimpleCache? = null
    private const val maxCacheSize: Long = 100 * 1024 * 1024

    fun getInstance(context: Context): SimpleCache {
        val evictor = LeastRecentlyUsedCacheEvictor(maxCacheSize)
        if (sDownloadCache == null) sDownloadCache = SimpleCache(File(context.cacheDir, "koko-media"), evictor)
        return sDownloadCache as SimpleCache
    }
}

您现在可以使用：

private val simpleCache: SimpleCache by lazy {
        VideoCache.getInstance(context)
    }

Answer 5

这是一个用OkHttp替换演示数据源的示例,默认是没有缓存 https://github.com/b95505017/ExoPlayer/commit/ebfdda8e7848a2e2e275f5c0525f614b56ef43a6 https://github.com/b95505017/ExoPlayer/tree/okhttp_http_data_source 所以,你只是需要正确配置OkHttp缓存并缓存请求.

Answer 6

我在渲染器构建器中像这样实现了它

private static final int BUFFER_SEGMENT_SIZE = 64 * 1024;
private static final int BUFFER_SEGMENT_COUNT = 160;

final String userAgent = Util.getUserAgent(mContext, appName);
final DefaultBandwidthMeter bandwidthMeter = new DefaultBandwidthMeter();
final Allocator allocator = new DefaultAllocator(BUFFER_SEGMENT_SIZE);*

Cache cache = new SimpleCache(context.getCacheDir(), new LeastRecentlyUsedCacheEvictor(1024 * 1024 * 10));
DataSource dataSource = new DefaultUriDataSource(context, bandwidthMeter, userAgent);
CacheDataSource cacheDataSource = new CacheDataSource(cache, dataSource, false, false);
ExtractorSampleSource sampleSource = new ExtractorSampleSource(uri
                , cacheDataSource
                , allocator
                , BUFFER_SEGMENT_COUNT * BUFFER_SEGMENT_SIZE
                , new Mp4Extractor());