ExaPlayer2 DRM异常shouldWaitForKeys

Question

    protected DrmSessionManager<FrameworkMediaCrypto> generateDrmSessionManager() {
        // DRM is only supported on API 18 + in the ExoPlayer
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN_MR2) {
            return null;
        }

        // Widevine will capture the majority of use cases however playready is supported on all AndroidTV devices
        UUID uuid = C.WIDEVINE_UUID;
        final String licenseURL = "http://video.aaa";

        HttpMediaDrmCallback drmCallback =
                new HttpMediaDrmCallback(
                        licenseURL, buildHttpDataSourceFactory(false), KEY_REQUEST_PROPERTIES);

        try {
            return new DefaultDrmSessionManager<>(
                    uuid, FrameworkMediaDrm.newInstance(uuid), drmCallback, null, mainHandler, capabilitiesListener);
        } catch (Exception e) {
            Log.d(TAG, "Unable to create a DrmSessionManager due to an exception", e);
            return null;
        }
    }

executePost(dataSourceFactory, url, request.getData(), requestProperties);

HttpDataSource dataSource = dataSourceFactory.createDataSource();

我不知道它为什么会崩溃，因为在我的ExoPlayer1.x实现中工作良好。

Answer 1

此异常是由于userAgent字符串在此处为空或零长度导致的：

public DefaultHttpDataSource(String userAgent, Predicate<String> contentTypePredicate,
      TransferListener<? super DefaultHttpDataSource> listener, int connectTimeoutMillis,
      int readTimeoutMillis, boolean allowCrossProtocolRedirects,
      RequestProperties defaultRequestProperties) {
    this.userAgent = Assertions.checkNotEmpty(userAgent);  <---- Exception is here
    this.contentTypePredicate = contentTypePredicate;
    this.listener = listener;
    this.requestProperties = new RequestProperties();
    this.connectTimeoutMillis = connectTimeoutMillis;
    this.readTimeoutMillis = readTimeoutMillis;
    this.allowCrossProtocolRedirects = allowCrossProtocolRedirects;
    this.defaultRequestProperties = defaultRequestProperties;
  }

userAgent是应用程序名称和ExoPlayer库版本的组合：

/**
   * Returns a user agent string based on the given application name and the library version.
   *
   * @param context A valid context of the calling application.
   * @param applicationName String that will be prefix'ed to the generated user agent.
   * @return A user agent string generated using the applicationName and the library version.
   */
  public static String getUserAgent(Context context, String applicationName) {
    String versionName;
    try {
      String packageName = context.getPackageName();
      PackageInfo info = context.getPackageManager().getPackageInfo(packageName, 0);
      versionName = info.versionName;
    } catch (NameNotFoundException e) {
      versionName = "?";
    }
    return applicationName + "/" + versionName + " (Linux;Android " + Build.VERSION.RELEASE
        + ") " + ExoPlayerLibraryInfo.VERSION_SLASHY;
  }

您可以在演示应用程序https://github.com/google/exoplayer/tree/release-v2/demo中看到它的使用和设置示例

// Measures bandwidth during playback. Can be null if not required.
DefaultBandwidthMeter bandwidthMeter = new DefaultBandwidthMeter();
// Produces DataSource instances through which media data is loaded.
DataSource.Factory dataSourceFactory = new DefaultDataSourceFactory(context,
    Util.getUserAgent(context, "yourApplicationName"), bandwidthMeter);
// Produces Extractor instances for parsing the media data.
ExtractorsFactory extractorsFactory = new DefaultExtractorsFactory();
// This is the MediaSource representing the media to be played.
MediaSource videoSource = new ExtractorMediaSource(mp4VideoUri,
    dataSourceFactory, extractorsFactory, null, null);
// Prepare the player with the source.
player.prepare(videoSource);