Exoplayer 2 java.io.IOException：许可证获取期间出错

Question

我正在尝试播放受DRM保护的流URL，并出现以下错误。

Caused by: com.google.android.exoplayer2.drm.DrmSession$DrmSessionException: java.io.IOException: Error during license acquisition
    at com.google.android.exoplayer2.drm.DefaultDrmSession.onError(DefaultDrmSession.java:422)
    at com.google.android.exoplayer2.drm.DefaultDrmSession.onKeysError(DefaultDrmSession.java:417)
    at com.google.android.exoplayer2.drm.DefaultDrmSession.onKeyResponse(DefaultDrmSession.java:379)
    at com.google.android.exoplayer2.drm.DefaultDrmSession.access$100(DefaultDrmSession.java:41)
    at com.google.android.exoplayer2.drm.DefaultDrmSession$PostResponseHandler.handleMessage(DefaultDrmSession.java:472)
    at android.os.Handler.dispatchMessage(Handler.java:102)
    at android.os.Looper.loop(Looper.java:148) 
    at android.os.HandlerThread.run(HandlerThread.java:61) 
 Caused by: java.io.IOException: Error during license acquisition
    at com.osolutions.otv.movie.exoplayer.ExoplayerActivity$1.executeKeyRequest(ExoplayerActivity.java:216)
    at com.google.android.exoplayer2.drm.DefaultDrmSession$PostRequestHandler.handleMessage(DefaultDrmSession.java:503)
    at android.os.Handler.dispatchMessage(Handler.java:102) 
    at android.os.Looper.loop(Looper.java:148) 
    at android.os.HandlerThread.run(HandlerThread.java:61) 
 Caused by: com.google.android.exoplayer2.upstream.HttpDataSource$InvalidResponseCodeException: Response code: 400
    at com.google.android.exoplayer2.upstream.DefaultHttpDataSource.open(DefaultHttpDataSource.java:211)
    at com.google.android.exoplayer2.upstream.DataSourceInputStream.checkOpened(DataSourceInputStream.java:102)
    at com.google.android.exoplayer2.upstream.DataSourceInputStream.read(DataSourceInputStream.java:82)
    at com.google.android.exoplayer2.upstream.DataSourceInputStream.read(DataSourceInputStream.java:76)
    at com.google.android.exoplayer2.util.Util.toByteArray(Util.java:128)
    at com.osolutions.otv.movie.exoplayer.ExoplayerActivity.executePost(ExoplayerActivity.java:253)
    at com.osolutions.otv.movie.exoplayer.ExoplayerActivity.access$000(ExoplayerActivity.java:77)
    at com.osolutions.otv.movie.exoplayer.ExoplayerActivity$1.executeKeyRequest(ExoplayerActivity.java:212)
    at com.google.android.exoplayer2.drm.DefaultDrmSession$PostRequestHandler.handleMessage(DefaultDrmSession.java:503) 
    at android.os.Handler.dispatchMessage(Handler.java:102) 
    at android.os.Looper.loop(Looper.java:148) 
    at android.os.HandlerThread.run(HandlerThread.java:61) 

我将MediaDrmCallback用作：

 MediaDrmCallback mediaDrmCallback = new MediaDrmCallback() {
    @Override
    public byte[] executeProvisionRequest(UUID uuid, ExoMediaDrm.ProvisionRequest request) throws Exception {
        String url = request.getDefaultUrl() + "&signedRequest=" + new String(request.getData());
        return executePost(url, null, null);
        //return executePost(dataSourceFactory, url, null, null);
    }

    @Override
    public byte[] executeKeyRequest(UUID uuid, ExoMediaDrm.KeyRequest request) throws Exception {

        //Holder for additional req parameters, as per custom implementation
        Map<String, String> requestProperties = new HashMap<>();
        Uri.Builder builder = Uri.parse(DRM_LICENSE_URL).buildUpon();

        // Set content type for Widevine
        requestProperties.put("Content-Type", "text/xml");

        Uri uri = builder.build();
        try {
            return executePost(uri.toString(), request.getData(), requestProperties);
        } catch (FileNotFoundException e) {
            throw new IOException("License not found");
        } catch (IOException e) {
            throw new IOException("Error during license acquisition", e);
        }

    }
};

如果我将以下内容替换为executeKeyRequest方法，则该方法有效，并且在这段时间内，我只能播放视频9秒钟。

public byte[] executeKeyRequest(UUID uuid, ExoMediaDrm.KeyRequest request) throws Exception {

            try {
                flag = false;
                String payload = Base64.encodeToString(request.getData(), Base64.DEFAULT);

                LogCS.e("payload", payload.trim().replaceAll("\n", ""));

                DRMLicensePresenterImpl drmLicensePresenter = new DRMLicensePresenterImpl(ExoplayerActivity.this, ExoplayerActivity.this, payload.trim().replaceAll("\n", ""), ticketToStream);
                drmLicensePresenter.getDRMLicenseDetail(UrlUtil.getAltBalajiUrl(ExoplayerActivity.this, UrlUtil.DRM_LICENSE));

            } catch (Exception e) {
                e.printStackTrace();
            }
            LogCS.e("license is" + count++ + "----", license);


        // get license
       return Base64.decode(license, Base64.DEFAULT);

    }

我真的很麻烦。任何帮助将不胜感激。