實現封鎖處理

TVSDK提供API和示例代碼以處理封鎖期。

要實現封鎖處理，包括在封鎖期間提供備用內容：

  1. 設定應用以檢測即時流清單中的封鎖標籤。

    public void createMediaPlayer {
    ...
    String[] blackoutTags = {BLACKOUTTAG};
    PSDKConfig.setSubscribedTags(blackoutTags);
    // For example: PTSDKConfig.setSubscribedTags({"#EXT-OATCLS-SCTE35"});
}

  2. 為前台流和後台流中的定時元資料事件建立事件偵聽器。

    private MediaPlayer createMediaPlayer() {
    mediaPlayer.addEventListener(MediaPlayer.Event.PLAYBACK, _playbackEventListener);
    mediaPlayer.addEventListener(MediaPlayer.Event.BLACKOUTS, _blackoutsEventListener);
}

  3. 為前台流和後台流實現定時元資料事件處理程式。

    前景：

    private final MediaPlayer.PlaybackEventListener _playbackEventListener =
          new MediaPlayer.PlaybackEventListener() {
    ...

    @override
    public void onTimedMetadata(TimedMetadata timedMetadata) {
        if (timedMetadata.getName().equal(BLACKOUTTAG) &&
            !_timedMetadataList.contains(timedMetadata)) {
              _timedMetadataList.add(timedMetadata);
        }
    }
    ...
}

private final MediaPlayer.BlackoutsEventListener _blackoutsEventListener =
  new MediaPlayer.BlackoutsEventListener() {
    @Override
    public void onTimedMetadataInBackgroundItem(TimedMetadata timedMetadata) {
        TimedMetadata.Type type = timedMetadata.getType();
        if (type.equals(TimedMetadata.Type.TAG) && _mediaPlayer.getPlaybackRange() != null
            && _mediaPlayer.getPlaybackRange().getDuration() > 0) {
            if (!_timedMetadataList.contains(timedMetadata) && isBlackoutMetadata(timedMetadata)) {
                _timedMetadataList.add(timedMetadata);
            }
        }
    }

    @Override
    public void onBackgroundManifestFailed() {
        ...
    }
};

  4. 手柄 TimedMetadata 對象 MediaPlayer 時間。

    _playbackClockEventListener = new Clock.ClockEventListener() {
    @Override
    public void onTick(String name) {
        getActivity().runOnUiThread(new Runnable() {
            @Override
            public void run() {
                /* handle timedmetadata object list  */
                if (_mediaPlayer != null && _timedMetadataList != null
                    && _timedMetadataList.size() > 0) {
                    if (_lastKnownStatus == MediaPlayer.PlayerState.PLAYING) {
                        long localTime = _mediaPlayer.getLocalTime();
                        handleTimedMetadataList(localTime);
                    }
                }
            }
        });
    }
};

  5. 建立用於在封鎖期開始和結束時切換內容的方法。

    private void handleTimedMetadataList(long currentTime) {
    for (int i = 0; i < _timedMetadataList.size(); i++) {
        TimedMetadata timedMetadata = _timedMetadataList.get(i);
        long diff = localTime - timedMetadata.getTime();
        if (!_timedMetadataDispatchedList.contains(timedMetadata)
            && diff >= 0
            && diff <= PLAYBACK_CLOCK_INTERVAL
            && _mediaPlayer.shouldTriggerSubscribedTagEvent()) {
                // switch to blackout content
            if (!_inBlackout && isBlackoutStartTimedMetadata(timedMetadata)) {
                MediaResource blackoutMediaResource = createBlackoutMediaResource(timedMetadata);

                //1. register current item as background item
                _mediaPlayer.registerCurrentItemAsBackgroundItem();

                //2. replace current item with blackout item
                _mediaPlayer.replaceCurrentItem(blackoutMediaResource);

                //3. update qos metrics
                _mediaQosProvider.updateMetrics(_mediaPlayer);

                //4. maintain state
                _inBlackout = true;
                resetTimedMetada();

                break;
            }
            // switch back to main content
            else if (_inBlackout && isBlackoutEndTimedMetadata(timedMetadata)) {
                //1. register current item as background item
                _mediaPlayer.unregisterCurrentBackgroundItem();

                //2. replace current item with blackout item
                _mediaPlayer.replaceCurrentItem(_oldMediaResource);

                //3. update qos metrics
                _mediaQosProvider.updateMetrics(_mediaPlayer);

                //4. maintain state
                _inBlackout = false;
                resetTimedMetada();

                break;
            }
        }
    }
}

  6. 如果封鎖範圍在播放流的DVR中，則更新不可查找的範圍。

    // prepare and update blackout nonSeekable ranges

List<TimeRange> blackoutRanges = prepareBlackoutRanges(_timedMetadataList);
if (blackoutRanges != null && blackoutRanges.size() > 0) {
    int size = blackoutRanges.size();
    TimeRange[] blackoutRangesArray = blackoutRanges.toArray(new TimeRange[size]);
    BlackoutMetadata blackoutMetadata = new BlackoutMetadata(blackoutRangesArray);
    updateBlackoutMetadata(blackoutMetadata);
}

// function to update blackout metadata
private void updateBlackoutMetadata(BlackoutMetadata blackoutMetadata) {
    MediaPlayerItem currentItem = _mediaPlayer.getCurrentItem();
    if (currentItem != null) {
        Metadata metadata = currentItem.getResource().getMetadata();
        if (metadata != null) {
            MetadataNode metadataNode = ((MetadataNode) metadata);
            metadataNode.setNode(DefaultMetadataKeys.BLACKOUT_METADATA_KEY.getValue(),
                                 blackoutMetadata);

            for (int i = 0; i < blackoutMetadata.getNonSeekableRanges().length; i++) {
                TimeRange timeRange = blackoutMetadata.getNonSeekableRanges()[i];
            }
        }
    }
}
    注意

    目前，對於多位率即時流，有時可調位率(ABR)配置檔案會失去同步。 這會導致重複 timedMetadata 同一訂閱標籤的對象。 為避免不正確的不可瀏覽計算，強烈建議在計算後檢查重疊的不可瀏覽範圍，如下例所示：

    List<TimeRange> rangesToRemove = new ArrayList<TimeRange>();

for (int i = 0; i < nonSeekableRanges.size() - 1; i++) {
    TimeRange range1 = nonSeekableRanges.get(i);
    TimeRange range2 = nonSeekableRanges.get(i + 1);
    if (range1.contains(range2.getBegin()) && !rangesToRemove.contains(range2)) {
       rangesToRemove.add(range2);
    } else if (range2.contains(range1.getBegin()) && !rangesToRemove.contains(range1)) {
       rangesToRemove.add(range1);
   }
}

if (nonSeekableRanges.size() > 0 && rangesToRemove.size() > 0) {
    nonSeekableRanges.removeAll(rangesToRemove);
    for (int i = 0; i < rangesToRemove.size(); i++) {
        TimeRange range = rangesToRemove.get(i);
    }
}

if (nonSeekableRanges.size() > 0 && rangesToRemove.size() > 0) {
    nonSeekableRanges.removeAll(rangesToRemove);
}

本頁內容