Java BandwidthMeter.NO_ESTIMATE属性代码示例

private int getVariantIndexForBandwidth(long bitrateEstimate) {
  if (bitrateEstimate == BandwidthMeter.NO_ESTIMATE) {
    // Select the lowest quality.
    bitrateEstimate = 0;
  }
  int effectiveBitrate = (int) (bitrateEstimate * BANDWIDTH_FRACTION);
  int lowestQualityEnabledVariantIndex = -1;
  for (int i = 0; i < variants.length; i++) {
    if (variantBlacklistTimes[i] == 0) {
      if (variants[i].format.bitrate <= effectiveBitrate) {
        return i;
      }
      lowestQualityEnabledVariantIndex = i;
    }
  }
  // At least one variant should always be enabled.
  Assertions.checkState(lowestQualityEnabledVariantIndex != -1);
  return lowestQualityEnabledVariantIndex;
}
 

private int getNextVariantIndex(TsChunk previousTsChunk, long playbackPositionUs) {
  clearStaleBlacklistedVariants();
  long bitrateEstimate = bandwidthMeter.getBitrateEstimate();
  if (variantBlacklistTimes[selectedVariantIndex] != 0) {
    // The current variant has been blacklisted, so we have no choice but to re-evaluate.
    return getVariantIndexForBandwidth(bitrateEstimate);
  }
  if (previousTsChunk == null) {
    // Don't consider switching if we don't have a previous chunk.
    return selectedVariantIndex;
  }
  if (bitrateEstimate == BandwidthMeter.NO_ESTIMATE) {
    // Don't consider switching if we don't have a bandwidth estimate.
    return selectedVariantIndex;
  }
  int idealIndex = getVariantIndexForBandwidth(bitrateEstimate);
  if (idealIndex == selectedVariantIndex) {
    // We're already using the ideal variant.
    return selectedVariantIndex;
  }
  // We're not using the ideal variant for the available bandwidth, but only switch if the
  // conditions are appropriate.
  long bufferedPositionUs = adaptiveMode == ADAPTIVE_MODE_SPLICE ? previousTsChunk.startTimeUs
      : previousTsChunk.endTimeUs;
  long bufferedUs = bufferedPositionUs - playbackPositionUs;
  if (variantBlacklistTimes[selectedVariantIndex] != 0
      || (idealIndex > selectedVariantIndex && bufferedUs < maxBufferDurationToSwitchDownUs)
      || (idealIndex < selectedVariantIndex && bufferedUs > minBufferDurationToSwitchUpUs)) {
    // Switch variant.
    return idealIndex;
  }
  // Stick with the current variant for now.
  return selectedVariantIndex;
}
 

/**
 * Compute the ideal format ignoring buffer health.
 */
private Format determineIdealFormat(Format[] formats, long bitrateEstimate) {
  long effectiveBitrate = bitrateEstimate == BandwidthMeter.NO_ESTIMATE
      ? maxInitialBitrate : (long) (bitrateEstimate * bandwidthFraction);
  for (int i = 0; i < formats.length; i++) {
    Format format = formats[i];
    if (format.bitrate <= effectiveBitrate) {
      return format;
    }
  }
  // We didn't manage to calculate a suitable format. Return the lowest quality format.
  return formats[formats.length - 1];
}
 

private String getBandwidthString() {
  BandwidthMeter bandwidthMeter = debuggable.getBandwidthMeter();
  if (bandwidthMeter == null
      || bandwidthMeter.getBitrateEstimate() == BandwidthMeter.NO_ESTIMATE) {
    return "bw:?";
  } else {
    return "bw:" + (bandwidthMeter.getBitrateEstimate() / 1000);
  }
}
 

/**
 * Apply overhead factor, or default value in absence of estimate.
 */
protected long computeEffectiveBitrateEstimate(long bitrateEstimate) {
  return bitrateEstimate == BandwidthMeter.NO_ESTIMATE
      ? maxInitialBitrate : (long) (bitrateEstimate * bandwidthFraction);
}