ABRConfiguration.ts

import { Resolution } from '../resolution/Resolution';

/**
 * The adaptive bitrate strategy of the first segment, represented by a value from the following list:
 * <br/> - `'performance'`: The player will optimize ABR behavior to focus on the performance of the player. This strategy initiates playback with the lowest quality suitable for the device which means faster start-up time.
 * <br/> - `'quality'`: The player will optimize ABR behavior to focus displaying the best visual quality to the end-user. This strategy initiates playback with the highest bit rate suitable for the device.
 * <br/> - `'bandwidth'`: The player will optimize the ABR behavior to focus on displaying the most optimal quality based on historic data of available bandwidth and knowledge of the network conditions.
 *
 * @public
 */
export enum ABRStrategyType {
  performance = 'performance',
  quality = 'quality',
  bandwidth = 'bandwidth',
}

/**
 * Describes the metadata of the adaptive bitrate strategy.
 *
 * @public
 */
export interface ABRMetadata {
  /**
   * The initial bitrate, in bits per second.
   *
   * @defaultValue Bitrate available to the browser.
   */
  bitrate?: number;
}

/**
 * Describes the configuration of the adaptive bitrate strategy.
 *
 * @public
 */
export interface ABRStrategyConfiguration {
  /**
   * The strategy for initial playback.
   */
  type: ABRStrategyType;

  /**
   * The metadata for the initial playback strategy.
   *
   * @defaultValue A {@link ABRMetadata} object with default values.
   */
  metadata?: ABRMetadata;
}

/**
 * The adaptive bitrate stratey.
 *
 * @public
 */
export type ABRStrategy = ABRStrategyConfiguration | ABRStrategyType;

/**
 * Describes the adaptive bitrate configuration.
 *
 * @public
 */
export interface ABRConfiguration {
  /**
   * The adaptive bitrate strategy.
   *
   * @defaultValue `'bandwidth'`
   * @remarks
   * <br/> - This property is currently supported on Web and Android platforms only.
   */
  strategy?: ABRStrategy;

  /**
   * The amount which the player should buffer ahead of the current playback position, in seconds.
   *
   * @remarks
   * <br/> - Before v4.3.0: This duration has a maximum of 60 seconds.
   * <br/> - After v4.3.0: This duration has no maximum.
   * <br/> - The player might reduce or ignore the configured amount because of device or performance constraints.
   *
   * @defaultValue `20`
   */
  targetBuffer?: number;

  /**
   * The amount of data which the player should keep in its buffer before the current playback position, in seconds.
   * This configuration option can be used to reduce the memory footprint on memory restricted devices or on devices
   * which don't automatically prune decoder buffers.
   *
   * Note that the player can decide to keep less data in the decoder buffer in case memory is running low.
   * A value of 0 or lower is not accepted and will be treated as default.
   *
   * @defaultValue `30`
   *
   * @remarks
   * <br/> - This property is currently supported on Web platforms only.
   */
  bufferLookbackWindow?: number;

  /**
   * The maximum length of the player's buffer, in seconds.
   *
   * The player will initially buffer up to {@link ABRConfiguration.targetBuffer} seconds of media data.
   * If the player detects that the decoder is unable to hold so much data,
   * it will reduce `maxBufferLength` and restrict `targetBuffer` to be less than
   * this maximum.
   *
   * @remarks
   * <br/> - This property is currently supported on Web platforms only.
   */
  readonly maxBufferLength?: number;

  /**
   * The desired limit of network bandwidth consumption for this item.
   *
   * Set preferredPeakBitRate to non-zero to indicate that the player should attempt to limit item playback to that bit rate, expressed in bits per second.
   * If network bandwidth consumption cannot be lowered to meet the preferredPeakBitRate, it will be reduced as much as possible while continuing to play the item.
   *
   * @remarks
   * <br/> - This property is supported on iOS platforms only.
   */
  preferredPeakBitRate?: number;

  /**
   * A preferred upper limit on the resolution of the video to be downloaded (or otherwise transferred) and rendered by the player.
   *
   * The default value is (0,0), which indicates that the client enforces no limit on video resolution. Other values indicate a preferred maximum video resolution.
   * It only applies to HTTP Live Streaming asset.
   *
   * @remarks
   * <br/> - This property is supported on iOS platforms only.
   */
  preferredMaximumResolution?: Resolution;
}