Dash JS

Module: Settings

Define the configuration parameters of Dash.js MediaPlayer.

Source:
See:
  • PlayerSettings for further information about the supported configuration properties

Type Definitions

AbrSettings

Type:
  • Object
Properties:
Name Type Argument Default Description
movingAverageMethod string <optional>
 "slidingWindow"

Sets the moving average method used for smoothing throughput estimates. Valid methods are "slidingWindow" and "ewma". The call has no effect if an invalid method is passed.

The sliding window moving average method computes the average throughput using the last four segments downloaded. If the stream is live (as opposed to VOD), then only the last three segments are used. If wide variations in throughput are detected, the number of segments can be dynamically increased to avoid oscillations.

The exponentially weighted moving average (EWMA) method computes the average using exponential smoothing. Two separate estimates are maintained, a fast one with a three-second half life and a slow one with an eight-second half life. The throughput estimate at any time is the minimum of the fast and slow estimates. This allows a fast reaction to a bandwidth drop and prevents oscillations on bandwidth spikes.
ABRStrategy string <optional>
 "abrDynamic"

Returns the current ABR strategy being used: "abrDynamic", "abrBola" or "abrThroughput".
bandwidthSafetyFactor number <optional>
 0.9

Standard ABR throughput rules multiply the throughput by this value. It should be between 0 and 1, with lower values giving less rebuffering (but also lower quality).
useDefaultABRRules boolean <optional>
 true

Should the default ABR rules be used, or the custom ones added.
useDeadTimeLatency boolean <optional>
 true

If true, only the download portion will be considered part of the download bitrate and latency will be regarded as static. If false, the reciprocal of the whole transfer time will be used.
limitBitrateByPortal boolean <optional>
 false

If true, the size of the video portal will limit the max chosen video resolution.
usePixelRatioInLimitBitrateByPortal boolean <optional>
 false

Sets whether to take into account the device's pixel ratio when defining the portal dimensions. Useful on, for example, retina displays.
maxBitrate module:Settings~AudioVideoSettings <optional>
 {audio: -1, video: -1}

The maximum bitrate that the ABR algorithms will choose. Use NaN for no limit.
minBitrate module:Settings~AudioVideoSettings <optional>
 {audio: -1, video: -1}

The minimum bitrate that the ABR algorithms will choose. Use NaN for no limit.
maxRepresentationRatio module:Settings~AudioVideoSettings <optional>
 {audio: 1, video: 1}

When switching multi-bitrate content (auto or manual mode) this property specifies the maximum representation allowed, as a proportion of the size of the representation set.

You can set or remove this cap at anytime before or during playback. To clear this setting you set the value to 1.

If both this and maxAllowedBitrate are defined, maxAllowedBitrate is evaluated first, then maxAllowedRepresentation, i.e. the lowest value from executing these rules is used.

This feature is typically used to reserve higher representations for playback only when connected over a fast connection.
initialBitrate module:Settings~AudioVideoSettings <optional>
 {audio: -1, video: -1}

Explicitly set the starting bitrate for audio or video
initialRepresentationRatio module:Settings~AudioVideoSettings <optional>
 {audio: -1, video: -1}

Explicitly set the initial representation ratio. If initalBitrate is specified, this is ignored.
autoSwitchBitrate module:Settings~AudioVideoSettings <optional>
 {audio: true, video: true}

Indicates whether the player should enable ABR algorithms to switch the bitrate.
fetchThroughputCalculationMode boolean <optional>
 Constants.ABR_FETCH_THROUGHPUT_CALCULATION_DOWNLOADED_DATA

Algorithm to determine the throughput in case the Fetch API is used for low latency streaming. For details please check the samples section and FetchLoader.js
Source:

AudioVideoSettings

Type:
  • Object
Properties:
Name Type Argument Description
audio number | boolean <optional>

Configuration for audio media type of tracks.
video number | boolean <optional>

Configuration for video media type of tracks.
Source:

CachingInfoSettings

Type:
  • Object
Properties:
Name Type Argument Description
enable boolean <optional>

Enable or disable the caching feature.
ttl number <optional>

Time to live. A value defined in milliseconds representing how log to cache the settings for.
Source:

CmcdSettings

Type:
  • Object
Properties:
Name Type Argument Default Description
enable boolean <optional>
 false

Enable or disable the CMCD reporting.
sid string <optional>

GUID identifying the current playback session. Should be in UUID format. If not specified a UUID will be automatically generated.
cid string <optional>

A unique string to identify the current content. If not specified it will be a hash of the MPD url.
did string <optional>
 dash.js-cmcd-default-id

A unique string identifying the current device.
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DebugSettings

Type:
  • Object
Properties:
Name Type Argument Default Description
logLevel number <optional>
 dashjs.Debug.LOG_LEVEL_WARNING

Sets up the log level. The levels are cumulative. For example, if you set the log level to dashjs.Debug.LOG_LEVEL_WARNING all warnings, errors and fatals will be logged. Possible values.

  • dashjs.Debug.LOG_LEVEL_NONE
    No message is written in the browser console.
  • dashjs.Debug.LOG_LEVEL_FATAL
    Log fatal errors. An error is considered fatal when it causes playback to fail completely.
  • dashjs.Debug.LOG_LEVEL_ERROR
    Log error messages.
  • dashjs.Debug.LOG_LEVEL_WARNING
    Log warning messages.
  • dashjs.Debug.LOG_LEVEL_INFO
    Log info messages.
  • dashjs.Debug.LOG_LEVEL_DEBUG
    Log debug messages.
dispatchEvent boolean <optional>
 false

Enable to trigger a Events.LOG event whenever log output is generated. Note this will be dispatched regardless of log level
Source:

LiveCatchupSettings

Type:
  • Object
Properties:
Name Type Argument Default Description
minDrift number <optional>
 0.02

Use this method to set the minimum latency deviation allowed before activating catch-up mechanism. In low latency mode, when the difference between the measured latency and the target one, as an absolute number, is higher than the one sets with this method, then dash.js increases/decreases playback rate until target latency is reached.

LowLatencyMinDrift should be provided in seconds, and it uses values between 0.0 and 0.5.

Note: Catch-up mechanism is only applied when playing low latency live streams.
maxDrift number <optional>
 0

Use this method to set the maximum latency deviation allowed before dash.js to do a seeking to live position. In low latency mode, when the difference between the measured latency and the target one, as an absolute number, is higher than the one sets with this method, then dash.js does a seek to live edge position minus the target live delay.

LowLatencyMaxDriftBeforeSeeking should be provided in seconds. If 0, then seeking operations won't be used for fixing latency deviations.

Note: Catch-up mechanism is only applied when playing low latency live streams.
playbackRate number <optional>
 0.5

Use this parameter to set the maximum catch up rate, as a percentage, for low latency live streams. In low latency mode, when measured latency is higher/lower than the target one, dash.js increases/decreases playback rate respectively up to (+/-) the percentage defined with this method until target is reached.

Valid values for catch up rate are in range 0-0.5 (0-50%). Set it to 0 to turn off live catch up feature.

Note: Catch-up mechanism is only applied when playing low latency live streams.
latencyThreshold number <optional>
 NaN

Use this parameter to set the maximum threshold for which live catch up is applied. For instance, if this value is set to 8 seconds, then live catchup is only applied if the current live latency is equal or below 8 seconds. The reason behind this parameter is to avoid an increase of the playback rate if the user seeks within the DVR window.

If no value is specified this will be twice the maximum live delay. The maximum live delay is either specified in the manifest as part of a ServiceDescriptor or calculated the following: maximumLiveDelay = targetDelay + liveCatchupMinDrift
playbackBufferMin number <optional>
 NaN

Use this parameter to specify the minimum buffer which is used for LoL+ based playback rate reduction
enabled boolean <optional>
 false

Use this parameter to enable the catchup mode for non low-latency streams
mode String <optional>
 Constants.LIVE_CATCHUP_MODE_DEFAULT

Use this parameter to switch between different catchup modes. Options: "liveCatchupModeDefault" or "liveCatchupModeLOLP"

Note: Catch-up mechanism is automatically applied when playing low latency live streams.
Source:

PlayerSettings

Type:
  • Object
Properties:
Name Type Argument Description
debug module:Settings~DebugSettings <optional>

Debug related settings
streaming module:Settings~StreamingSettings <optional>

Streaming related settings
Source:
Example
// Full settings object
settings = {
     debug: {
         logLevel: Debug.LOG_LEVEL_WARNING,
         dispatchEvent: false
     },
     streaming: {
         metricsMaxListDepth: 1000,
         abandonLoadTimeout: 10000,
         liveDelayFragmentCount: NaN,
         liveDelay: null,
         scheduleWhilePaused: true,
         fastSwitchEnabled: false,
         flushBufferAtTrackSwitch: false,
         calcSegmentAvailabilityRangeFromTimeline: false,
         reuseExistingSourceBuffers: true,
         bufferPruningInterval: 10,
         bufferToKeep: 20,
         jumpGaps: true,
         jumpLargeGaps: true,
         smallGapLimit: 1.5,
         stableBufferTime: 12,
         bufferTimeAtTopQuality: 30,
         bufferTimeAtTopQualityLongForm: 60,
         longFormContentDurationThreshold: 600,
         wallclockTimeUpdateInterval: 50,
         lowLatencyEnabled: false,
         keepProtectionMediaKeys: false,
         useManifestDateHeaderTimeSource: true,
         useSuggestedPresentationDelay: true,
         useAppendWindow: true,
         manifestUpdateRetryInterval: 100,
         liveCatchup: {
             minDrift: 0.02,
             maxDrift: 0,
             playbackRate: 0.5,
             latencyThreshold: NaN,
             playbackBufferMin: NaN,
             enabled: false,
             mode: Constants.LIVE_CATCHUP_MODE_DEFAULT
          },
         lastBitrateCachingInfo: { enabled: true, ttl: 360000 },
         lastMediaSettingsCachingInfo: { enabled: true, ttl: 360000 },
         cacheLoadThresholds: { video: 50, audio: 5 },
         fragmentRequestTimeout: 0,
         retryIntervals: {
             MPD: 500,
             XLinkExpansion: 500,
             InitializationSegment: 1000,
             IndexSegment: 1000,
             MediaSegment: 1000,
             BitstreamSwitchingSegment: 1000,
             other: 1000,
             lowLatencyReductionFactor: 10
         },
         retryAttempts: {
             MPD: 3,
             XLinkExpansion: 1,
             InitializationSegment: 3,
             IndexSegment: 3,
             MediaSegment: 3,
             BitstreamSwitchingSegment: 3,
             other: 3,
             lowLatencyMultiplyFactor: 5
         },
         abr: {
             movingAverageMethod: Constants.MOVING_AVERAGE_SLIDING_WINDOW,
             ABRStrategy: Constants.ABR_STRATEGY_DYNAMIC,
             bandwidthSafetyFactor: 0.9,
             useDefaultABRRules: true,
             useBufferOccupancyABR: false,
             useDeadTimeLatency: true,
             limitBitrateByPortal: false,
             usePixelRatioInLimitBitrateByPortal: false,
             maxBitrate: { audio: -1, video: -1 },
             minBitrate: { audio: -1, video: -1 },
             maxRepresentationRatio: { audio: 1, video: 1 },
             initialBitrate: { audio: -1, video: -1 },
             initialRepresentationRatio: { audio: -1, video: -1 },
             autoSwitchBitrate: { audio: true, video: true },
             fetchThroughputCalculationMode: Constants.ABR_FETCH_THROUGHPUT_CALCULATION_DOWNLOADED_DATA
         },
         cmcd: {
             enabled: false,
             sid: null,
             cid: null,
             did: null
         }
     }
}

RequestTypeSettings

Type:
  • Object
Properties:
Name Type Argument Description
MPD number <optional>

Manifest type of requests
XLinkExpansion number <optional>

XLink expansion type of requests
InitializationSegment number <optional>

Request to retrieve an initialization segment
IndexSegment number <optional>

Request to retrieve an index segment (SegmentBase)
MediaSegment number <optional>

Request to retrieve a media segment (video/audio/image/text chunk)
BitstreamSwitchingSegment number <optional>

Bitrate stream switching type of request
other number <optional>

Other type of request
Source:

StreamingSettings

Type:
  • Object
Properties:
Name Type Argument Default Description
metricsMaxListDepth number <optional>
 1000

Maximum list depth of metrics.
abandonLoadTimeout number <optional>
 10000

A timeout value in seconds, which during the ABRController will block switch-up events. This will only take effect after an abandoned fragment event occurs.
liveDelayFragmentCount number <optional>
 NaN

Changing this value will lower or increase live stream latency. The detected segment duration will be multiplied by this value to define a time in seconds to delay a live stream from the live edge. Lowering this value will lower latency but may decrease the player's ability to build a stable buffer.
liveDelay number <optional>

Equivalent in seconds of setLiveDelayFragmentCount

Lowering this value will lower latency but may decrease the player's ability to build a stable buffer.

This value should be less than the manifest duration by a couple of segment durations to avoid playback issues

If set, this parameter will take precedence over setLiveDelayFragmentCount and manifest info
scheduleWhilePaused boolean <optional>
 true

Set to true if you would like dash.js to keep downloading fragments in the background when the video element is paused.
fastSwitchEnabled boolean <optional>
 false

When enabled, after an ABR up-switch in quality, instead of requesting and appending the next fragment at the end of the current buffer range it is requested and appended closer to the current time When enabled, The maximum time to render a higher quality is current time + (1.5 * fragment duration).

Note, When ABR down-switch is detected, we appended the lower quality at the end of the buffer range to preserve the higher quality media for as long as possible.

If enabled, it should be noted there are a few cases when the client will not replace inside buffer range but rather just append at the end. 1. When the buffer level is less than one fragment duration 2. The client is in an Abandonment State due to recent fragment abandonment event.

Known issues:

  1. In IE11 with auto switching off, if a user switches to a quality they can not download in time the fragment may be appended in the same range as the playhead or even in the past, in IE11 it may cause a stutter or stall in playback.
flushBufferAtTrackSwitch boolean <optional>
 false

When enabled, after a track switch and in case buffer is being replaced (see MEdiaPlayer.setTrackSwitchModeFor(Constants.TRACK_SWITCH_MODE_ALWAYS_REPLACE)), the video element is flushed (seek at current playback time) once a segment of the new track is appended in buffer in order to force video decoder to play new track. This can be required on some devices like GoogleCast devices to make track switching functional. Otherwise track switching will be effective only once after previous buffered track is fully consumed.
calcSegmentAvailabilityRangeFromTimeline boolean <optional>
 false

Enable calculation of the DVR window for SegmentTimeline manifests based on the entries in

reuseExistingSourceBuffers boolean <optional>
 true

Enable reuse of existing MediaSource Sourcebuffers during period transition
bufferPruningInterval number <optional>
 10

The interval of pruning buffer in sconds.
bufferToKeep number <optional>
 20

This value influences the buffer pruning logic. Allows you to modify the buffer that is kept in source buffer in seconds. 0|-----------bufferToPrune-----------|-----bufferToKeep-----|currentTime|
jumpGaps boolean <optional>
 true

Sets whether player should jump small gaps (discontinuities) in the buffer.
jumpLargeGaps boolean <optional>
 true

Sets whether player should jump large gaps (discontinuities) in the buffer.
smallGapLimit number <optional>
 1.8

Time in seconds for a gap to be considered small.
stableBufferTime number <optional>
 12

The time that the internal buffer target will be set to post startup/seeks (NOT top quality).

When the time is set higher than the default you will have to wait longer to see automatic bitrate switches but will have a larger buffer which will increase stability.
bufferTimeAtTopQuality number <optional>
 30

The time that the internal buffer target will be set to once playing the top quality. If there are multiple bitrates in your adaptation, and the media is playing at the highest bitrate, then we try to build a larger buffer at the top quality to increase stability and to maintain media quality.
bufferTimeAtTopQualityLongForm number <optional>
 60

The time that the internal buffer target will be set to once playing the top quality for long form content.
longFormContentDurationThreshold number <optional>
 600

The threshold which defines if the media is considered long form content. This will directly affect the buffer targets when playing back at the top quality.
wallclockTimeUpdateInterval number <optional>
 50

How frequently the wallclockTimeUpdated internal event is triggered (in milliseconds).
lowLatencyEnabled boolean <optional>
 false

Enable or disable low latency mode
keepProtectionMediaKeys boolean <optional>
 false

Set the value for the ProtectionController and MediaKeys life cycle. If true, the ProtectionController and then created MediaKeys and MediaKeySessions will be preserved during the MediaPlayer lifetime.
useManifestDateHeaderTimeSource boolean <optional>
 true

Allows you to enable the use of the Date Header, if exposed with CORS, as a timing source for live edge detection. The use of the date header will happen only after the other timing source that take precedence fail or are omitted as described.
useSuggestedPresentationDelay boolean <optional>
 true

Set to true if you would like to override the default live delay and honor the SuggestedPresentationDelay attribute in by the manifest.
useAppendWindow boolean <optional>
 true

Specifies if the appendWindow attributes of the MSE SourceBuffers should be set according to content duration from manifest.
manifestUpdateRetryInterval number <optional>
 100

For live streams, set the interval-frequency in milliseconds at which dash.js will check if the current manifest is still processed before downloading the next manifest once the minimumUpdatePeriod time has
stallThreshold number <optional>
 0.5

Stall threshold used in BufferController.js to determine whether a track should still be changed and which buffer range to prune.
lastBitrateCachingInfo module:Settings~CachingInfoSettings <optional>
 {enabled: true, ttl: 360000}

Set to false if you would like to disable the last known bit rate from being stored during playback and used to set the initial bit rate for subsequent playback within the expiration window.

The default expiration is one hour, defined in milliseconds. If expired, the default initial bit rate (closest to 1000 kbps) will be used for that session and a new bit rate will be stored during that session.
lastMediaSettingsCachingInfo module:Settings~CachingInfoSettings <optional>
 {enabled: true, ttl: 360000}

Set to false if you would like to disable the last known lang for audio (or camera angle for video) from being stored during playback and used to set the initial settings for subsequent playback within the expiration window.

The default expiration is one hour, defined in milliseconds. If expired, the default settings will be used for that session and a new settings will be stored during that session.
cacheLoadThresholds module:Settings~AudioVideoSettings <optional>
 {video: 50, audio: 5}

For a given media type, the threshold which defines if the response to a fragment request is coming from browser cache or not.
fragmentRequestTimeout module:Settings~RequestTypeSettings <optional>

Time in milliseconds before timing out on loading a media fragment. Fragments that timeout are retried as if they failed.
retryIntervals module:Settings~RequestTypeSettings <optional>

Time in milliseconds of which to reload a failed file load attempt. For low latency mode these values are divided by lowLatencyReductionFactor.
retryAttempts module:Settings~RequestTypeSettings <optional>

Total number of retry attempts that will occur on a file load before it fails. For low latency mode these values are multiplied by lowLatencyMultiplyFactor.
abr module:Settings~AbrSettings

Adaptive Bitrate algorithm related settings.
cmcd module:Settings~CmcdSettings

Settings related to Common Media Client Data reporting.
liveCatchup module:Settings~LiveCatchupSettings

Settings related to live catchup.
Source: