Publishing Parameters

Customizing the Publishing URLs

Broadcast URL Parameters allow you to customize the behavior of an individual source feed by modifying the URL used of specific sources when establishing a connection.

Broadcast Protocols

There are some variations depending on which protocol is being used to broadcast.

  • WebRTC: The query parameter string is appended at the end of a WHIP URL https endpoint.
  • RTMP: The query parameter string is appended to the end of a RTMP URL rtmp or rtmps endpoint. Depending on the encoder, this may be appended as a single URL or a two-part server and path.
  • SRT: The query parameter string requires special handling to encode it within the SRT stream id.

How-to Add Publishing Parameters to the URL

Parameters allow modifying broadcasting preferences to customize the streaming experience. This is particularly helpful when using Multi-Source that share a common publishing token configuration but may be using a feature that requires modification to only specific input streams.

To use these parameters, add them to the end of the protocol URI as a query string component.

  • All broadcast parameters are added after the ?token={token}
  • Parameters are delimited using an ampersand (&)

For example, to distinguish different sources you can add a sourceId and priority parameter to the URL. The result might look like:

?token={token}&sourceId=1&priority=1

Any parameters that are boolean type can be used without a value. For example, the audioOnly and noRecord parameters:

?token={token}&audioOnly&noRecord

Available Parameters

The Dolby.io Streaming APIs platform provides the following parameters:

Parameter nameTypeDescription
audioOnlyBooleanIndicates whether the platform should broadcast only audio.
intraOnlyForwardingBooleanIndicates whether the platform should forward only intra frames while transmitting video.
noAudioBooleanInstructs the server to ignore any audio tracks from this source. This is often used with Multi-Bitrate (MBR) contribution streams to only stream the audio of the main feed.
noRecordBooleanWhen given will not record the given ingest source feed. This overrides the publishing token to avoid recording multiple sources that might only be streaming as a backup or for MBR.
priorityNumberA priority for redundant streams indicates the order in which backup streams should be broadcasted in the case of any problems with the primary stream.
recordBooleanIndicates whether the platform should record a stream.
simulcastIdStringAn identifier that assigns feeds produced by a single camera as Simulcast layers. All feeds that have the same simulcastId are published together as different quality layers. You can identify each layer using a different sourceId.
sourceIdStringA unique identifier for a specific feed. Two feeds can have the same sourceId only when they are the same and used as backup feeds in Redundant Ingest .
streamNameStringA name for the stream of your broadcast. This must match the streamName(s) allowed by your publishing token.
tStringA publish token in the base64url format that is supported only when using SRT or RTMP. We recommend using this parameter to reduce the length of the query parameter string for encoders with low limits. It is not possible to use the t and token parameters at the same time.
tokenStringA publish token in the hexadecimal format that is supported only when using SRT or RTMP. It is not possible to use the t and token parameters at the same time.
videoOnlyBooleanIndicates whether the platform should broadcast only video even if the contribution stream contains an audio track. This is required when you are doing Multi-Bitrate Publishing on layers that do not contain an audio stream or contain a silent audio stream.
videoTargetBitrateNumberThe target bitrate of the streamed video content, in kbps. The parameter helps the service determine what layer to send to viewers while using multi-bitrate RTMP or SRT to deliver simulcast, or multiple-quality viewer experience. This parameter is supported only when using SRT or RTMP.