WHIP
An output type that allows streaming video and audio from the Smelter over WHIP.
import Smelter from "@swmansion/smelter-node";import { View } from "@swmansion/smelter";
async function run() { const smelter = new Smelter(); await smelter.init(); await smelter.registerOutput("example", <View />, { type: "rtp_stream", port: 8001, transportProtocol: "tcp_server", video: { encoder: { type: "ffmpeg_h264" }, resolution: { width: 1920, height: 1080 }, } }); // At this point you can connect to 8001 TCP port // and start receiving RTP traffic.}void run();RegisterWhipOutput
import { Outputs, RegisterWhipOutput } from "@swmansion/smelter"Parameters for an WHIP output stream from the Smelter.
Type definitions
type RegisterWhipOutput = { endpointUrl: string; bearerToken?: string; video?: Outputs.WhipVideoOptions; audio?: Outputs.WhipAudioOptions;};Properties
endpointUrl
The destination URL for sending media streams using the WHIP.
- Type:
string
bearerToken
Token used for authentication when connecting to the WHIP endpoint.
- Type:
string
video
Parameters of a video included in the WHIP stream.
audio
Parameters of an audio included in the WHIP stream.
Outputs.OutputWhipVideoOptions
import { Outputs } from "@swmansion/smelter"Parameters of a video source included in the WHIP stream.
Type definitions
type WhipVideoOptions = { resolution: { width: number; height: number; }; sendEosWhen?: Outputs.OutputEndCondition; encoder: Outputs.WhipVideoEncoderOptions;};Properties
resolution
Output resolution in pixels.
- Type:
{ width: number; height: number;}
sendEosWhen
Condition for termination of the output stream based on the input streams states. If output includes both audio and video streams, then EOS needs to be sent for every type.
encoder
Video encoder options.
Outputs.WhipVideoEncoderOptions
import { Outputs } from "@swmansion/smelter"Configuration for the video encoder, based on the selected codec.
Type definitions
type WhipVideoEncoderOptions = { type: "ffmpeg_h264"; preset: | "ultrafast" | "superfast" | "veryfast" | "faster" | "fast" | "medium" | "slow" | "slower" | "veryslow" | "placebo"; ffmpegOptions?: Map<string, string>; }Properties (type: “ffmpeg_h264”)
preset
Video output encoder preset. Visit FFmpeg docs to learn more.
- Type:
"ultrafast" | "superfast" | "veryfast" | "faster" | "fast" | "medium" | "slow" | "slower" | "veryslow" | "placebo" - Default value:
fast - Supported values:
ultrafastsuperfastveryfastfasterfastmediumslowslowerveryslowplacebo
ffmpegOptions
Raw FFmpeg encoder options. Visit FFmpeg docs to learn more.
- Type:
Map<string, string>
Outputs.WhipAudioOptions
import { Outputs } from "@swmansion/smelter"Parameters of an audio source included in the WHIP stream.
Type definitions
type WhipAudioOptions = { mixingStrategy?: "sum_clip" | "sum_scale"; sendEosWhen?: Outputs.OutputEndCondition; encoder: Outputs.WhipAudioEncoderOptions;}Properties
mixingStrategy
Specifies how audio should be mixed.
- Type:
"sum_clip" | "sum_scale" - Default value:
"sum_clip" - Supported values:
sum_clip- First, the input samples are summed. If the result exceeds the i16 PCM range, it is clipped.sum_scale- First, the input samples are summed. If the result exceeds the i16 PCM range, the summed samples are scaled down by a factor to fit within the range.
sendEosWhen
Condition for termination of the output stream based on the input streams states. If output includes both audio and video streams, then EOS needs to be sent for every type.
encoder
Audio encoder options.
Outputs.WhipAudioEncoderOptions
import { Outputs } from "@swmansion/smelter"Configuration for the audio encoder, based on the selected codec.
Type definitions
type WhipAudioEncoderOptions = { type: "opus"; channels: "mono" | "stereo"; preset?: "quality" | "voip" | "lowest_latency"; sampleRate?: number }Properties(type: “opus”)
channels
Channels configuration
- Type:
"mono" | "stereo" - Supported values:
mono- Mono audio (single channel).stereo- Stereo audio (two channels).
preset
Audio output encoder preset.
- Type:
"quality" | "voip" | "lowest_latency" - Default value:
voip - Supported values:
quality- Recommended for broadcast and high-fidelity applications requiring decoded audio to maintain maximum fidelity to the input signal.voip- Recommended for VoIP and videoconferencing applications, prioritizing listening quality and speech intelligibility.lowest_latency- Recommended only when achieving the lowest possible latency is the highest priority.
sampleRate
Sample rate for audio encoder.
- Type:
number - Supported values:
8000,16000,24000,48000.
Outputs.OutputEndCondition
import { Outputs } from "@swmansion/smelter"Defines when the output stream should end based on the state of the input streams. Only one of the nested fields can be set at a time.
By default, the input stream is considered finished/ended when:
- TCP connection was dropped/closed.
- RTCP Goodbye packet (BYE) was received.
- MP4 track has ended.
- Input was unregistered already (or never registered).
Type definitions
type OutputEndCondition = | { anyOf: string[]; } | { allOf: string[]; } | { anyInput: boolean; } | { allInputs: boolean; };Properties
anyOf
List of the input streams. The output stream will terminate if any stream in the list finishes.
- Type:
string[]
allOf
List of the input streams. The output stream will terminate when all streams in the list finish.
- Type:
string[]
anyInput
Terminate the output stream if any of the input streams end, including streams added after the output was registered. Notably, the output stream will not terminate if no inputs were ever connected.
- Type:
boolean
allInputs
Terminate the output stream only when all input streams have finished. Notably, the output stream will terminate if no inputs were ever connected.
- Type:
boolean