MP4

Node.js Browser (Client) Browser (WASM)

An input type that allows Smelter to read static MP4 files.

Note

MP4 files can contain video and audio tracks encoded with various codecs. This input type supports MP4 video tracks encoded with h264 and audio tracks encoded with AAC.

If the file contains multiple audio or video tracks, only the first audio track and the first video track will be processed; all additional tracks will be ignored.

Caution

Browser (WASM) runtime (via package @swmansion/smelter-web-wasm) currently does not support audio from mp4 files.

Usage

mp4InputExample.tsx

import Smelter from "@swmansion/smelter-node";

async function run() {
  const smelter = new Smelter();
  await smelter.init();
  await smelter.registerInput("example", {
      type: "mp4",
      serverPath: "./input.mp4"
  });
}
void run();

Reference

Type definitions

type RegisterMp4Input = {
  type: "mp4";
  url?: string;
  serverPath?: string;
  loop?: bool;
  required?: bool;
  offsetMs?: number;
  decoderMap?: DecoderMap;
}

Parameters for registering an MP4 file as an input.

Note

Exactly one of url or serverPath has to be defined.

Properties

url

URL of the MP4 file.

• Type: string
• Option availability: Node.js , Browser (WASM)

---

serverPath

Path to the MP4 file, specifying its location on the server where the Smelter instance is deployed.

• Type: string
• Option availability: Node.js

---

loop

Specifies whether the input should be played in a loop.

• Type: boolean
• Default value: false
• Option availability: Node.js

---

required

Determines if the input stream is essential for output frame production. If set to true and the stream is delayed, Smelter will postpone output frames until the stream is received.

• Type: boolean
• Default value: false
• Option availability: Node.js

---

offsetMs

Offset in milliseconds relative to the pipeline start (start request). If unspecified, the stream synchronizes based on the delivery time of the initial frames.

• Type: number
• Option availability: Node.js

---

decoderMap

Assigns which decoder should be used for media encoded with a specific codec.

• Type: DecoderMap

DecoderMap

Maps codecs to the provided decoders.

Type definitions

type DecoderMap = {
  h264?: 'ffmpeg_h264' | 'vulkan_h264';
};

Properties

h264

H264 decoder configuration.

• Type: 'ffmpeg_h264' | 'vulkan_h264'
• Default value: If available vulkan_h264 will be used, otherwise ffmpeg_h264
• Supported values:
  • "ffmpeg_h264" - Software H264 decoder based on FFmpeg.
  • "vulkan_h264" (Required feature: vk-video ) - Hardware decoder. Requires GPU that supports Vulkan Video decoding.