@api.video/media-stream-composer
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0.2.3 • Public • Published

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api.video media composer

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api.video is the video infrastructure for product builders. Lightning fast video APIs for integrating, scaling, and managing on-demand & low latency live streaming features in your app.

Table of contents

Project description

This library lets you easily record & upload videos to api.video from a composition of several media streams. The position and size of each stream can be set in a flexible and easy way.

This allows for example, with only a few lines of code, to create a video composed of: "entire screen capture in the left half, window #1 capture in the right half, and the webcam in a circular shape in the bottom left of the video".

The code of a small Next.js application demonstrating the different features offered by the library is available in the examples/record.a.video folder. If you want to try it live, go here: https://record.a.video.

Getting started

Installation

Installation method #1: requirejs

If you use requirejs you can add the library as a dependency to your project with

$ npm install --save @api.video/media-stream-composer

You can then use the library in your script:

var { MediaStreamComposer } = require('@api.video/media-stream-composer');

var composer = new MediaStreamComposer({
    resolution: {
        width: 1280,
        height: 720
    }
}); 

Installation method #2: ES6 modules

You can add the library as a dependency to your project with

$ npm install --save @api.video/media-stream-composer

You can then use the library in your script:

import { MediaStreamComposer } from '@api.video/media-stream-composer'

const composer = new MediaStreamComposer({
    resolution: {
        width: 1280,
        height: 720
    }
});

Simple include in a javascript project

Include the library in your HTML file like so:

<head>
    ...
    <script src="https://unpkg.com/@api.video/media-stream-composer" defer></script>
</head>

Then you can instantiate the composer using new MediaStreamComposer():

...
<script type="text/javascript"> 
    const composer = new MediaStreamComposer({
        resolution: {
            width: 1280,
            height: 720
        }
    });
</script>

Documentation

Instantiation

Options

The media stream composer is instantiated using an options object. At the moment, it contains only one option: resolution. If provided, this option must contain a width and a height property. This resolution will be used to create the canvas element that will be used to draw the streams. It will also be used to set the resolution of the video when it is uploaded.

If the resolution option is not provided, the canvas will be created with this resolution: 1280x720.

Methods

addStream(mediaStream: MediaStream | HTMLImageElement, options: StreamOptions): string

The addStream() method adds a stream to the composition. A stream can be either a MediaStream (for example, the webcam, the screen, or a window capture) or an HTMLImageElement (for example, a logo).

It takes a MediaStream | HTMLImageElement and an StreamOptions parameter.

Note regarding images origin

When you load an image onto the composition, the origin of the image must be the same as the origin of the webpage in order for the image to be displayed correctly. This means that the image must be served from the same domain, or the server hosting the image must include the appropriate CORS (Cross-Origin Resource Sharing) headers to allow the image to be displayed on the canvas from a different origin. More details here: https://developer.mozilla.org/en-US/docs/Web/HTML/CORS_enabled_image .

Options

Option name Type Default value Description
name string undefined An optional name for the stream
position contain | cover | fixed contain contain: the stream will be contained in the canvas, cover: the stream will be covered by the canvas, fixed: the stream will be fixed in the canvas
x number undefined x position of the stream (in pixels, only if position = fixed)
y number undefined y position of the stream (in pixels, only if position = fixed)
width number undefined width of the stream (in pixels, only if position = fixed)
height number undefined height of the stream (in pixels, only if position = fixed)
draggable boolean false Whether the stream can be moved by dragging it (see bellow mouse interactions)
resizable boolean false Whether the stream can be resized by dragging its borders (see bellow mouse interactions)
mask none | circle none Whether the stream should be masked with a circle or not
mute boolean false Whether the stream should be muted or not
hidden boolean false Whether the stream should be hidden or not
opacity number 100 Opacity of the stream (from 0 to 100)
onClick (streamId: string, event: { x: number; y: number; }) => void undefined A callback function that will be called when the stream is clicked

Example (screen capture)

navigator.mediaDevices.getDisplayMedia({ video: true, audio: false }).then((stream) => {
    const streamId = composer.addStream(stream, {
        position: "fixed",
        x: 100,
        y: 100,
        width: 300,
        draggable: true,
        resizable: true,
        mask: "circle",
        opacity: 90,
        onClick: (streamId, event) => {
            console.log(streamId, event.x, event.y);
        }
    });

    // ...
});

Example (image)

const image = new Image();
image.crossOrigin = 'anonymous';
image.src = "./my-logo.jpg"; 

const streamId = composer.addStream(image, {
    position: "fixed",
    x: 100,
    y: 100,
    width: 300,
    draggable: true,
    resizable: true,
    mask: "none"
});

updateStream(streamId: string, options: StreamOptions): void

Update the options of an existing stream. It takes the id of the stream (the one returned by the addStream() method) and an StreamOptions parameter (same as for the addStream() method).

Example

composer.updateStream(streamId, {
    hidden: true,
});

removeStream(id: string): void

Remove a stream from the composition. The id is the same as the one returned by the addStream() method.

Example

composer.removeStream(streamId);

getStreams(): StreamDetails[]

Returns an array of objects containing the details of all the streams in the composition.

Example

const streams = composer.getStreams();
/*
    streams: [{
        "id": "0",
        "options": {
            "position": "fixed",
            "height": 192,
            "x": 0,
            "y": 0,
            "resizable": true,
            "draggable": true,
            "mask": "circle",
            "name": "#0 webcam"
        },
        "displaySettings": {
            "radius": 96,
            "displayResolution": {
                "width": 192,
                "height": 192
            },
            "position": {
                "x": 0,
                "y": 0
            },
            "streamResolution": {
                "width": 640,
                "height": 480
            },
            "index": 1
        },
        "stream": {}
    }]
*/

getStream(id: string): StreamDetails

Get the details of a stream. It takes the id of the stream. The id is the same as the one returned by the addStream() method.

Example

const stream = composer.getStream(streamId);

addAudioSource(mediaStream: MediaStream): string

The addAudioSource() method adds a stream as an audio source to the composition. It takes a MediaStream parameter. The display won't be impacted by the stream. Only the audio will be mixed. |

Example

navigator.mediaDevices.getDisplayMedia({ audio: { deviceId: selectedAudioSource }).then((stream) => {
    const audioSourceId = composer.addAudioSource(stream);
});

removeAudioSource(id: string): void

Remove an audio source from the composition. The id is the same as the one returned by the addAudioSource() method.

Example

composer.removeAudioSource(audioSourceId);

getAudioSources(): AudioSourceDetails[]

Returns an array of objects containing the details of all the streams in the composition.

Example

const audioSources = composer.getAudioSources();
/*
    audioSources: [{
        "id": "audio_0",
        "stream": {}
    }]
*/

getAudioSource(audioSourceId: string): AudioSourceDetails

Get the details of an audio source. It takes the id of the audio source. The id is the same as the one returned by the addAudioSource() method.

Example

const stream = composer.getAudioSource(audioSourceId);

moveUp(streamId: string): void

Move a stream up in the composition (ie. move it above the stream that was above it). The id is the same as the one returned by the addStream() method.

Example

composer.moveUp(streamId);

moveDown(streamId: string): void

Move a stream down in the composition (ie. move it below the stream that was below it). The id is the same as the one returned by the addStream() method.

Example

composer.moveDown(streamId);

startRecording(options: RecordingOptions): void

Start recording the composition & upload it to your api.video account. It takes an RecordingOptions parameter.

Options

Options to provide depend on the way you want to authenticate to the api.video API: either using a delegated upload token (recommanded), or using a usual access token.

Using a delegated upload token (recommended):

Using delegated upload tokens for authentication is best options when uploading from the client side. To know more about delegated upload token, read the dedicated article on api.video's blog: Delegated Uploads.

Option name Mandatory Type Description
uploadToken yes string your upload token
videoId no string id of an existing video
common options (see bellow)
Using an access token (discouraged):

Warning: be aware that exposing your access token client-side can lead to huge security issues. Use this method only if you know what you're doing :).

Option name Mandatory Type Description
accessToken yes string your access token
videoId yes string id of an existing video
common options (see bellow)
Common options
Option name Mandatory Type Description
videoName no string the name of your recorded video (overrides the default "file" name)
apiHost no string api.video host (default: ws.api.video)
retries no number number of retries when an API call fails (default: 5)

Example

composer.startRecording({
    uploadToken: "YOUR_DELEGATED_TOKEN",
    retries: 10,
});

stopRecording(): Promise<VideoUploadResponse>

The stopRecording() method stops the recording of the composition. It takes no parameter. It returns a Promise that resolves with the newly created video.

Example

composer.stopRecording().then(e => console.log(`player url: ${e.assets.player}`));

getCanvas(): HTMLCanvasElement | undefined

Returns the canvas used to draw the composition. It takes no parameter.

Example

const canvas = composer.getCanvas();

appendCanvasTo(containerQuerySelector: string): void

Append the canvas used to draw the composition to an HTML container. It takes a string containing the query selector of the container.

That's useful if you want to display the composition in a web page.

Additionally, it's mandatory is you want to use mouse-based features like dragging, resizing and drawing.

Example

<div id="container"></div>
<script>
    // ....
    composer.appendCanvasTo("#container");
</script>

setMouseTool(tool: "draw" | "move-resize"): void

Define the kind of action that will be performed when the user interact with the canvas using the mouse. It takes a string containing the name of the tool.

Tools:

  • move-resize: move and resize a stream
  • draw: draw on a stream (drawing settings can be defined using the setDrawingSettings() method)

Example

composer.setMouseTool("draw");

setDrawingSettings(settings: Partial<DrawingSettings>): void

Set the drawing settings for the draw tool. It takes a DrawingSettings parameter that contains the following attributes:

  • color: the color of the drawing
  • lineWidth: the width of the drawing
  • autoEraseDelay: the delay before the drawing is erased (in seconds - 0 means no delay)

Example

composer.setDrawingSettings({
    color: "#FF0000",
    lineWidth: 5,
    autoEraseDelay: 3,
});

clearDrawing(): void

Clear all the drawings on the canvas. It takes no parameter.

Example

composer.clearDrawing();

addEventListener(event: string, listener: Function)

Define an event listener for the media recorder. The following events are available:

  • "error": when an error occurs
  • "recordingStopped": when the recording is stopped

Example

    composer.addEventListener("error", (event) => {
       console.log(event.data);
    });

destroy()

Destroys all streams and releases all resources in use.

Full examples

"Loom-like"

This samples shows how to use the composer to create a screencast with a webcam stream in the corner.

It has the following features:

  • the screencast stream is added in the background and it's size is automatically adjusted to the size of the composition (contain dimensions)
  • the webcam stream is added in front of the screencast stream, in the bottom-left corner, and it's displayed in a circle - the stream is draggable and resizable
  • switching between the "drawing" and "moving/resizing" tools is possible using radio buttons
<html>
    <head>
        <script src="https://unpkg.com/@api.video/media-stream-composer"></script>
        <style>
            body {
                font-family: 'Lucida Sans', 'Lucida Sans Regular', 'Lucida Grande', 'Lucida Sans Unicode', Geneva, Verdana, sans-serif;
            }
            #container {
                display: flex;
                flex-direction: column;
                align-items: center;
            }

            #video {
                border: 1px solid gray;
            }

            #container div {
                margin: 10px 0;
            }
        </style>
    </head>

    <body>
        <div id="container">
            <div id="canvas-container"> </div>
            <div>
                <button id="start">start recording</button>
                <button id="stop" disabled>stop recording</button>
            </div>
            <div>
                <label for="tool-select">Tool:</label>
                <select id="tool-select">
                    <option value="draw">draw</option>
                    <option selected value="move-resize">move/resize</option>
                </select>
            </div>
            <div>
                <p>Video link: <span id="video-link"><i>will be displayed when the recording is finished</i></span></p>
            </div>
        </div>

        <script>
            const canvasContainer = document.getElementById('canvas-container');
            const toolSelect = document.getElementById("tool-select");
            const startButton = document.getElementById("start");
            const stopButton = document.getElementById("stop");
            const videoLink = document.getElementById("video-link");
            const width = 1366;
            const height = 768;

            canvasContainer.style.width = `${width}px`;
            canvasContainer.style.height = `${height}px`;



            (async () => {
                const screencast = await navigator.mediaDevices.getDisplayMedia();
                const webcam = await navigator.mediaDevices.getUserMedia({
                    audio: true,
                    video: true
                });

                // create the media stream composer instance
                const mediaStreamComposer = new MediaStreamComposer({
                    resolution: {
                        width,
                        height
                    }
                });

                // add the screencast stream
                mediaStreamComposer.addStream(screencast, {
                    position: "contain",
                    mute: true,
                });

                // add the webcam stream in the lower left corner, with a circle mask
                mediaStreamComposer.addStream(webcam, {
                    position: "fixed",
                    mute: false,
                    y: height - 200,
                    left: 0,
                    height: 200,
                    mask: "circle",
                    draggable: true,
                    resizable: true,
                });

                // display the canvas (preview purpose)
                mediaStreamComposer.appendCanvasTo("#canvas-container");

                // when the start button is clicked, start the recording
                startButton.onclick = () => {
                    mediaStreamComposer.startRecording({
                        uploadToken: "YOUR_UPLOAD_TOKEN",
                    });
                    startButton.disabled = true;
                    stopButton.disabled = false;
                }

                // when the stop button is clicked, stop the recording and display the video link
                stopButton.onclick = () => {
                    mediaStreamComposer.stopRecording().then(a => videoLink.innerHTML = a.assets.player);
                    stopButton.disabled = true;
                    startButton.disabled = false;
                }


                mediaStreamComposer.setDrawingSettings({
                    color: "#FF0000",
                    lineWidth: 5,
                    autoEraseDelay: 3,
                });

                toolSelect.onchange = (a) => mediaStreamComposer.setMouseTool(a.target.value);
            })();
        </script>
    </body>

</html>

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