Segment EMSG Parser

A small package for reading emsg boxes from a mp4 segment.

Usage

npm install @eyevinn/segment-emsg-parser

yarn add @eyevinn/segment-emsg-parser

import { extractEmsgArrayFromSegment } from "@Eyevinn/segment-emsg-parser";

const response = await fetch("segment.m4s");
const buffer = await response.arrayBuffer();

const emsgArray = extractEmsgArrayFromSegment(buffer);

Develop

Install Node, npm, and yarn v3. Clone the repo and run yarn to install dependencies.

yarn dev will start a dev server where you can test parsing of segments.

Git Ways of Working

The project uses feature branches, and a rebase merge strategy.

Make sure you have git pull set to rebase mode:

git config pull.rebase true

Optionally, you can add the --global flag to the above command.

To start working on a new feature: git checkout <feature branch name>.

As the project uses semantic-release to automatically generate release notes based on commits, it is important to follow some rules when committing.

This project uses conventional commits.

Read Using Git with Discipline.

Read How to Write a Commit Message.

A commit should:

• contain a single change set (smaller commits are better)
• pass tests, linting, and typescript checks
• not be broken

Along with enabling time saving automation, it enables extremely powerful debug workflows via git bisect, making bug hunting a matter of minutes instead of days. There are a number of articles out there on the magic of bisecting.

Basic structure of a commit message:

<type>[optional scope]: <title starting with verb in infinitive>

[optional body]

[optional footer]

For automated release notes to work well, try to describe what was added or changed, instead of describing what the code does. Example:

fix(seek): rewrite calculation in seek module // bad, the consumer does not know what issue this fixes

fix(seek): stop player from freezing after seek // good, the consumer understands what is now working again

Releasing

Releases are triggered via a github action that will automatically increment the version and write a changelog based on commits.

Manual releases can be made by running yarn release.

Support

Join our community on Slack where you can post any questions regarding any of our open source projects. Eyevinn's consulting business can also offer you:

• Further development of this component
• Customization and integration of this component into your platform
• Support and maintenance agreement

Contact [email protected] if you are interested.

About Eyevinn Technology

Eyevinn Technology is an independent consultant firm specialized in video and streaming. Independent in a way that we are not commercially tied to any platform or technology vendor. As our way to innovate and push the industry forward we develop proof-of-concepts and tools. The things we learn and the code we write we share with the industry in blogs and by open sourcing the code we have written.

Want to know more about Eyevinn and how it is to work here. Contact us at [email protected]!