Building FrameTrellis: My Journey Toward an Open-Source C++ Video Editor

I'm working toward the first stable v1.0.0 release of FrameTrellis, an open-source, local-first desktop video editor built with C++20, Qt 6/QML, MLT and FFmpeg.

This project combines my interest in native application development, multimedia workflows and building practical software that people can explore, test and contribute to.

The first stable release is still ahead, and I want to share the development journey rather than wait until everything is finished.

Why FrameTrellis?

Video editing applications bring together several challenging areas of software engineering: media handling, timeline interaction, playback, editing operations, project persistence and export.

FrameTrellis aims to bring these workflows together in a desktop application with a local-first approach.

It does not require an account and does not use cloud processing, telemetry or advertising. The goal is to keep the editing experience focused on the user's computer and local projects.

The technology behind the project

FrameTrellis uses several technologies with distinct responsibilities:

• C++20: Native application development.
• Qt 6/QML: Desktop interface and interactive application components.
• MLT: Multimedia editing and processing workflows.
• FFmpeg: Media handling and video export support.

Working with these technologies also means paying attention to dependencies, build configurations, testing and the differences between supported platforms.

What has been implemented?

The current development version includes a foundation for:

• Creating, opening and saving projects.
• Importing video, audio and still images.
• Multi-track timeline editing.
• Moving, trimming, splitting and deleting clips.
• Preview playback and frame navigation.
• Audio waveforms and basic picture adjustments.
• Dissolve transitions and audio crossfades.
• Undo/redo, autosave and crash recovery.
• Exporting MP4 video with H.264 and AAC.

The project documentation describes these implemented workflows and their automated tests. However, this does not mean every professional editing feature is available or that every platform has a stable packaged release.

What comes next?

There is still work ahead before v1.0.0 can be considered a stable release.

The roadmap includes improvements such as titles, subtitles, keyframes, proxy media, additional export formats and packaged releases. Testing, documentation and platform verification will remain important parts of the process.

I intend to share meaningful progress as features are implemented, tested and improved, including the engineering challenges that arise along the way.

Explore the project

FrameTrellis is open source under the GPL-3.0-or-later license.

Explore the source code, review the documentation and follow the development here:

GitHub: https://github.com/sanskarIN/frametrellis

Feedback, bug reports, testing and documentation contributions are welcome.

This is the beginning of the journey toward FrameTrellis v1.0.0. I'll share more as the project progresses.

What do you think an open-source video editor should prioritize before its first stable release: editing usability, export reliability or project safety?