Offline Work Mode

„Offline work mode! How we enabled offline work possibilities in our browser-based video editor….”

Have you ever been on a tough timeline with the need to finish your editing project, but still need to be somewhere? Maybe on a train or an aircraft where no suitable internet connection was available? Have you ever thought about using a webpage like our browser-based video editor VidiEditor while not being connected to the internet? Well, we believe it’s possible and can tackle this problem.

The base: Web Render Engine

In the previous blog post Bringing Browser-Based Video Editing to the Next Level we explained how we created the foundation for a fast and efficient video playback usable for editing including complex timeline sequences with effects, audio mixdowns and other options. With this technology step done, the question was: “What else is possible with this?”.

VidiEditor, being a browser-based application, running in a centralized Media Asset Management System, by design is already suitable for remote work. An offline work mode is a great extension of those possibilities to decouple from the needs for a stable internet connection. Combining this thought with the Web Render Engine possibilities the offline work mode concept was realized in 2024.

The Architecture Change

Coming from the status quo where a server connection is mandatory, Figure 1 can be used to understand basic dependencies of the software components used (see also: Architecture ).

Based on this it gets clear that different Software components are used server side to operate VidiEditor. Those are basically:

VidiStream API’s for Source and Timeline Preview
VidiCoder and Animation Render service for final HiRes conforming
VidiCore as Project, Media and Metadata repository

Going into the direction of disconnecting from the backend from here some possibilities needed to be cut off and user flows needed to change. It can be summed up with:

Media needed to be download by the user before going Offline, preview can then be done based on downloaded streams and Web Render Engine technology
Search of media needed to be limit to offline media only in offline mode.
Persistence of projects, metadata and autosave needed to work against a client-side data store
HiRes Publish must be disabled as the needed Transcoder is not available client side

Those are limitations on one hand, but on the other hand it is possible to use the source player for preview as well as the timeline doing the typical tasks such as multi track editing, audio and video effects as well as keyframes or voice over recordings. In result most of the editing work can be done offline already.

But how does the architecture of Figure 1 change then. Well, it simply looks as illustrated in Figure 2 where basically all media used for preview is load from cache including not only preview streaming but also trickplay functionalities such as trimming, seeking and scrubbing. Also, the work done by the user somehow must be remembered so the latest state of the project is persisted. Last but not least it is essential to also cache the VidiEditor frontend itself being able to load the webpage while being offline.

The User side of things

The dependencies and the complexity on the technical side is a valid point here and more aspects like authentication or configuration updates can come to account additionally. But what does the offline mode mean for the user? The VidiEditor GUI basically got extended by the possibilities of:

Downloading media from central system storage
Indicator and filtering of download media
Switch to enter/leave offline mode
Disabling GUI elements such as Animated Graphics and Publish

The UX here stay rather simple with buttons and an indicator on the media used as shown in Figure 3.

A user can simply use the VidiEditor online as before, an offline toggle mode would allow to switch to offline if needed due to no or very poor network connectivity. So, its the users choice to use the feature and to prepare the media needed.

But one point is not answered yet. The offline mode opens the potential of working on the same project offline and online with different users at the same time which easily creates conflicts when trying to merge it to one state again. Therefore, a hard decision must be made by the user when switching back online. VidiEditor will ask the user if the offline copy or the online version of the project should be used from that point on. After selecting the wanted choice VidiEditor will mange that data accordingly.

The Future of it

It was presented that an offline work mode in a modern browser-based editor is possible utilizing the possibilities Vidispine's Web Render Engine offers. Some limitations were mentioned, but can those be overcome?

The clear answer: It depends. For example, a publish without the centrally used transcoder would be implementable when limiting quality to a standard web video format such as MP4 / H.264 which would be also used as preview then. This could be sufficient when using FullHD media depending on the needed use case but not for a traditional linear TV production probably. Another idea could be running a transcoder locally, but this contradicts the idea of using low performance office PCs for video editing quiet a bit.

Also, usage of animated graphics and markers was out of scope here and would require additional thoughts and implementations but possibilities exist to improve here too.

Furthermore, it should be evaluated how big the user need is to work offline in VidiEditor even more. Watch out for more news around this or other feature based on Web Render Engine and other Vidispine technologies on upcoming blog posts.

Offline Work Mode