Audio track side-loading

August 2024

What’s changing

MK.IO now supports side-loading of audio for assets.

Who is impacted

Anyone who is using MK.IO for VOD transcoding and willing to enrich their VOD assets with one or more audio files.

Why you would use this / Why it matters

When transcoding VOD content, the source asset may not have the required auddio tracks. Some audio tracks can come later in the process or even be generated using an AI pipeline on the side. In such cases, MK.IO offers a simple API solution to add an audio file to an existing asset, ensuring that your users have access to audio during playback.

MK.IO allows you to set the language and accessibility parameters for the audio track you are adding it.

Additional details

Side-loading of an audio track is done through a new transform type in MK.IO.

👉

If the manifest has been played back before inserting a subtitle track, there will be a delay of up to 60s before the manifest will contain the subtitles, due to cache settings.

For more details, refer to Track Insertion transform.

Getting started

Adding a new audio track to an existing asset is as simple as creating a new job using a track insertion transform: you specify the audio file to use as input and the destination asset to use as output.

This operation is only available using the API, sample track insertion transforms are provided in this article.

Availability & rollout plan

Audio track side-loading is available in all regions starting November 14th 2025.

Metering & Pricing

There is no additional charge associated to this feature.