Multi-track audio and subtitle support across all playback IDs

FastPix now offers a unified multi-track audio and subtitle workflow that applies to every playback ID associated with a media asset. Previously, track operations only worked against a single default playback configuration; tracks you added would not be reflected when the media was viewed through alternate playback IDs (for example, DRM-protected or public playback IDs on the same media). With this release the track lifecycle — create, update, and delete — is fully propagated across all playback IDs and surfaced consistently in the API, in webhook events, and in the underlying manifest.

You can attach audio tracks (dubs, alternate languages, descriptive audio) and subtitle tracks (closed captions, translations) at media creation time or anytime after upload using the track-upload endpoint. Each track carries an explicit languageName and languageCode so players can render proper language menus and accessibility hints without additional API lookups.

Key changes:

• Track endpoints: dedicated POST, PATCH, and DELETE endpoints let you add new tracks, update an existing track’s metadata, or remove a track from a media’s manifest after it has already been published.

If you were previously tracking tracks per playback ID, you can now manage them once at the media level and rely on FastPix to reconcile state across every playback configuration. No migration is required — existing media will see the new track endpoints become active automatically.