For auto-generated captions Mux Video now reports skipped track status and video.asset.track.skipped webhook for assets with no audio. Previously the reported status was errored and the webhook fired was video.asset.track.errored. This new skipped status better communicates the reason that a transcript and track could not be generated when audio is not available.
Webhook: https://www.mux.com/docs/webhook-reference#video.asset.track.skipped
Updated API spec: https://www.mux.com/api-spec.json
Auto-generated captions guide: https://www.mux.com/docs/guides/add-autogenerated-captions-and-use-transcripts