Some uploaded videos have no audio — screen recordings, time-lapses, security camera clips. The default conversion pipeline expects an audio track and can fail or produce muted output. This article explains how the platform handles these and how to tune the behaviour.
Detection
The probe step uses FFmpeg's stream introspection to detect whether the file contains an audio track. Detection is reliable for all standard container formats.
Behaviour Options
- Auto-detect and mark silent (default): Conversion runs as normal; the resulting metadata marks the file as silent so player UIs can hide the volume control.
- Insert silent audio track: Adds a silent AAC track so the file plays through audio-aware pipelines that require one.
- Reject upload: Refuse silent videos at upload — useful when audio is genuinely required (e.g. an interview platform).
- Auto-mute and proceed: Old behaviour; deprecated.
Why Inserting Silent Tracks Matters
Some downstream systems (broadcast servers, video editors, captioning workflows) expect every video file to have an audio track even if empty. Inserting a silent track keeps those pipelines happy without changing the user's perception.
Worked Examples
- Screen recording library: Default behaviour — silent flag respected, player hides the volume control.
- Broadcast pipeline: Insert silent track so downstream broadcast schedulers don't crash on missing audio.
- Interview platform: Reject silent uploads — audio is the whole point.
- Security camera feed: Default — silent flag set; alerts use motion not audio.