set_background_music
Set or replace the video’s background music track, from Tella’s curated music or from your own audio. For a curated track, calllist_library with scope: "default" and type: "music" and pass the item’s presetId — there is nothing to upload. For your own audio, call create_source first (kind: "audio" with the track’s duration), PUT the audio bytes to the returned uploadUrl, then pass the sourceId here.
To change only the volume or name of the track already on the video, pass neither presetId nor sourceId. The current track stays, and any field you omit keeps its current value. If the video has no background music yet, the call fails and asks for a source.
string
required
Video ID
string
Pass this or
sourceId to set a new track. Preset ID of a curated Tella music track, from a default item of type music in list_librarystring
Pass this or
presetId to set a new track. Audio source ID from create_source (kind: "audio")number
Volume from 0 to 1. Defaults to 0.2 for a new track; without
presetId or sourceId, keeps the current track’s volumestring
Display name for the track — defaults to the preset’s name when
presetId is given; without presetId or sourceId, keeps the current track’s nameremove_background_music
Remove the video’s background music track.string
required
Video ID
get_music_beats
Get the tempo, every beat and the first beat of every bar (the downbeats) of the video’s background music, or of any audio or video source, to cut, place overlays or start animations on the beat. WithvideoId, times are ms on the video’s playback timeline, the same times as get_timeline. The track starts at 0 and restarts every trackDurationMs until the video ends, so its beats repeat with it; it fades in over the first 2 seconds and out over the last 2. With sourceId, times are ms of source time.
confidence (0 to 1) says how clear the pulse is. Steady produced music is usually above 0.4; below about 0.1 the track is beatless ambient music and the beats are only a guess. Downbeats are least certain: in about one track in eight they land on the third beat of the bar instead of the first.
Each track is analyzed once and cached. The first call for a new track can take a few seconds, or fail as unavailable while the analysis finishes; call again.
string
Video whose background music to analyze. Pass this or
sourceIdstring
Audio or video source to analyze, in source time. Pass this or
videoIdbpm, beatsPerBar (4, or 3), confidence, trackDurationMs, durationMs (the video’s or source’s length), beatsMs and downbeatsMs.