language-swap

/pika:language-swap

Tools below are Pika MCP tools, named bare — call each under whatever prefix your session exposes for the Pika MCP.

Translate and dub a video into another language while preserving the original speaker's voice. Pipeline: dub (one worker call) → lipsync (default ON) → burn target-language captions or bilingual captions.

The dubbing worker does the heavy lifting in a single call: it transcribes, translates, preserves each speaker's voice server-side (no separate clone step), and returns a fully A/V-synced video — so there is no manual transcribe/clone/TTS/replace chain to manage and no duration-drift handling to do by hand.

Segmented / multi-language dub (per-range languages)

Use this when the user wants different languages on different parts of one video (e.g. first half Spanish, second half Japanese), or wants to translate only some sections and keep the rest in the original voice. Both are the same thing: a timeline of segments, each tagged with a language; any uncovered range keeps the original audio.

dub_video takes a segments plan instead of target_language (pass exactly one — they are mutually exclusive):

dub_video(source_video_url=<video_url>, segments=[
  {start_s: 0,  end_s: 30, target_language: "es"},
  {start_s: 30, end_s: 60, target_language: "ja"}
])

How to build the plan: the user needs to know where the content is before they can pick ranges, so transcribe first — extract the audio with extract_audio_from_video, then transcribe_audio(audio=<audio_url>, timestamps=true), show the user the timestamped segments, and let them say which time range goes to which language. Then assemble segments[] (seconds, ordered, non-overlapping) and make ONE dub_video call. There is no separate "video understanding" tool — the timestamped transcript is the understanding step.

Behavior of the segmented path:

• Shared voice across all segments. The source speaker is cloned once and every segment — in every language — is spoken in that same cloned voice, then the clone is recycled, all inside the one dub_video call. You never clone or delete a voice yourself.
• Keep-original. Any time range NOT covered by a segment plays the original audio (voice + background) untouched. To translate only parts of a video, list only the parts you want translated.
• Length-locked. Output stays exactly the source length (each dubbed range is speed-fit to its window), so boundaries line up with the original timeline.
• Provider. Mixed-language-per-range always uses the voice-cloning route automatically; the single-call whole-video dubbing route can't mix languages per range, so don't force a single-call provider for a segmented plan. Every covered language must be supported on the voice-cloning route — if one isn't, surface the error and consult references/language-coverage.md.
• Result. Same dubbed-video result; target_language echoes the covered languages comma-joined (e.g. "spa,jpn"), and no single transcript_language is returned (the track is multi-language). Lipsync (Step 2, default ON, ≤5 min) still runs on the whole dubbed video. For captions (Step 3), use the returned multi-language subtitles[] in caption_mode="manual"; auto re-transcription can't pick a single language for a mixed track.