Mix To An Exact Duration + Restored Video Editor Ops

April 21, 2026

Note — April 23, 2026

Several of the video-generation operations restored here (retake, extend, IC-LoRA, ID-LoRA, upscale, generate-from-audio) returned to a "temporarily unavailable" state two days later when Video Lab moved to Runway Gen-4.5. The mix-to-duration change is unaffected and still works as described.

The audio-mix step now accepts a target duration. Want a 30-second cut from a longer take? Pass the target duration and it's hard-trimmed in the same call — no chained ffmpeg steps. A handful of video-generation ops that had been silently returning "not found" errors were also re-wired this day, though some were rolled back two days later (see the banner above).

What's actually new and stable

• mix_audio accepts a target duration. Pass target_duration: 30 and the output is hard-trimmed to 30 seconds. "Mix the narration over this B-roll and cut it to exactly 30 seconds" runs in one call.
• The mix-only variant accepts the same parameter when you want a finalized audio bed without video.

When you'd notice it

You've got a 45-second narrated take and need to ship a 30-second version. "Mix this narration with the B-roll, trimmed to exactly 30 seconds." One call, no follow-up "now trim to 30s."

Try it

• "Mix the voiceover with this background track and hard-cut to 30 seconds."

Heads up

target_duration is optional. Omit it and mix behaves as before — uses the longest input's duration.