FLUX 3 Start-End to Video: Image-to-Video
Generate a video transition between a start and end keyframe with native audio using FLUX 3. Try free — pay per generation, no subscription.
Generate a video transition between a start and end keyframe with native audio using FLUX 3. Try free — pay per generation, no subscription.
About this model
FLUX 3 Start-End to Video generates a video transition between a start and end keyframe, with optional native synchronized audio, using Black Forest Labs' unified image/video/audio architecture. Describe how the two frames should connect and FLUX 3 fills in physically plausible motion between them — useful for precise camera moves, lighting transitions, and object transformations that FLUX 3 Image to Video alone can't pin down.
Cost analysis
| Provider | Cost | Notes |
|---|---|---|
| muapiapp | $0.25/sec (720p), $0.42/sec (1080p) | Pay-per-generation pricing, no subscription required. Audio generation included at no extra charge. |
| Fal.ai | Not available | FLUX 3 Start-End to Video is not yet listed on Fal.ai. |
| Replicate | Not available | FLUX 3 Start-End to Video is not yet listed on Replicate. |
Pay-per-generation pricing, no subscription required. Audio generation included at no extra charge.
FLUX 3 Start-End to Video is not yet listed on Fal.ai.
FLUX 3 Start-End to Video is not yet listed on Replicate.
** Competitor pricing is estimated based on similar model architectures and usage tiers.
Configuration schema
| Parameter | Type | Description | Default |
|---|---|---|---|
| Prompt | string | Describe the action or transformation connecting the start and end images. | The scene morphs from a busy daytime street to the same street quiet at night, streetlights turning on. |
| Start Image URL | string | Initial visual keyframe for the transition. | https://d3adwkbyhxyrtq.cloudfront.net/ai-images/186/712345784292/4a8c5c70-abcc-4920-873e-b0e219986453.jpg |
| End Image URL | string | Final visual keyframe for the transition. | https://d3adwkbyhxyrtq.cloudfront.net/ai-images/186/712345784292/4a8c5c70-abcc-4920-873e-b0e219986453.jpg |
| Aspect Ratio | Enum (6 options) | Aspect ratio of the output video. | 16:9 |
| Duration | int | Video duration in seconds. | 5 |
| Resolution | Enum (2 options) | Output video resolution. | 720p |
| Generate Audio | boolean | Whether to generate synchronized native audio for the video. | true |
Describe the action or transformation connecting the start and end images.
The scene morphs from a busy daytime street to the same street quiet at night, streetlights turning on.Initial visual keyframe for the transition.
https://d3adwkbyhxyrtq.cloudfront.net/ai-images/186/712345784292/4a8c5c70-abcc-4920-873e-b0e219986453.jpgFinal visual keyframe for the transition.
https://d3adwkbyhxyrtq.cloudfront.net/ai-images/186/712345784292/4a8c5c70-abcc-4920-873e-b0e219986453.jpgAspect ratio of the output video.
16:9Video duration in seconds.
5Output video resolution.
720pWhether to generate synchronized native audio for the video.
trueDeveloper documentation
Upload a start image via image_url and an end image via end_image_url.
Write a transition prompt — describe the action or transformation connecting the two frames.
Configure output — set resolution (720p or 1080p) and duration (5–20 seconds); aspect_ratio is optional.
Toggle generate_audio for synchronized native audio at no extra charge.
Submit the request:
curl -X POST https://api.muapi.ai/api/v1/flux-3-start-end-to-video \
-H "x-api-key: YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{"prompt": "The scene morphs from a busy daytime street to the same street quiet at night", "image_url": "https://example.com/start.jpg", "end_image_url": "https://example.com/end.jpg", "resolution": "1080p", "duration": 5, "generate_audio": true}'
/api/v1/predictions/{request_id}/result until completed.Frequently asked
It generates a video transition between two keyframes you supply — a start image and an end image — with optional native synchronized audio.
FLUX 3 Image to Video animates from a single starting frame with open-ended motion. Start-End to Video locks down both the first and last frame, giving precise control over where the clip ends up.
Yes, native synchronized audio can be toggled with the `generate_audio` parameter at no extra charge.
720p and 1080p resolution, with durations from 5 to 20 seconds, billed rounded up to the next whole second.
Muapi bills $0.25/second at 720p and $0.42/second at 1080p, rounded up to the next whole second, capped at 20 seconds.