How must the first-frame image be submitted?
Use image_url to submit a publicly accessible image, and set action to image_to_video and model to happyhorse-1.1-i2v. The image will serve as the first frame of the video; use prompt to supplement subsequent actions, environmental changes, and camera movement, without needing to redescribe all static details.
Can I specify portrait or square videos?
The output aspect ratio for first-frame tasks will follow the image as closely as possible, so there is no need to pass an additional ratio. To create portrait or square content, first prepare a first-frame image with the corresponding composition; it is best to leave safe space around product labels, people's heads, and other important elements, then check the final video's actual frame.
Can it use multiple reference images to maintain character consistency?
This model starts generation from a single first-frame image and is not a multi-image reference mode. When you need to combine character, clothing, or prop references, choose happyhorse-1.1-r2v; if the main goal is to make an existing image start moving without reorganizing the scene, i2v better matches the task structure.
What resolutions, durations, and audio capabilities are supported?
This endpoint offers 720P or 1080P, with durations of whole-number 3–15 seconds; native video specifications are 24 fps, MP4, with audio support. Audio generation and precise dubbing control are different capabilities; retaining the original video audio or using reference audio input is not supported by this model.
How do I get the finished video after submission?
You can set async=true, save the returned task_id, and then query through /happyhorse/tasks; you can also provide callback_url and wait for a completion notification. Result statuses include pending, succeeded, and error, and successful results include video_url; do not assume the video has finished generating just because you have obtained a task ID.