Runway: Gen-4.5

Runway Gen-4.5 is a video-generation model with text-to-video and image-to-video modes. It can follow a brief that describes scene composition, subject action, camera choreography and a sequence of events. The useful result is a short generated shot that can be reviewed, retained or assembled with other footage.

Choose the input mode for the shot

Text-to-video starts from a written scene description. Include both the visible content and the motion: subject, setting, lighting, framing, action and camera behavior. This mode is useful for a new scene, B-roll, background plate or visual concept where the starting frame does not have to reproduce a supplied image.

Image-to-video starts from an image that acts as the first frame. That image supplies composition, subject matter, lighting and style. Focus the written prompt on what should happen next: the subject's action, movement in the environment, camera motion and the progression of the shot.

Prepare a clear image with the important details already visible. Blurred faces, hands or other artifacts can become more noticeable when animated. A reference that suggests rapid motion through dust or motion blur can also conflict with a prompt that asks for a stationary subject.

Describe visuals and motion directly

Use clear natural language and positive descriptions of the intended result. A text-to-video brief can state the camera view, subject and action first, then add the scene treatment. A detailed description is useful when the shot has defined requirements; a simpler one gives more room for exploration. There is no ideal word count that replaces clarity.

For example, describe a close view of a brass desk lamp as its light turns on, followed by a slow camera move that reveals a notebook beside it. State the visible materials and light for text-to-video. If a supplied image already establishes those details, the image-to-video prompt can concentrate on the light change and camera reveal.

Avoid contradictory directions. A locked-off view with subtle subject motion is different from an energetic handheld tracking shot. Add the details that define the useful shot rather than a long list of unrelated visual styles.

Camera terms and sequenced action

The maker's camera guide distinguishes framing, angles, movement and focus. A close-up changes what fills the frame, a low angle changes perspective, a pan rotates the camera's view and a tracking move follows a subject. A rack-focus instruction shifts the focus between visible subjects. State what should be in view or revealed as the movement develops.

Sequential prompts can express events in ordinary language or with rough timestamps. Those timestamps guide the order and approximate timing; they are not a guarantee of frame-exact execution. Give the requested actions enough time to occur naturally within the selected clip duration.

For a static shot, describe the motion that belongs inside the frame and reinforce the intended still camera. The maker notes that completely motionless views can be difficult, particularly for some wide or establishing shots. Review small unwanted movements in the actual result rather than assuming a static-camera phrase makes them impossible.

Duration, dimensions and frame rate

Gen-4.5 supports clip durations from 2 to 10 seconds. A longer choice can accommodate several ordered actions, while a brief reaction or reveal can use a shorter shot. Its documented output is 720p, with 24 or 25 frames per second in the maker's generation workflow.

The text-to-video specification lists 16:9 at 1280 × 720 pixels. Image-to-video additionally lists 9:16 at 720 × 1280, 1:1 at 960 × 960, 4:3 at 1104 × 832, 3:4 at 832 × 1104 and 21:9 at 1584 × 672. Keep the mode and actual dimensions together rather than assuming both input modes offer the same aspect-ratio set.

An image's ratio can establish the default composition, and changing it can crop the input. Check the subject's placement before judging motion: a correct action is not useful if a key part of the source image has been cut out.

Build a longer sequence from completed shots

For image-led work, the maker describes continuing a sequence by using a completed clip's last frame as the image input to another generation. The clips are then combined in a video editor, with their shared frame and timing handled in the edit. This is a sequence of separate shots, rather than one unlimited-duration generation.

Retain the end frame and the corresponding brief so that the next shot starts from the intended visual state. Inspect continuity in the joined footage, including subject appearance, camera direction and the transition between clips.

Retain and review the production artifact

After generation, review the full clip and retain the completed output. The producer's workflow also provides separate upscaling and production-export choices such as ProRes or a PNG sequence. Those are additional workflow options; the native generation dimensions remain distinct from a later upscaled result.

Use Gen-4.5 for cinematic concepts, animated visual ideas, B-roll and short scene development. Keep the prompt, input image where used, duration, mode and returned clip together. Check action order, camera behavior, subject details, unwanted cuts and the intended framing, then make a focused correction to the shot.