Introduction

Expand Video reimagines and reframes existing videos into different formats. 

Resizing an asset with traditional cropping often leads to important details being removed. Instead of removing details, Expand Video adds beyond the edges of an input video to generate into a new format.

This article outlines the steps to create with Expand Video, different prompting approaches, and more.

 

Spec Information

 

Article Highlights

• Tall videos will result in a landscape output, wide videos will result in vertical output, and square videos allow you to choose the output size.
• Expand Video works great in most cases without a prompt. Include a text or image prompt for more control.
• Use an outpainted image of the video’s first frame for best results when using a guiding image.
• Using an outpainted image that doesn't exactly match may cause a brief visual jump.
• You can expand a video multiple times by clicking the dropdown next to Reuse settings and then selecting Expand Video on a previously expanded output.

 

Best Practices for Input Videos

• Close to a traditional aspect ratio
• Minimum of 620 pixels in width and height
• Subject (if any) is close to the center of frame
• No graphics or text
• Used with a text prompt or matching guidance image

 

Step 1 – Selecting a Video to Expand

Begin by navigating to Generative Session in your Runway Dashboard and select Expand Video from the left-hand tool bar.

Next, select the video to expand. You can choose an existing video directly from your Assets, or upload a new video by dragging and dropping. Use a video that follows the best practices for 

Expand Video will reframe the input video to either a landscape or vertical format, depending on the dimensions of the input video you select:

Input Video	Output Aspect Ratio
Landscape	768x1280 (vertical)
Vertical	1280x768 (landscape)
Square	768x1280 or 1280x720

In summary, choosing an input video with a larger width than height will create a vertical output, and a larger height than width will result in a landscape output. You can choose between a vertical or landscape output when using a square input video.

Input videos must be a minimum of 620 pixels in width and height. 

Videos that are much narrower than traditional aspect ratios in either direction are not accepted. For example, a 620x1280 video is 100px narrower than a traditional 9:16 (720x1280) vertical video and would result in an error upon selection.

After selecting the video, you’ll see a boundary box preview that indicates the updated dimensions you’ll receive after running the generation. 

You can choose the desired output size with the dimension selection button when using a square input video:

 

Step 2 – Configuring the Expand Video Prompt

Expand Video will work well in most cases without a prompt, but including one will give you more control over the output.

Using a Text Prompt

When writing your Expand Video prompt, focus primarily on describing what you want to see in the expanded areas.

While the input video will guide most of the scene details automatically, you can make brief references to it to ensure visual consistency. However, avoid detailed descriptions of the existing video content, as this may lead to unexpected results.

 

Using a Guidance Image

You can also add a guidance image by selecting the Add First Frame icon or dragging and dropping an image to the canvas.

Using an expanded image of the input video’s first frame will provide the best results when using a guidance image. You do not need to include a text prompt when using an input image to guide the generation.

If you use an image that doesn't exactly match or align with the video's first frame, it may cause a brief visual jump when the output video starts playing. If this occurs, ensure that your image aligns properly with the video or use a text prompt instead. Alternatively, you could also trim the first frame from the video.

Below are examples of the same input video with different prompting approaches:

 

Step 3 – Generating and Reiterating the Output

Before beginning the generation, you can hover over the Duration icon to see the estimated credit costs.

After confirming the credit costs, click Generate to start processing the Expand Video generation.

Your generations will be scrollable through your session as you continue to generate. You can also access completed videos in your Assets, where they will save to the Generative Video folder by default.

 

Expanding a Video Multiple Times

You can expand a video multiple times by clicking the dropdown next to Reuse settings and then selecting Expand Video on a previously expanded output.