RECAST – Step-by-Step Guide

Recast is part of the Synthesys suite and is designed to help users:

• Take an existing source video
• Replace or generate a target character (face/avatar)
• Rewrite or modify voice, script, and language
• Produce a new “recast” version of the original video

In simpler terms, it is a video re-creation tool powered by AI avatars, where you can change who appears in the video and what they say, while keeping the original motion or structure.

To start with, please follow the steps below. 

1. Prepare your Video

Make sure your video:

• Shows only one person
• Has clear lighting and visibility
• Is steady (not too shaky)
• Is under 30 seconds
• Saved as MP4
• File size is ≤ 100MB

💡 Tip: A simple clip of someone moving, talking, or gesturing works best.

2. Upload a Source Video

• Drag and drop the file into the upload box
• OR
• Click the box and select your file manually

3. Wait for Processing

• The system may take a few seconds to upload and analyze
• If there’s an issue (wrong format, too large, etc.), it will prompt you

4. Select or define the “Target Character”

Lets you modify the appearance of the person in the video.

• After upload, go to “Target Character”
• Choose:
  • A preset avatar/character
  • OR upload/select your own (depending on the tool)
• If you want to change the actor’s character using a prompt, click “Grab from Video” first. Then enter your instruction in the “Edit Target Character” field.

Example prompt:

“Change only the actor’s face to that of a man with long hair, not wearing glasses, and wearing a blue shirt.”

• Once you’re done, click “Apply Edit”. The system will then generate and apply the updated face to your video.

5. Edit Voice Script (Limits video to 20s)

This replaces or adds spoken dialogue.

• If you want to change the script for the source video, click Enable from Edit Voice Script as shown below and add your own script. 

6. Audio & Sync Settings

• Turn ON Voice Selection
• Pick a voice from dropdown
• (Optional) Turn ON Translate Language and choose a language
• Toggle Add Captions ON

Choose:

• Style (Style 1, etc.)
• Language (e.g., English)

7. Generate video

• Click Confirm & Generate
• Here, you can see the total credit cost of your video, calculated at 24 credits per second.
• Wait for processing (can take a few minutes

8. Download the video

• Wait for the video to be rendered completely

• Click the video 
• Click Download Video