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.
Demo Video:
To start with, please follow the steps below.
- 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.
- Upload a Source Video
- Drag and drop the file into the upload box
- OR
- Click the box and select your file manually

- 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
- 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.



- 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.


- 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)

- 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

- Download the video
- Wait for the video to be rendered completely


- Click the video
- Click Download Video
