# Set video layout (/en/realtime-media/on-premise-recording/build/customize-the-recording/layout)

> For AI agents: see the complete documentation index at [llms.txt](/llms.txt).

This guide shows you how to configure the video layout during composite recording using the On-Premise Recording SDK.

## Understand the tech

In composite recording mode, the SDK renders the final video on a canvas that includes multiple user video streams. Each stream is placed in a defined region of the canvas. The canvas acts as the background, and you specify the dimensions and position of each user’s video.

![Composite recording canvas with user video regions](https://assets-docs.agora.io/images/on-premise-recording/user-region-canvas-diagram.png)

<CalloutContainer type="info">
  <CalloutDescription>
    The aspect ratio of a user's video must match that of the assigned region. If the aspect ratios differ, the SDK crops the video, which can result in image loss.
  </CalloutDescription>
</CalloutContainer>

## Prerequisites

Before using layouts, complete the steps in the [Quickstart](/en/realtime-media/on-premise-recording/quickstart) guide to integrate the SDK and set up basic recording.

## Implementation

To configure the layout, call the `setVideoMixingLayout` method and pass a `VideoMixingLayout` object that defines:

* Canvas dimensions and frame rate
* Background color or image
* Layouts for each user's video

```cpp
struct VideoMixingLayout recorderLayout;
recorderLayout.canvasWidth = 1280;
recorderLayout.canvasHeight = 720;
recorderLayout.canvasFps = 25;

UserMixerLayout layout[2];
layout[0].userId = "1234";
layout[0].config.x = 0;
layout[0].config.y = 0;
layout[0].config.width = 640;
layout[0].config.height = 360;

layout[1].userId = "5678";
layout[1].config.x = 720;
layout[1].config.y = 270;
layout[1].config.width = 540;
layout[1].config.height = 320;

recorderLayout.userLayoutConfigNum = 2;
recorderLayout.userLayoutConfigs = layout;
recorder->setVideoMixingLayout(recorderLayout);
```

The sample code creates the following composite layout:

![Composite layout](https://assets-docs.agora.io/images/on-premise-recording/composite-layout.svg)

## API reference

* [`setVideoMixingLayout`](/en/api-reference/api-ref/on-premise-recording#setvideomixinglayout)
* [`VideoMixingLayout`](/en/api-reference/api-ref/on-premise-recording#videomixinglayout)

    
  
      
  


## Platform-specific versions
- [Linux C++](/en/realtime-media/on-premise-recording/build/customize-the-recording/layout/linux-cpp.md)
- [Linux Java](/en/realtime-media/on-premise-recording/build/customize-the-recording/layout/linux-java.md)