You can use Azure Virtual Network to integrate your Azure Container Instance with your client's private network. This will allow you to securely access the cameras' feeds from your Azure Container Instance.
You can use either a private endpoint or a private link to connect your Azure Container Instance to your client's virtual network.
A private endpoint is a special network interface for an Azure service in your virtual network. When you create a private endpoint for your resource, it provides secure connectivity between clients on your virtual network and your Azure resource. The private endpoint is assigned an IP address from the IP address range of your virtual network. The connection between the private endpoint and the Azure service is a private link.
A private link is a secure connection between your virtual network and an Azure service. It enables you to access the Azure service over a private IP address from your virtual network.
You can find more information about virtual network integration of Azure services for network isolation in the following link.
Please let me know if you have any questions or concerns about this suggestion.