Overview

Zixi Broadcaster’s HTML overlay feature overlays a dynamic HTML page on the video stream during the transcoding process. As part of this process, the images from the HTML page are “burned” into the video. The process uses Chromium Embedded Framework (CEF) to render the HTML page and then the image is passed on to the transcoder to overlay on top of the raw video frame, which is then encoded. The overlay process occurs at the configured frame rate in the transcoder, assuming the CPU that is used for the CEF process can keep up. Animations on the HTML page can be rendered on the video stream. However, currently audio on the HTML page is not introduced into the transcoded stream.

There are two processes that are handled by the Zixi Broadcaster:

CEF (HTML Rendering) - CEF uses the CPU to render the HTML page at the designated frame rate during transcoding.
Transcoding - The transcoding process may use either NVIDIA GPU or a CPU. The transcoding includes the following processes: video decoding process, the page overlay insertion, and the video re-encoding.

It is expected that CPU usage will be significantly higher when using the HTML overlay feature versus a normal transcode because of the CEF rendering process and the handling of raw video frames.

To enable the HTML overlay feature, you will need to install the CEF plugin and the Xserver components on the Zixi Broadcaster machine. This document describes the process of installing these components on an existing Zixi Broadcaster. To install a new Zixi Broadcaster, follow the instructions in the Zixi Broadcaster Installation Guide.

The examples used in this document have been tested with Zixi Broadcaster V17 on AWS EC2 instances with Intel/AMD X86 processors using Amazon Linux 2 OS. For other machine types and operating systems, you will need to adjust the installation process.