Live video streaming basics
What is live broadcast
Using live broadcasting technology, you can not only watch video, but also create it and share it in real time. In this case, the information will be transmitted in the form of digital video signals with a small delay.
Sophisticated modern technology makes this process very simple. The fact that something is happening a long way away from you does not require any special effort on your part. You just click on “play” and enjoy your favorite match, take part in an event, watch a concert or take a lesson.
In this article we will analyze how it all works from the inside.
How the process works
The process of starting a live stream consists of five steps. First, you receive a stream from the camera on which the event is filmed. This stream is then encoded. After that, the flow is transferred to the end nodes. The data is processed by the content delivery network CDN and the output video is decoded and played back.
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Video stream capture
Frames are captured by the camera and converted into signals in formats suitable for streaming. Then the stream is encoded.
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Encoding
Captured data must first be converted into a different format before being transferred over the network, as their primary form is very heavy, which complicates the transfer. An encoder uses two steps to convert the video: compressing and resizing.
Video compression removes unnecessary visual data, such as duplicates and fixed frames.
Like, for example, you are filming a conference where speakers are standing in front of a monochromatic curtain. Video optimization is achieved by removing the double background visualization.
It is the encoder's responsibility to clean up the unnecessary data and that is the essence of their work.
This is done using the H.264, H.265, AV1 codecs. You can read more about the types of codecs in the text “What is video decoding and why is it important”.
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Packaging into a protocol
In order to transmit your content, at this stage the information is “wrapped” in a special real-time messaging protocol. There are quite a few video transmission protocols nowadays, RTMP, SRT, WebRTC, HLS, etc.
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Sending a stream to end nodes
So, your data is converted and ready to be transferred to the server.
To improve the quality of the transmission, the streaming server converts the information to a suitable codec or creates multiple versions so that the video can be received at the resolution supported by the recipient's device.
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What happens when data reaches CDNs or edge nodes?
A global network of distributed servers stores data in a cache format and sends it on behalf of the primary server. CDN speeds up the loading process, and due to the many servers, makes the delay minimal and reduces the load that goes to the main server.
So, we have outlined how live streaming works from the inside. To delve deeper into each of the processes, you can find more details on the blog.
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