Speaker 1: Whether you are watching your favorite show on Netflix or a funny video on YouTube, video streaming is everywhere. In this video, I will discuss what video streaming is, how it works, and how it has revolutionized the way we watch videos. So let's dive into it. Video streaming is a process that allows you to watch videos online without having to download them first. Generally, pre-recorded video files are transmitted through video streaming, but it's also possible to stream live broadcasts such as YouTube or Facebook live streams. When you click play on a video, it begins streaming from the server to your device in real-time. The video and audio files are broken down into small pieces called packets, which are then transmitted to your device over the internet. These packets are then reassembled by your device into the video and audio files that you see and hear on your screen. There are several types of video streaming that are commonly used for different purposes, but usually they are categorized into live stream and on-demand streaming. Live streaming involves broadcasting live video and audio content in real-time over the internet. This can include events, concerts, sport matches, news broadcasts, and more. Live streaming can be done using various technologies and protocols, including RTMP, Dash, and more. On-demand streaming is the most common type of video streaming, and it involves delivering pre-recorded video and audio content to viewers over the internet. This can include movies, TV shows, and other types of content that viewers can watch at any time. On-demand streaming can be done using various technologies and protocols, including HTTP streaming, Dash, and more. Peer-to-peer is also a type of streaming that involves distributing video and audio content to viewers using a peer-to-peer network, where viewers share their own bandwidth and computing resources to help distribute the content. In fact, this I have covered in one of my previous system design videos. One important aspect of video streaming is bitrate. Bitrate is the amount of data used to represent a piece of audio or video. The higher the bitrate, the more information is transmitted, and the higher the quality of the audio or video. This means that a video with a high bitrate will generally look and sound better than a video with a lower bitrate. Think of bitrate like a water hose. The more water that flows through the hose per second, the more quickly the hose can fill up a bucket. Similarly, the higher the bitrate, the more data can be transmitted per second, resulting in a higher quality audio or video. However, higher bitrates require more storage space and bandwidth to transmit. This is why streaming services use the technique Adaptive Bitrate Streaming. Adaptive Bitrate Streaming or ABS is a technique that adjusts the quality of the video based on the viewer's internet speed to ensure that the video can be streamed smoothly without buffering or interruptions. ABS works by encoding the video at multiple bitrates and allowing the viewer's device to automatically switch between the different bitrates based on their internet speed. This ensures that the video is streamed at the highest quality possible without any buffering or interruptions. In the context of video streaming, a client refers to the device or application that is used to view the video content. This can include a desktop or laptop computer, a mobile phone or tablet, a smart TV, or any other device that is capable of connecting to the internet and playing back video. Now when a client requests a video stream, the server responds by providing the client a list of available bitrate versions for the video. The client then selects the appropriate bitrate version based on the current network conditions, such as available bandwidth, and begins playback. As network conditions change, the client may automatically switch to a different bitrate version that is better suited to the new conditions. Hence the name Adaptive Bitrate Streaming. ABS can be implemented using various protocols such as HTTP Live Streaming or HLS, Dynamic Adaptive Streaming over HTTP, Dash, Real-Time Messaging Protocol, RTMP, or any other protocol that allows delivery of video and audio over the internet in chunks of varying bitrates. Dash for example is an open standard for ABS that is designed to work with HTTP. It allows by dividing the video into small segments and delivering them over HTTP with the viewer's device automatically switching between the different bitrate versions of each segment based on the available bandwidth. Dash is widely used by major streaming services like Netflix, YouTube, and Hulu. Video streaming is an increasingly important topic in system design interviews for a number of reasons. Firstly, video streaming has become a critical component of many modern applications, from video sharing sites like YouTube to live sharing platforms like Twitch and Facebook Live. Additionally, video streaming requires understanding of some basic protocols and involves complex interactions between various components including servers, networks, and client devices which makes it a great topic for assessing a candidate's ability to design and optimize distributed systems. You will see video streaming in action in my upcoming video on YouTube system design.