The process of streaming video is time based and multi-processed. There are three parts: the encoded bits (called AAC), the container that holds the bits together in encoded video data (called FLV or MP4) and the transport that moves it from the server to the player (called RTMP). Because video files are so large, they are broken down into smaller pieces and send individually to their specific location and the M3UP tells the player the order in which to play the stream. The data gets where it needs to be using rules called protocols, which say how the data will travel from one device to another- for example HTTP.
Video starts out as raw files, which are high quality digital files that are not digitized and have not been compressed or distorted in any way. However, as I said, video files are very large. While they break the data into parts, they also make the files smaller. Two ways this can be done are:
1. Making the picture smaller so it doesn't fill the whole screen. You can see this when you are watching a video; you lose quality when you make it full screen. Below you can see Dwight from The Office, both in the smaller frame and stretched to full screen. Although it is not super apparent in these photos, this stretching to full screen does affect the quality when you're watching.
2. Reducing the frame rate. A video is a series of still images, so you can reduce the number of total images so that it takes less data to recreate them. Sometimes you can see videos flicker because eyes and brain can sense the transition between pictures.
Making files smaller requires codec, compression/decompression software, which discards all unnecessary data and lowers the resolution. This reduction of quality depends on a number of factors, one of which being bitrate, which is the speed of transfer from the server to the computer. For example, the bitrate of a tv broadcast is 240,000 kilobits, whereas dial-up internet is 56 kilobits. You can also create files that stream differently at different transfer rates, which is called multibitrate encoding. After going through this complex, efficient process of streaming, your computer discards the data as you watch. Who would've thought all this work goes into streaming The Office on Netflix!
References:
http://computer.howstuffworks.com/internet/basics/streaming-video-and-audio2.htm
https://www.youtube.com/watch?v=AeJzoqtuf-o
I always watch streaming videos online but i've never stopped to think of ho it actually works.It turns out it's really fascinating and how the data is processed and configured.Do you think we will still use the same methods with 4k video streaming that requires huge amounts of data to be processed or are we going to be able to find a new way to do that ? Thanks for the article
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