Progressive download: What is it? How is live video broadcast online done? This page provides answers to all of these queries and more.
Corporate websites are becoming conscious that their users are much more likely to watch a 3 minute video than to read pages of text, thus many are now integrating informative “how to” and “introductory” video files in their internet pages.
Now that online video streaming is commonplace, we must wonder: How does it work?
First, we must classify video streaming into its three most popular configurations.
1) film streaming video on demand
2) A gradual download
3) Online live video
streaming video on demand When a website visitor requests it, a video is broadcast over the internet in this scenario. When you click the play button on a video you want to watch, this may be seen in action. With one major exception, this is extremely similar to the “Progressive download” that we previously discussed. The technology of streaming servers is used when a video is streamed. Making sure the movie is delivered as it should be is easy with steaming servers. We are able to do more than just transmit our movie when using the different streaming server technologies. With our streaming server, we can actually have “user interaction,” which would enable us to, for example, take a video viewer to a store so they may purchase anything they have seen and “clicked on” in the movie they are viewing.
While the video is playing, your video player will gradually download the entire file into your computer’s memory.
A capture device, such as a video camera, encoding software that transcodes or converts the video signal from the camera into a web-compliant video format, and a streaming server are all necessary for live video streaming.
The encoder receives the video data from the camera and transcodes it before sending it to the streaming server (often over the internet) using one of the several streaming protocols. The streaming server will then transmit the encoded video to your viewers via the internet, usually with a little delay of no more than 7 to 20 seconds from what is actually happening.
MPEG4: What is it? MPEG4 was created to support video playback across a number of different systems. It is compatible with HD TVs, PDAs, mobile phones, and desktops.
Despite the fact that there are numerous distinct video formats available online, all streaming—whether it be live, on demand, or progressive download—uses the same coding algorithms developed for MPEG2, the predecessor to MPEG4.
The video stream and the audio stream are sent through separate “data channels” that make up MPEG4. It is not specified how many data channels there are. Typically, we have a video transport channel for streaming video, up to 8 channels for audio, typically MP3 or AAC (Advance Audio Codec), a channel for subtitles, and a data channel for sending and receiving information to and from the streaming server.
The delivery technique is the reason video can be successfully transmitted over the internet. Frame by frame delivery is common in video, particularly in movies. This is a holdover from older filmmaking techniques where the entire image was shown to the audience in each frame. The human eye perceives continuous movement because these frames are played back one after another so quickly.
I-frames and P-frames make up compressed MPEG4 video. A P-Frame is an update of an I-Frame, and I-Frames are essentially frames that contain all the data required to display a frame. The decoder then displays a succession of P-Frames that update movement and other changes after an I-frame. As a result, the video size is drastically decreased. This explains why, occasionally, blank squares appear in pictures when viewing videos online. This is because the decoder is unable to update those portions of the video because the P-Frames were not received in time.
Describe a codec Information can be encoded and decoded using a codec. In order to compress video and audio data while maintaining the highest level of quality, an encoder is used by all of the different online video formats. The video is then sent over the internet, where it is decoded into or as close to its original format as possible before being played by the client.
