QBurst

In my previous article, we discussed all the video formats that are predominantly used in web. Here, we are going to see how these different formats are effectively delivered in the web. There are three methods that genuine developers have used so far to bring video into web. Let’s list them chronologically and get to know them in simple terms.

• Downloading

This traditional method is the one in which the user will have to wait for the file to download in his local machine and then play the file in a player. The user will not be able to view the video unless the file is downloaded completely. He must also choose the right player to play the file. Right player, in the sense: the one which understands the codec used by the video file.

Accomplishing this method in a webpage is pretty simple for a developer. He has to upload the file in the web server and provide a link to the file in the webpage. An alternate method is to embed the file in the webpage with a player using a HTML code. When the user clicks the link, the download begins. This method is commonly referred to as HTTP Streaming. This method is still used by a number of sites. And yes the point is it does not cause any trouble if the site traffic is low. One notable inability of this traditional method is that no live streaming can be done since there can never be a complete file during live transmission.

• Streaming

In the case of a streamed video, the file is sent to the end user in a continuous stream which allows him to watch the video as and when it reaches the local system. Streaming has gained so much popularity with live telecasts. When you browse through the web you will find podcasts and webcasts delivering video. Both of these use streaming method to deliver video. A webcast is mostly a single file that is played live or on demand whereas a podcast comes as a series and is delivered on demand. Another widely used streamed application in countries like US and UK is the internet television. Let’s break down streaming and get into the next level.

o   Progressive streaming

o   True streaming

Progressive streaming is used for on demand videos. If the video is delivered progressively, then the video file gets saved in the local system and plays from the local. Once the video is done playing, it will still be available for replay. This is not the case with true streaming which plays the file without saving it in the local. So once the player has completed playing once, it will not be further available for replay. A perfect example would be a live match that is telecasted through the internet.

Streaming is complex which could be understood only when tried. Protocol selection is one which could add to the complexity. Unicast protocols may be a feasible one for modest websites but more number of concurrent users could upset the system unless there is sufficient storage provided. Multicast protocols compel to forgo on demand function which might not be possible for all. UDP (datagram) may not be efficient as the others.

The data (video files) may be stored in-house or outsourced. Most of the companies outsource the complete process in order to avoid complexities. A few major products available to service video on web are FMS (Flash Media Server), Wowza, QTSS (Quick Time Streaming Server). This is another area which I will cover in my next article. Now we’ll move on to the next method.

• Progressive Downloading

The method of progressive download is similar to Streaming. However, this method uses a HTTP protocol. Also there is difference in how data is interpreted at the user’s end. YouTube.com uses progressive download for its video service. Gaining access to the video is also simple as the file is mostly saved in the temp folder. The file could be stolen by anyone and this has given rise to piracy and security problems. In the streaming method, a similar situation will not arise because at no time will the entire file be downloaded locally.

I hope to have put these video concepts in simple terms. Do contact me if you like to know more about video on web.

Tags: Downloading, HTTP, Protocol, Streaming, Video, Web, YouTube

This entry was posted on Wednesday, October 14th, 2009 at 3:30 pm and is filed under Business, Career, General, Web. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.