Walt's Overview on Internet Video
Thanks in large part to the popularity of video sharing and hosting sites like YouTube, websites are using rich media including video clips to spice up their websites more than ever.
There has long been a desire to watch videos online, but there've always been significant technical challenges to overcome.
The first challenge has always been with the sheer size of video files. Video files tend to be quite large, and they can easily end up taking 100s of Megabytes of space and even many Gigabytes of space depending on the length of the video. Most hosting providers provide a limited amount of space per client, and one video file can use up a large portion of the space allotted.
The second challenge is that a video stream uses up an enormous amount of bandwidth. Here is a list of the bandwidth required to stream video at different quality levels:
* 2 Mbit/s — VHS quality
* 8 Mbit/s — DVD quality
* 55 Mbit/s — HDTV quality
To put those bandwidth amounts in perspective, many DSL lines still operate at approximately .5 Mbit/s to a little over 1 Mbit/s Cable lines generally provide faster speeds, but available bandwidth varies and the network can slow depending on traffic generated by other users in the neighborhood that are connected to the same pipe.
Video bandwidth issues aren't just an issue for the end user and their ISP -- they also effect the server-side -- the party hosting the actual files whose server must send the files to people requesting it. Commercial T1 lines designed and sold primarily to businesses to provide network access, serve files and websites only operate/serve at 1.5 Mbits/s (not even enough for a VHS quality stream). Serving a video stream to one user can take up the entire pipe, and trying to serve video streams to multiple users would bring the entire network to a crawl. Most hosting providers will limit the actual total amount of bandwidth used per month, and charge for overages.
The file size and bandwidth issues are the reasons most videos on the web appear at a lower quality and dimensions than standard VHS. The running length of the video, the dimensions that the video is shown on the screen, and the quality level of the video are often limited to generate smaller file sizes and files that use lower bandwidth rates when streamed.
Various video "codecs" have been developed to encode/decode digital video data streams into smaller sizes that use less bandwidth. Codecs use various compression algorithms to accomplish this task. Improved video codecs have helped accelerate the proliferation of videos on the internet.
The final hurdle has always been what file format should the video be in, and what player would be available on the home users' computer to play the file? Windows Media Player has been a choice for AVI files and WMF files. Whereas, the QuickTime program was used to play MOV files. Various different players on home users' computers complicated the serving of video files and the programs often required 3rd party downloads as they were not necessarily preinstalled on the computers and these downloads were often operating system specific.
Adobe's Flash authoring program's inclusion of video capabilities has solved many of these problems as the free Flash Player program comes preinstalled with almost all browsers, and is generally available to 98% of internet users. YouTube's video sharing site, uses a Flash player to show their videos.
To work in Flash, other video file formats must first be converted into the FLV file format which can be played with a Flash video player control (which is embedded in a SWF file).
To overcome the bandwidth issues associated with serving videos on the web, most websites have turned to YouTube and similar video hosting services. Such companies are dedicated and designed around hosting videos, and they have the infrastructure and equipment necessary to do so.