As bandwidth has grown so has the size and complexity of web sites. With the advent of YouTube, Vimeo and the like video streaming media has grown in popularity. We survey the video landscape to see how video size, duration, and usage on the web have grown over time.
The duration of the mean web video has grown significantly since 1997. In 1997 the length of the mean web video was a mere 45 seconds long (Acharya & Smith 1998). In 2003 the mean web video grew to about 120 seconds long, or 2 minutes (Li et al. 2005). By 2007, the median video was 192.6 seconds in duration (Gill et al. 2007). In 2010 the mean web video was 270 seconds long in duration (Karki 2011). Meanwhile, the bitrate and dimensions of the mean web video has grown from 200Kbps in 2003 to 300Kbps in 2010. So the file size of the mean web video has more than tripled from 2003 to 2010.
Figure 1: Growth in Web Video Duration
For his Master's Thesis "Fresh Analysis of Streaming Media Stored on the Web" at Worcester Polytechnic Institute Rabin Karki customized a crawler to analyze over 20 million URLs (Karki 2011). Karki found that Advanced Video Coding (H.264) made up about 28% (27.6%) of the videos codecs found (see Figure 2). H264 is used in a variety of popular applications including YouTube, iTunes, Adobe Flash and Microsoft Silverlight, broadcast services, and cable television services. Second place goes to the Flash Video (flv) codec, a container format used to deliver video on the Internet using Adobe Flash Player versions 6 to 10. This technique is used in YouTube, Hulu, Google Video, Yahoo! Video, and MetaCafe. MPEG4 came in third at 19.1%, following by versions of Real Video and Windows Media Video codecs. A total of 36 video codecs were encountered in the analysis.
Figure 2: Video Codec Usage
Source: Karki 2011
The median file size of all the videos analyzed was 8MB. The median encoded video bitrate was 0.3Mbps. This is up from the 200Kbps encountered in the 2003 study by Li et. al, but well below studio quality videos (3-6 Mbps) and HDTV quality videos (35-34 Mbps). About 55% of videos encountered had resolutions of 320x240, about 30% had resolutions above 320x240 and at or below 640x480 pixels.
As the duration, quality, and size of the average video grows so does the number of users. A PEW Internet study found that 71% of the online Americans use a video sharing site, up from 66% a year ago, and 33% in 2006 (see Figure 3).
Figure 3: Video Sharing Site Usage
Rural Americans are the segment most impacted by the spread of broadband with rural video sharing site usage more than tripling from 2006 (21% usage) to 2011 (68% usage, see Figure 4).
Figure 4: Visits to Online Video Sites Increasing Most in Rural Areas
As bandwidth connectivity grows, so does the size and complexity of the average web site. Audio and Video files are growing steadily with bandwidth. The duration of the mean web video has grown by 2.35 times from 2003 to 2010. With the average bitrate growing from 200Kbps to 300Kbps over the same time period, and the dimensions growing as well, the file size of the average web video is growing at a faster clip (the mean videos file is at least 3.375 times larger in 2010 than it was in 2003). The codecs are also changing over time. In 2003, streaming multimedia was dominated by Real Network's RealMedia, Microsoft's Windows Media, and Apple's QuickTime. Now these three codecs have been replaced by newer media formats, with about 70% consisting of either AAC, FLV, or MPEG-encoded videos.
By website optimization on 12 Aug 2011 PM