You have a beautifully produced, really cool video! You have spent many hours to create this work of art, and you are proud of it. As well you should be! Now you want to put it online for the entire world to enjoy… but you have questions. Will it look good? Will the playback be smooth or jerky? Will it have to be the size of a dime? These are all good questions, and we hope to help you by explaining some key elements of broadcast quality video on the Internet. Many Web sites offer the service but what does this mean for you and your company?

First, let us define broadcast quality, and more important, explain the data rate necessary to qualify as broadcast quality.

ITU-R 601 (Broadcast Quality) NTSC video has a pixel resolution of 720 x 486 and a frame rate of 29.97 frames per second (some people inaccurately use the term 30 frames per second). The other 0.03 frames per second are used for color information on a sub carrier frequency (3.58MHz). That’s how they put color into TV! Broadcast video is also made of chrominance (color) and luminance (brightness value from black to white). Broadcast video is expressed as 4:2:2 video (i.e. luminance: chrominance R: chrominance B video). The luminance value is twice the value of the each chrominance. Uncompressed video is expressed as 4:4:4 (its data rate is massive!) and DV cameras, like the ones you have at home, usually have 4:1:1 (much smaller data rate), where each chrominance value is one quarter of the total luminance value. This is important because the lower the chrominance value, the less color information contained in the video, which equates to lower quality video. The reason why DV camera manufacturers lower the chrominance instead of the luminance is because the human eye notices changes in black to white more easily than changes in color.

All of this technical video jargon might seem overwhelming, but hang in there, because it’s math time!

Here is an example: imagine one frame of uncompressed 4:4:4 video, 720 x 486 pixels, i.e. 349,920 bytes, times 3 (luminance, chrominance R, chrominance B) = 1,049,760 bytes per frame (approximately one megabyte per frame). Multiply this by 29.97 frames per second, and one second of video will consume 30 megabytes. Since Broadcast video is 4:2:2, it will consume 0.667 megabytes per frame and 20 megabytes per second (remember, 1 megabyte=1,024 kilobytes). Broadcast video’s data rate is huge, so imagine HD! Unfortunately for you and your video, your Internet connection does not support these speeds.

Internet speed
So now that you have your Broadcast video, you want to send it out over the Internet for all to enjoy. However, you have one large problem… Internet connection speed!
Assuming all the speed-hype, your cable modem should be between 4-7 megabits per second, and DSL can be up to 3 megabits per second (but between you and me, you’re happy when DSL reaches 1.2 megabits per second, and cable 3megabits per second). Those speeds translate to 0.5 – 0.875, and 0.375 megabytes per second, respectively. But your camcorder needs 3.6 megabytes per second, and broadcast quality needs 20 megabytes per second. Something (size, quality, buffer time) will suffer, but the good news is that you get to decide which one! By the way, most videos on the Internet are not 720×486 in size they are much smaller. So, let’s go there!

Internet Video Sizes
Apple’s current video iPod has a screen resolution of 320×240. The video looks great and your video could look great too! Let’s look at what would happen if you resized your video to 320×240 instead of 720×486. Assuming no compression, a 4:4:4 320×240 video will consume 6.585 megabytes per second, a significant drop in size from 30 MB’s. Under the same conditions a 4:2:2 video will consume 153,600 bytes per frame and 4.39MB per second, and a 4:1:1 video will be 115,200 bytes per frame and 3.29MB per second. Your video still contains too much data for current Internet speeds, but at least we are headed in the right direction. In this example, the only change you made was making your video smaller in size.

Buffer Time
No one likes to sit and watch a video stutter along on the Internet. Several factors can cause video stuttering, but bandwidth is usually the culprit. A 3.29MB per second video will stutter on almost all Internet connections. The remaining option and the most likely factor that will affect quality is compression. Compression can be accomplished in several ways, due to the number of variables involved, and unless you are familiar with the compression process, it is best to discuss this with your videographer /editor.

Bottom Line
• Broadcast quality video cannot be transferred on regular or broadband Internet connections.
• Something in your video will be sacrificed, usually video size, video quality or buffer time (or any combination thereof) to make it play on the Internet.
• To make your video look great on the Internet, you have to use compression and change the video size. And this is where VideoBloom can help you!