Definition: Bandwidth is how much data you can move in a given amount of time.

Real-world: If your streaming media is too big for the connection of a viewer, they see choppy and incomplete playback.

The file-to-bandwidth ratio is important when you get into developing streaming media. So before beginning to develop streaming media, a bandwidth strategy is needed (or at least understood). The goal is to provide the quality needed, work with the viewers connection speed and not overload your hardware (the server).

1. The Bandwidth Math Numbers
The problem with “bandwidth math” is that two different sets of numbers are used. There is one for data transmission (Kbps) and another for data storage (KB ).

Files are measured in “KB” – kilobytes
Bandwidth is measured in “Kbps” – kilobits per second

Note that files use kiloBYTES and bandwidth uses kiloBITS (note one is “byte” and the other “bit”). Here is the trick – there are 8 bits in a byte. So when we have a 2MB streaming media file we are not transferring the 2,048KB (1MB = 1,024KB ), we are transferring 8x’s that much (2,048KB x 8 bits = 16,384Kbps).

2. Estimating Monthly Bandwidth:
This formula makes sure you stay within your hosting plans bandwidth allotment (usually hosting plans give bandwidth in GB per month – go over this amount and you risk additional charges or termination of your account). Here’s the formula:

(Average Daily Visitors x Average # Views x Average Media Size (in KB )) x 31 days x 1.5 (this is the “guesstimate” factor that gives a 50% buffer)

As example:
(40 daily visitors x 60 views x 20,480 KB (= 20 MB ) average media size) x 31 days x 1.5 = 2,285,568,000 KB
2,285,568,000 KB / 1,024 (1 MB ) = 2,232,000 MB, which is approx. 2 GB of bandwidth per month.

– Troy @ TLC