Streaming fundamentals

Content in this category discusses the basics of streaming video and related technology.

What's the right keyframe interval?

Interesting post came from the StreamingMedia Advanced list today: Question:  Anyone have any advise on key frame placement in h264 flash? I felt like I should know the answer to this, so I pulled together the following: Answer: Interesting question...

Streaming Video Capture Tools

Streaming producers don’t work in a vacuum, and one of the best ways to understand the best practices of other publishers on the web is to download and analyze the streaming files that they produce. I capture streaming videos a lot, exclusively to analyze the video files for research purposes. I use two primary tools to accomplish this, DownloadHelper (, which is available exclusively as a FireFox plug-in, and RealPlayer (, which works with any browser.This short article discusses these tools and features.

According to IDC, 94% of consumers can play streams of 1200 or higher

I was reading through some material on Adobe's web site (specifically, here) and noticed the following table, which I've copied verbatim, along with the explanatory note. Citing an August, 2008 IDC study that's referenced below, the table states that 94% of all consumers polled by IDC had downstream bandwidth sufficient to retrieve and play a streaming video file produced at 1200 kbps. In addition, 69% of all viewers could retrieve a 2400 kbps file.

I figured it was worth a post, because most sites that I've reviewed are producing at much lower bitrates than even 1200 kbps. If you haven't reviewed your streaming parameters recently, perhaps these stats wil provide some motivation. As they say, either go big, or don't go at all.

Video size types Video size 4:3 aspect size 16:9 aspect size Total bit rate (Kbps) Video bit rate (Kbps) Audio bit rate (Kbps) % US broadband consumers*
QCIF 176×144 144×108 192×144 192×108 256×144 48
16 (mono)
16 (mono)
Modem and ISDN
CIF 352×288 288×216 320×240 384×216
32 (stereo)
128 (stereo)
Low-end DSL
D1 720×486 640×480
128 (stereo)
128 (stereo)
Faster DSL
HD 1280×720
128 (stereo)
128 (stereo)
Cable modems

* Note: Based on the IDC 2008 Consumer Panel Broadband Survey. Each figure represents the percentage of users who have the bandwidth to support the respective total bit rate in that category. For example, 25% of users have bandwidth of at least 1200 Kbps to support the D1 video type but don't have the higher bandwidth needed to support the next higher bit rate of 1800 Kbps.

Online video viewing numbers "vastly" overstated

We like to drink our own Kool-Aid in the streaming video business, and most of us tended to accept the increasingly hyperbolic streaming video viewing numbers as fact. Well, Nielson funded a research study to the tune of $3.5 million that actually observed subjects through the course of their days and timed the various video-related activities (rather than simply accepting user surveys as fact).

Guess what? Most of us are still tied to the TV set. My take? I'll keep my head in the sand and assume that most casual uses of streaming video, like YouTube and the like, are vastly over-reported, while actual business uses, the kind that my readers and clients tend to produce, are right on track. I'm probably deluding myself, but it's early in the day, my to do list is free from check marks, and it's the only way I'll get it all done. Denial is not just a river in Egypt.

Here's the first graph from the article I read in Online Media Daily, with the URL below for the complete story.
The amount of time Americans spend watching online video is vastly overstated, according to the findings of some highly regarded research made public Tuesday. The disclosure, which is likely one of the more controversial findings being mined from an ambitious piece of academic research that actually observed how people spend their time consuming media, was made during one of a series of so-called "collaborative alliance" meetings hosted by Havas media shop MPG for the advertising and media industry in New York.

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Download free streaming media primer here

Note: The information on this page has been superceded by a Streaming Primer you can download here is pleased to offer for free download a streaming media primer written by Jan Ozer.

The primer starts by defining commonly used streaming terms like bandwidth, streaming and data rate, and then explains universal encoding parameters like VBR and I, B and P-frames. Then it introduces readers to the big three codecs, H.264, VP6 and VC-1, and briefly compares and contrasts Flash and Silverlight. The primer finishes with a section on how to choose common encoding parameters like data rate and resolution.

The primer is an amalgam of materials already available on, along with new content, in a compact, more convenient form for downloading, printing and sharing. The primer is freely downloadable and fully printable.


Streaming 103: Choosing Your Streaming Configuration Parameters

Though uniqueness is always a goal, it's always helpful to check what your competitors are doing before choosing streaming encoding parameters. The tables in this article make it a snap by detailing codec usage, resolution, data rate, and frame rate. for many of the top sites on the Internet.

Streaming 102: Codecs, plus VBR and CBR, and I, B an P Frames

This article defines codecs and streaming architectures, and then common encoding parameters like constant and variable bit rate encoding, and settings relating to I, B and P frames.

I, B and P-Frames (oh My!).

Streaming 101: The Basics - Codecs, Bandwidth, Data Rate and Resolution

Though many of us use streaming-related terms like data rate and bandwidth every day, there may be some residual lack of certainty as to what they precisely mean and why they are important. For this reason, in this introductory article on streaming media concepts, I define file related terms like bandwidth, frame rate, data rate and resolution, and then delivery options like streaming and progressive download