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Tuesday, December 14, 2010

The file is easier than the stream

In our LinkedIn discussion group, Robert Clark wrote:

"Probably the most underestimated and complex aspect of your capability is advertising insertion. In fact OTT Video/Internet TV providers are woefully behind the Pay-TV and Broadcast sectors who have developed advertising and digital program insertion capabilities over decades"

Robert is an experienced broadband, telecom, and video specialist. I feel fortunate to have him participating and I appreciate his comments. The answer to this issue lies in the difference between the way a TV set or a standard cable box handles video, and the way a computer handles video.

To a TV set or cable box, video comes through as a real-time stream. Whether it is an analog signal or a series of digital ones and zeros, it is the change in the signal over time that carries the information. To insert a targeted advertisement into a stream, you have to essentially switch from one stream of data, to a second stream, then switch back in real time. This is complicated in a system designed to carry one stream at a time.

For a computer, video is a file, a collection of data abstracted from real time. To the computer a video file is not so different from a word document or a spreadsheet. The video file can be easily cut, copied, pasted, and saved. This is much easier than with a real-time stream of information. Even “live” TV is not really live. With a computer PVR, the video signal is saved as a file to the hard drive, and the file from the hard drive is displayed to the TV. The delay may be only one second. This is what allows the magic of pausing live TV. The file reading is simply paused while the video signal continues to be written to the hard drive.

One interesting ramification is that advertising insertion can be implemented to a software package like Windows Media Center, without changing the media center software at all. If you have access to the saved video files on the local hard disc, ads can be edited into the files and Windows Media Center will play them as if they were originally recorded that way.

I am sure that I am oversimplifying, and hopefully our software experts here can correct me. I have read an acronym SMOP (Simply a Matter of Programming) when a concept sounds easy but takes many hours of work for someone to do it in a smooth and professional way.

Ad detection and flagging software is already available for current media center programs. I am most familiar with the open source mythcommflag program for MythTV. These programs use features like the brief presence of an all-black screen to signal the start of an advertising break. They are used to facilitate ad skipping and editing ads out. The same technology can be used to mark spots for interest-based ads to be edited in.

Robert is correct that ad insertion technology is a major challenge to satellite and cable MSOs. To a system based on a managed network of HTPCs, however, it should be relatively easy. It may be similar to the differenceibetween trying to alter a traditional film photograph compared to using photoshop programs on a digital picture file.

Because the same technology of file editing is used, advertising video files can be downloaded via the internet and inserted to addressable target files in the same way whether those video program files come from cable, satellite, or free over-the-air.


It does not require a large desktop computer. I am running Windows 7 Media Center on an Acer Aspire Revo r3610, which is about the size of a paperback book.

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