Record and Save Streaming MediaSubmit to del.icio.us | digg it! | Submit to Slashdot
Sometimes when I watch or listen to something online, I want to save the content on my computer. Usually, it takes more skill than right clicking the link and selecting “save target.” This is because it is usually “streamed media.” Streamed media is different from downloaded media. In downloaded media, you can use your browser to save the media file using the “save target” method mentioned above. With streamed media, you need a program that can negotiate different protocols.
Browsers typically use a protocol called “HyperText Transport Protocol” or HTTP. Sometimes they can utilize the File Transfer Protocol or FTP. Downloaded media is transmitted in the Internet via these two protocols. However, streamed media uses proprietary protocols like MMS (Microsoft Media Services) and RTSP (Real Time Streaming Protocol) that are normally usable only by media players distributed by the creators of the respective protocols. This means that browsers like Netscape and Internet Explorer, which only use HTTP and FTP, cannot utilize MMS and RTSP. Those are reserved for RealPlayer and Windows Media Player. Even if you know the URL to the media file, you still cannot access it through a browser. For example, pretend that there is a media file at “art-app.com/media/ddr.asf.” If I allowed it on my server, anybody can download it via HTTP through “http://art-app.com/media/ddr.asf.” If I wanted it to be streamed media, I would only enable MMS or RTSP. So, anytime somebody typed “http://art-app.com/media/ddr.asf” in Internet Explorer, he or she would receive an error message. But, if someone entered “mms://art-app.com/media/ddr.asf” in Windows Media Player, the media would play.
Why do people do this? It hampers Internet users from copying the media and distributing it illegally. If you tried the example above in Windows Media Player, you would notice that you can only play, not save. Streamed media was designed to be played, not saved. Companies who publish the content go to great lengths to prevent copying the media. But, I always say, anything man-made is “hackable”
The companies who created the streaming protocols, also created libraries (programming interfaces) to access the protocols. People have taken those libraries and created their own programs to circumvent the streaming-only protection. To the server, the programs just look like media players. The “media players” actually take the streamed data and instead of outputting the content to the screen, they output the data to a file. Since the server thinks the programs are media players, it will only give files at the speed of content. For example, if it is a 50-second video, it will take 50 seconds to download it. The length of the content is synonymous with the length of the download.
So where are these programs? To save streaming media, I use one or more of the tools listed on this website. One that has worked really well for me (which is also on this list) is SDP. Try it! Comment on your experience with streamed media.
Posted on Tuesday, October 25th, 2005