Movie files can be very large. Some movies are compressed, to make the files smaller, but as a result the pictures are less detailed and probably even blurry.
This discussion is specifically intended for certain movies that link to this page, but some of this information can apply to any movie you download from the Internet.
Most computer displays sold in the last few years can support at least 1024 by 768 pixels. Usually the higher the resolution (the more pixels) the better, but a full color 1024x768 screen displays more than 3 megabytes of information. If you are viewing a movie at 30 frames per second, and each frame is 3 megabytes, that's 90 megabytes a second or more than 5 gigabytes per minute. That can put quite a strain on your network connection, hard disk, and even many of the latest graphics cards.
Compression methods have been developed to address these problems. People frequently focus on the primary item of interest in a scene, while the rest of the picture is mostly for context. Also, the item of interest often moves slowly or changes only a little bit from one instant to another. Compression techniques, then, can discard details about some portions of the picture, or things that change rapidly from one frame to the next, and if you're just passively watching a TV program you might not even notice.
| Compressed MPG Format | QuickTime MOV Format |
|---|---|
|
|
|
Unfortunately, as the above comparison shows, the compression used in the MPG format can result in a lot of lost detail that may be important in educational or analytical settings. QuickTime movies, on the other hand, can be made with little to no compression, resulting in a much clearer image at the cost of (sometimes significantly) larger files.
Download a small thumbnail movie first and preview it. If it seems like the content might be useful for your purpose, download the uncompressed QuickTime MOV version in the largest pixel resolution your display, free disk space, network connection etc. will allow.
When choosing your pixel resolution, check your player to see if it will let you view the movie full screen (and still have control over pause, frame forward and back, etc.) or whether only part of the screen is usable. There's no point downloading a movie larger than you can view. So for example if your monitor or projector is 1024x768, but you can't use the whole screen for some reason, consider downloading the 800x600 version instead.
Don't just click on the link to the movie. Instead, in most browsers you can right-click on the link and save the movie file to your hard disk. This will make it easier to monitor the progress of the download, and you can view it more than once, or test it with different viewers, without downloading it again.
Even if Windows is your favorite operating system, I strongly recommend QuickTime Player over Windows Media Player. As of the time this was written:
|
|
|