Originally posted by ChiefPam:
Help! I didn't do my trailer in WMM, I made it in Roxio's VideoWave. I managed to save it to an .avi file extension (it doesn't want to tell you what format it's using) but the resulting file is only 12MB instead of hundreds, so I'm thinking I'm doing something wrong... does anyone have any clue?
I guess I could try importing it into WMM... I worry about the quality degrading in the process. Legacy of too many forth-generation near-unwatchable video-tapes
PJ While I've never used Movie Maker, I do know a little about generic movie files. Files such as QuickTime, Real Video, WMV, and AVI are essentially shell file formats giving a common interface to the outside world. So a player that supports AVI, for instance, should be able to play any AVI file...
And here's the big IF...
if the correct codec (compression-decompression) is loaded. Within each shell format are potentially dozens of possible codecs that do the actual work of compressing a movie file into something small enough for people to handle and for decompressing a movie so that it can be played.
Installing QuickTime or Windows Media Player will normally supply the most commonly used codecs that work within the shell formats. One of the best codecs being used now is the H.264 codec based on MPEG-4, a far superior codec than the most common MPEG-2 formats and the most common Intel Indeo codec. But sometimes you'll run into a file that was created using a codec you don't have. Some players, like Real Player, will prompt you to download the appropriate codec. Or if it's really obscure, you may have to go hunting for it yourself.
As for your question of why your file was only 12MB while Sara's was initially much larger, that depends on what step in the process you're in at the time. When a video is a WIP, it's best to work with uncompressed video because as you make changes, the new video would have to be re-rendered (put into a format so that you can see it play). The more times something is rendered, the more it'll degrade since all major codecs are lossy compression methods (you lose a little bit of clarity each time), the most notable exception being the Apple Lossless Compression codec used in iTunes for audio files (within the Dolby AAC/.m4a shell format that iTMS uses). Try ripping a song off of a CD in 192kbps format and again using the Apple Lossless Codec. You'll find your average song is about 2-4MB in size with 192kbps but about 18-20MB in size with the lossless method. Yet both are AAC files.
So initially you work in an uncompressed format so that you don't lose anything until you're ready for the final product. When it's time to shrink the video, you choose your codec and your program will squish your video down to a manageable size.
Second, Sara is using DVI-quality, which is typically 720x480 resolution, much higher than most videos posted to the MB.
It may or may not surprise you but compression techniques are so good these days that uncompressed video may be an order of magnitude larger or even more. An H.264 codec can squeeze an hour of DVD-quality video into a mere 200MB file while the original video could be many gigabytes in size. That same video using the DVD-quality MPEG-2 codec would be 2-8GB in size. An MP3 (MPEG-1, Layer 3, not MPEG-3) file may be a sixth the size of its uncompressed original (in the Windows world, that's a .wav file).
If all that was too techy, the bottom line is that all AVI files are not made alike.