Using movie maker . . .

[aviheader]

OK hi everyone. Just started using windows movie maker version 2002. A strange beast for sure - very intimidating. Many times I walked away from WMM but kept coming back and have finally gained mastery over it. The problem is that WMM is very picky with memory especially if you are using an old computer without any.

However i persevered and set up my virtual memory to 512MB and minimum hard drive space to 2 GB. There are things to watch for.

When you are transferring from camera to WMM dont use it's built in features too much. Use windows camera wizard to transfer AVi files from your (say) Canon Power shot to your hard drive. I tried to transfer files from camera to USB stick but the camera wizard prefers to use the hard drive. Thats ok. Once the files are on the hard drive then copy those files to a USB stick and then delete those same files from the hard drive freeing up hard drive space (hey i only got a 6 GB hard drive- ya really!!!)

Ok now comes the real challenge. When you are saving an edited movie (with AVI source files) The only setting that works in WMM is the DV-AVI format. All the rest of those settings that save files in different formats don't work if you are tight in the ram department because WMM is a memory HOG in those other formats.

So the DV-AVI hardly uses any memory at all - amazing but . . . . the file produced is 3 times larger than the source files. Thats OK as you tube accepts that format but . . . you will be filling up your archive USB sticks pretty fast

My question is why does the DV-AVI format in WMM bloat the files that way?

[jagabo]

DV doesn't compress very much and uses a fixed bitrate of about 25 Mb/s (about 13 GB/hr). It's also an intra-frame encoder -- meaning each frame of video is compressed using only information from that frame, much like a JPEG image. Conversely each frame can be decompressed using only the compressed data for that frame.

https://en.wikipedia.org/wiki/Intra-frame_coding

Most of the other codec compress much more and use inter-frame encoding. The compressed data for most frames only contains changes from a previous or later frame. For example, in a talking head shot maybe only the speaker's lips are moving, so only those moving lips are encoded, the rest of the frame is copied from another frame. This can reduce the amount of compressed data by a very large amount. But this means that all those other "reference" frames need to be in memory when the video is being compressed so the codec can compare to them. And it means many frames have to be in memory to decompress the video.

https://en.wikipedia.org/wiki/Inter_frame

[aviheader]

Ok your saying that DV-AVI format uses intraframe compression so the output file size should be smaller - but it is actually larger. If I shoot a 640 *480 vid then the DV -AVI format in WMM uses a 720 * 480 format. That does not explain the huge increase in output file size though. (some of it)

It is too bad that WMM has to bloat the files and there are no reasons for it. You can get good results with the native output from a canon powershot . . . but as soon as you edit video clips (add them together) then that forces a save in WMM in the DV-AVI format which is really stupid in my estimation. Hey MS why cant you write an movie editor using the canon format??

OH WMM IS NO LONGER SUPPORTED like most things Microsoft

[jagabo]

Ok your saying that DV-AVI format uses intraframe compression so the output file size should be smaller - but it is actually larger.

No, DV's 25 Mb/s is higher than most other codecs would use for 720x480, 29.97 fps video. Size is directly proportional to bitrate. In fact bitrate is defined as size/time (size usually in Kbits or Mbits, time in seconds).

[QUOTE=aviheader;2557586]If I shoot a 640 *480 vid then the DV -AVI format in WMM uses a 720 * 480 format.[/QOUTE]
DV supports only two frame sizes/rates: 720x480 at 29.97 fps, and 720x576 at 25 fps. DV was designed for 1995 era consumer grade computers.

That does not explain the huge increase in output file size though. (some of it)

The use of only intraframe encoding and the fixed bitrate explain it. Other codecs use much more advanced techniques (interframe as well as intraframe) and are more efficient (though usually slower).

It is too bad that WMM has to... bloat the files and there are no reasons for it. You can get good results with the native output from a canon powershot . . . but as soon as you edit video clips (add them together) then that forces a save in WMM in the DV-AVI format which is really stupid in my estimation. Hey MS why cant you write an movie editor using the canon format??

OH WMM IS NO LONGER SUPPORTED like most things Microsoft

WMM exists only to fill a checkbox filled in marketing brochures. "Windows provides a free video editor just like the Mac!"