File compression is mainly for the birds...

tech explorer

tech explorer

New Member
in my case. Tried it on two files and I got a compression ranging from 3.4% to 3.6%. Not much and the original files are left inside the folders to be disposed of. Considering I have over 1,900 files, it's not worth that effort. I'd rather pick up a couple of 16GB SD memory cards for $22 (btw due to the original files remaining, unable to do a global compression as there's not enough space - the only positive thing I can say is I can readily open up those zipped files).
 
What are you trying to zip? Generally, it doesn't work on something that's already compressed, or on binary type data like audio or video. You jus tend up making it bigger.
 
Most (or probably all) of those are already compressed and recompressing them with zip or similar will likely make them bigger. You could re-encode them with lower quality to reduce the size but I doubt that's what you want.

To really see the difference, take a ~5MB mp3 and a ~5MB text file, generate the text file if you want, it's pretty trivial to write a vbs script to do it, and zip them both. You'll see a big difference in the compressed textfile size vs the mp3.
 
All of the files are downloaded off the internet.

I notice that when the files are the same size (in their runtime, e.g. 10 minutes), there can be dramatic differences in how many MB each file can be. So for two files that play for 10 minutes, one may be only 1MB and the other may be 10MB. I'm wondering whether compression is a factor? Also wondering whether one video file may be more graphics intensive than the other or maybe has more movement in its play than the other or even if the file format is a factor?
 
Naturally with lossy compression, the thing you've compressed makes a big difference. It also depends on what algorithm is used h264, divx/xvid, etc as well as the target bitrate - aka 'quality'.

A big part of video compression is only keeping the parts of a scene that have changed. So if a large portion of the frame stays the same, we can keep it from the 1st frame and all subsequent frames we just reference the initial. It will also reuse segments of previous and future frames to further reduce file size.

In short, lots of things are factors on the end file size.
 
I'll be checking the Android market for a better file compressor, i.e.:

1) one that removes the original file and
2) can compress the file even better

It's worthwhile not to put off compressing files. I've set up another system that's saving me GBs of space.
 
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