File Compression

[SimsDiva]

A friend of mine is having problems with file compression, so I thought I'd tell you all the situation and see if someone can help me out with it.  Lord knows that people in the Sims community have become masters at crunching down big files!   

So here's the situation:  She's got a file that approximately 19 MB, and would like to compress it as much as possible so she can either email it to some friends, or upload it to a yahoo group we're all on.  Yahoo has a 5mb limit (as I'm sure most of you know).

I've downloaded many things for my game where the zip knocked down to a 1/3 of it's original size... so I know there's some way to super compress them.  Problem is, I can't figure out how to do it.  The most I've ever knocked one down is maybe a meg, if I was lucky.

Can someone tell me (in very easy terms) how to do some serious compressing on file size?  I was planning to RTFM (again) for both winzip/rar after I got some sleep, but I figured it might be a good idea to ask those who have mastered the process as well. 

I'd appreciate any pointers... this thing is driving me and my friend up the damn wall!

[eevilcat]

It depends on what kind of file your trying to compress. 19Mb is fairly large so it's probably a picture, a document containing picture(s) or a video clip. While your file compression software will reduce the size a bit it's certainly not going to knock it below 5Mb. What she needs to do is compress/change the format of the original file using appropriate software e.g. if it's a picture check the resolution (pixel size) and the format e.g. if it's in bitmap (.BMP) format then convert it to JPG and lower the quality. I don't know that much about video formats other than changing resolution and/or the compression codec can reduce the size e.g. DivX usually results in smaller files.

[Gwill]

Some types of files simply compress better than others.  Some types of files are already compressed by the very nature of their file format.
RAR compresses tighter than ZIP, and there are other formats that compress even more, but then people start complaining along the lines of "ONG I need Zip, my computer don't do RAR!"

[J. M. Pescado]

There is also the option of breaking it up into 3-4 zips as a multi-part file.

[jrd]

There's some good advice here.

Always start with the uncompressed source data, and make sure it is as small as possible. For images, this means turning it into JPG for lossy compression or PNG otherwise, compressing it as much as possible (PNG should always be compressed with the highest factor, and for JPG you often can go down to 70% without noticable quality loss), and make sure no extraneous data is included (you seldom-if-ever need thumbnails etc.).
Then compress with the highest compression factor. When I seriously need to crunch data I use 7Zip, solid archive, maximum compression. Experiment a bit with the values: e.g. Deflate64 for ZIP /may/ result in a smaller file, and /some/ 7Z archives can benefit from PPMd.
And if all else fails, span it across multiple archives.

[akatonbo]

Also, since there is a pretty good chance that a file which is now 19MB will never be squished down to under 5MB, your friend might want to start looking into other ways to share it besides email or the Yahoo group, such as uploading to one of the umpteen million free filesharing sites now available (MegaUpload being one, I wouldn't dream of trying to list them all) and then sending an email or a message to the Yahoo group notifying people about how they can download it.

[SimsDiva]

I'm sorry, I didn't notice I never said what type of file it was... crap!  (Serves me right for staying up all night simming.  Sheesh)  She's trying to compress a 15 minute mp3 into a send-able size. 

I'll ask her if she's able to split it up into smaller parts... not sure if she has the means to do it or not, but that would be a good solution to the problem.

If not, I'll point her towards megaupload or something similar.   

I appreciate the help!

[nekonoai]

tell her to get winrar. it allows for the splitting of files into chunks of any size.

[SimsDiva]

Some types of files simply compress better than others.  Some types of files are already compressed by the very nature of their file format.
RAR compresses tighter than ZIP, and there are other formats that compress even more, but then people start complaining along the lines of "ONG I need Zip, my computer don't do RAR!"

(Slightly OT)

You know, I was wary of using winrar at first, because I typically hate all unknown programs.  But once I figured out how much easier it was to use compared to winzip, I wished I'd heard of it long ago.  It's SO much easier and less time consuming.  Winzip is tedious when you have multiple files to open up.

[SimsDiva]

tell her to get winrar. it allows for the splitting of files into chunks of any size.

Oh, that's right, it does!  I remember seeing that option earlier when I was looking at it, now that you mentioned it.  I'll pass that on to her.   

*presses thanks button a few times for good measure*

[notveryawesome]

You can also change the quality-level of an MP3 file. If it's saved as CD quality, you can re-save it as radio quality, without affecting the sound much. I think you can do this through any standard media-player software.

[Rose Outlaw]

If it's saved as CD quality, you can re-save it as radio quality, without affecting the sound much.

Sorry to disagree, I think you notice the difference pretty well, at least in terms of music. Speaking in kb/s, 128 kb/s should be the absolute minimum unless it will be played on crappy devices with poor earphones/speakers.
If it's only audio like a plain audio book, podcast or play, lower rates are acceptable.

[Gwill]

How much quality an audio file needs depends entirely on what kind of sound it is, and what you want it for.
If it's music, and music you want to hear again and again, I agree 128 kb/s is the minimum.  If it's plain speech and you just need to hear what's being said, you can go much lower.  If you go too low it will sound like it's being read by Stephen Hawkins over a continental phone line, but it can still do the job.

[SimsDiva]

If it's saved as CD quality, you can re-save it as radio quality, without affecting the sound much.

Sorry to disagree, I think you notice the difference pretty well, at least in terms of music. Speaking in kb/s, 128 kb/s should be the absolute minimum unless it will be played on crappy devices with poor earphones/speakers.
If it's only audio like a plain audio book, podcast or play, lower rates are acceptable.

It's an interview, no music.

That was my original suggestion to her, when I helped her figure out how to go about saving it as an mp3.  The lowest setting on her WMP was 128 Kbps, and she didn't seem too keen on downloading Real Player.  I'm still trying to talk her into doing that.  It would be a lot less trouble for her to just do that, in the end.  Not to mention, it would be a quicker download for everyone if the size got whacked pretty good.

[Rose Outlaw]

Stupid WMP, stupid Real Player... talk your friend into getting CDex or something alike.