Computer Hope

Software => Computer software => Topic started by: Redcaa on January 08, 2011, 05:32:24 PM

Title: WinRAR compression?
Post by: Redcaa on January 08, 2011, 05:32:24 PM

I compressed a 500mb file in winRAR, maximum compression level, took 5mins, when the bar went to 100 (right that moment the rar size was roughly 103mb) it stayed for a few seconds and the file size dramatically began to increase! All the way back up to 500mb =.=

Before I spent 30mins compressing 4 files to find out it literally did nothing =.=

So why does this happen? Help. :D

Title: Re: WinRAR compression?
Post by: kpac on January 08, 2011, 05:37:20 PM

Compressing one single file won't really lower the file size at all. You'll only see results when compressing multiple files.

Title: Re: WinRAR compression?
Post by: Redcaa on January 08, 2011, 06:02:21 PM

Well, before when I compressed the 4 files, open the RAR and looked at the compression ratio, the 500mb file (yes I compressed that file with 3 other files initially) was at 0%.

So it seems (I might be wrong) that the file just isn't compress-ing. Oh, and it's a video. Divx format.

Title: Re: WinRAR compression?
Post by: Geek-9pm on January 08, 2011, 11:10:04 PM

Many video formats already are high compression.
http://en.wikipedia.org/wiki/Video_compression

Title: Re: WinRAR compression?
Post by: BC_Programmer on January 09, 2011, 11:05:53 AM

Quote from: kpac on January 08, 2011, 05:37:20 PM

Compressing one single file won't really lower the file size at all. You'll only see results when compressing multiple files.

Wrong.

Title: Re: WinRAR compression?
Post by: BC_Programmer on January 09, 2011, 11:06:37 AM

Quote from: Redcaa on January 08, 2011, 06:02:21 PM

So it seems (I might be wrong) that the file just isn't compress-ing. Oh, and it's a video. Divx format.

As geek says- the file is already compressed. (via DivX, in your case)

Edit: oops, these were supposed to be the same post...

Title: Re: WinRAR compression?
Post by: Redcaa on January 09, 2011, 01:55:16 PM

Ahhh, so is it possible to decrease the size anymore?
I don't want to compress it in to any other format because of the risk to it's quality.

Cheeers :D

Title: Re: WinRAR compression?
Post by: Geek-9pm on January 09, 2011, 04:13:47 PM

Read the link I gave.
You can do any of these:
1.Reduce the resolutions size. Forget HDTV.
2. Change the frame rate, 20fps is passable.
3. Make it shorter, remove boring sequences.
4. Serve your guests abundant drinks and dim the lights.
As the article explains, the compression in video depends on how we humans see things.