Compressing avi files

[somerandomguy]

Hi guys, first off I'll just say that I know very little about various compression techniques for video files.
That said, I need a way of compressing an avi files into a smaller format (mpeg2 or DivX?). I need to be able to do it with a shareware or freeware program, and I would prefer a loss less compression if possible. These movies are 700MB each, and they're really clogging up my hard drive.
Can anyone help me out with this?
Thanks in advance.

"Ignorance is bliss, but I tend to get screwed over."

 

[Guest]

I recomend TmpgEnc - <A HREF="http/www.tmpgenc.com" target="_new">www.tmpgenc.com</A> .
Good free program.

Intel / AMD - <A HREF="http/www.llnl.gov/asci/news/white_news.html" target="_new">IBM are still the best</A>

 

[lakedude]

Ok a 90 minute movie recorded in 16 by 9 format in full screen resolution at 720 by 384 will take up 720 * 384 pixels per frame * 24 bits per pixel * 29.97 frames per second * 60 seconds per minute * 90 minutes / 8bits per byte / 1024 bytes per kB /1024 kB per MB /1024 MB per GB = about 125GB for an uncompressed 90 minute video with no sound. Using lossless compression you could take that in half down to roughly 63GB. How many movies did you want to fit on your HD? One? Maybe we should think about going lossy? MJPEG is the easiest lossy format to understand. MJPEG is nothing more then a series of JPEG pictures so instead of each frame taking up 720*384*24/8/1024=810kB each frame will take up more like 81kB for a 10 to 1 compression rate and a final file size of about 12.5GB. Note that even at 12.5GB we have already lost something just as a Jpeg has loss over a bmp. Not small enough for you yet? Enter MPEG. Mpeg2 uses Jpeg pictures called key frames every so often but in between key frames it (basically) only stores the differences between one frame and the next. Using Mpeg2 compression is more lossy then Mjpeg but allows us to get your 90 minute movie down to 4 or 5 GB. The quality is still very good at this point but is far from perfect. Still not small enough? Enter Mpeg4. Mpeg4 works like Mpeg2 but is more advanced and uses motion prediction and other advanced features which I do not fully understand in order to make a 125GB movie fit on one 700MB cdr and now you want to make it smaller with no loss????? At 700MB about 100MBs is sound so the video part is going to be about 600MB meaning you have compressed the thing about 213 to 1 already.

It is possable to compress farther by resizing and lowering the quality but this will be far from lossless. Use Virtual Dub or Nandub available at: <A HREF="http/www.doom9.net" target="_new">http/www.doom9.net</A>

The AVI you already have is very likely NOT an <b>A</b>udio <b>V</b>ideo <b>I</b>nterlaced file. Something.avi is a container not a format and your movie something.avi is very likely already in some form of mpeg4/divx format.

Remember if you ain't Muslim you ain't Shiite.<P ID="edit"><FONT SIZE=-1><EM>Edited by lakedude on 01/17/02 05:46 PM.</EM></FONT></P>

 

[Guest]

Actually Uncompressd AVI 16:9 or 4:3 are both 720X480 for NTSC. the 19:6 just have a diferant pixel aspect ratio.
This will make is in real uncompressd area 42MB/Sec.

If you are talking about compressing files in DviX/Mpg4 more then they are, Unless you get a computer like the one in my signiture, Not in this space life time continum.
If you have some normal AVI files at 700MB and you want to make them small them my first link or a DivX compressing program will probably do.

Get a nice CD burner and burn the files to CDR.

Intel / AMD - <A HREF="http/www.llnl.gov/asci/news/white_news.html" target="_new">IBM are still the best</A>

 

[lakedude]

Have Scub and I confused you enough yet?

Is your something dot AVI an AVI file or a divx file in an AVI container? In other words are these 700MB files full lenght movies or 10 minute clips? If they are clips then either Scub or I can help you save a ton of space. If they are full lenght movies then the most you could save is about 2 to 1 and you will need to give up quality to do it.

Remember if you ain't Muslim you ain't Shiite.