The high compression in MPEG is achieved due to information loss.
However, you can translate MPEG-files to uncompressed AVI, but file will very large. Use VirtuaDub or other AVI editor. http/www.divx-digest.com/
Can U please advise me that how I can write my DAT file (video songs on my hard drive) to my CD Writer.I want to give that copy to my friend.I tried and even my RICOH Writer took almost 30 minutes for simulation and another 25 minutes for writing but at the end of the day, nothing happened to be written, at 2X speed,on the CD except a few data, which also is not readable.
AVI,DAT,MPG are formats of video files.
MPEG 1,2,4 - format of (de)coding (algorithm).
Quality of AVI (uncompressed from MPG) and MPG are the same. If you mean how much is data loss - it depends on format (MPEG 1,2,4) and bitrate.
It's worth adding to this that MPEGs (1, 2 and 4) as well as AVI, and in fact ANY other formats (there are so many, including Quicktimes MOV, Windows media etc etc) all use different compression algorithms and generally you will find programs to convert from one to another (such as FLASK to change MPEG2 into others). However, in terms of quality, ALL of them including native DV (usually the 'original' in terms of video editing) are compressed in one form or another (DV being i guess the least compressed). What counts in many ways is the bit-rate. You can make MPEG 1 with very very high bit rate that looks spectacular, but won't conform to a STANDARD (ie usually MPEG1 is for Video CD, which needs about 1150 kbits per second for the video element). So, what i'm saying here, is that AVI as such doesn't have any particualr quality in itself. That's like asking how fast does a car drive at. AVI can be very good (with high bit rate) or very poor (low bit rate). Converting from one format to another will also surely lose even more quality.
Hope this helps, and didn't sound TOO much like a sermon.
AVI is not really anything but a container somewhat like a file folder. AVIs can contain many different video formats including MPEG. What I'm saying is that even though a file may be named blabla.avi could still be an MPEG. The video files I make have an avi extention but I use the divx codec which was being called mpeg4 even though I guess it really isn't.
Also reguarding your question lets do some math. Video is often viewed at fairly low resoution by todays standards. Lets say we wanted to store 90 min of uncompressed video at 640 by 480. There are 640*480 pixels per frame *24 bits per pixel(at true color)*29.97 frames per second (NTSC)*60 seconds per minute *90 minutes for a grand total of about 1193 billion bits or 149 billion bytes needed to store only one uncompressed 90 minute movie. How big is your HD? I've got a 60G and a 30G that together could not store one uncompressed 90 minute movie. Compression is your friend.