Is there any point???

[wuzzbert]

Hi,

I am converting some .avi files so I can put them onto DVD media to watch on my stand alone DVD player. I'm using TMPGEnc to convert the files to MPEG2 format.

The thing I don't understand is that when I use the wizzard to convert the file which is 1.3gb large it suggests I convert the file to 4.3gb.

What I can't understand is, what is the point of making a smaller file into a much larger one. It's not going to improve the quality so why do it. Can I just reduce the size down to 1.3gb on the wizzard and convert much quicker without loosing any quality, or does it not work like that.

Please can someone explain!!

[guns1inger]

I am assuming that your AVI file is compressed using the Divx or Xvid codec, or something similar. Different codecs use different algorythms to compress the video. Each has it's compromised and advantages. Some are fast to encode, but have poor image quality when played back. Others encode very slowly, but have a higher quality. Some are lossless, which means the data, when played back, is the same as the original. Some are lossy, and throw away information that it thinks you won't notice. The more you compress it, the more you will notice the missing data. Divx and Mpeg-2 are both lossy compression formats, however the use different algorythms to compress. Divx/Xvid are based around mpeg-4, which compresses better than mpeg-2 in many ways. The problem you have is that mpeg-2 is the standard for DVD, although some players can playback Divx/Xvid if it is encoded correctly. Assuming yours is just a normal DVD player, you need to got to mpeg-2, and the bigger the file, the better the picture quality (gross over-simplification, but in this case it will do).

If you want more infor, google for the technology and technical explanations regarding video compression.

[mats.hogberg]

No, it doesn't work like that. The regular AVI compression methods (DivX, XviD and other mpeg4 types) are much more efficient than mpeg2, so as a general rule of thumb, about 4* the AVI bitrate is needed to make it justice, when reencoding to mpeg2.
When (re)encoding, only 2 parameters define the size of the output: The length (in time) of the source and the bitrate used when (re)encoding. There is no correlation between source file size and output file size.
Since I guess you don't want to cut parts of the movie, you can only toy with different bitrates to come up with different output file sizes. Lower bitrate==lower quality.
Also, the encoding time is not related to the bitrate used, so encoding at a lower bitrate will not speed up the process.

/Mats