Problems with size in Nero

[donkey]

I just went into Nero to burn my mpg to svcd. After dragging the mpg file over to be burnt, it comes out as 725MB on the status bar and won't let me burn it onto a 700MB cd. I know that common sense.

How come this has happened for this mpg. I've burnt some others that were longer minutes wise and they fit. How come this one didn't and its there anyway to get the size down at all.

The file is 857,714,032.

Thanks

[donkey]

Some notes.

The file as an .avi is 716,166

I used virtual dub to extract the audio and used this in tmpg. Could that be making it larger.

The file as an mpg is in the message above.