remuxing mpg in Videoredo greatly reduces file size???

[Srivas]

Hi!

Just rendered a mpg stream in Vegas for DVD Architect, but the latter couldn't recognize the stream. So I did a plain remuxing in Videredo and as a result I got a working mpp file, but a few hundreds mb's less size!
First I couldn't believe that, I remuxed about 4,5 gb file and the result was around 4 gb, 500 mb less. I checked the file, everything is there, authored a dvd from it, it works like it should be. What happened?

I also tried to remux another mpg, a working one, and the same effect is there, more than 100 mb freed from one gb of data.

I know DVD Architect has a problem of showing proper file size, but Vegas is working ok, so what's the trick here?

Rendered files were originally avi files, captured VHS, rendered into mainconcept mpg files, Vegas Pro 11.

[mgh]

if the original was a .ts file- remuxing would reduce file size quite a bit

[Srivas]

ok, but what's the reason behind it?

[mgh]

containers have overhead, some more, some less. basically information not needed for a DVD to play smoothly, is being removed.
the ts format is for streaming video.

[jagabo]

TS files have a lot of overhead to make it easy for a player to pick up the video mid stream. That's why they're used for broadcast. For example, when you change the channel on the TV the TV can't go back to the beginning of the file to read the header information then seek to the desired frame. It just picks up the stream wherever it is in the broadcast. That means there needs to be a lot of redundant information in every GOP or frame.

[Srivas]

ok, that makes sense. What it has to do with the mainconcept mpg files? Could that be that Vegas keeps all the information in the GOPs, although a dvd is not a broadcast media? I mean, do I really need that if the file will be played back on a dvd player?

[jagabo]

When you make a DVD the MPEG 2 data will be remuxed into a VOB container.

[Srivas]

ok, I figured it out. Yes you're right, I tested it out, the size will be the same, whether I remux it through videoredo or dvd architect.