MPG and AVI files - quality

[Geff]

I have created a 15 second intro for my movies using Sony Vegas MS. I have now rendered the file to use it in future projects which will be created in SVMS and then create a DVD with DVD Architect.

Which is the best format to use to render the file? I have tried the obvious three with quite different file sizes - do I assume the largest (AVI) is the best and if so will there be any discernable difference in picture quality if I use MPG1 or MPG2?

Size of files AVI 75.2MB - MPG1 4.79MB - MPG2 9.42MB (15 seconds)

To create the intro I copied a VOB file from a DVD and changed the file extension to MPG before importing it into SVMS for editing. How does this relate to the MPG1 and MPG2 formats?

Could someone please explain the difference in these formats?

 

[redsox_mark]

DVDs (standard definition ones) use MPEG2. So if this is an introduction video which will be used in DVD (and not be changed), then it is best to render to MPEG2 - then DVDA won't need to re-compress it.

AVI is a wrapper which can contain many types of format, including DV. If you were say creating a background motion menu, then I would use DV-avi, as DVDA would need to recompress it anyway (when you add text and buttons).

You don't want to use MPEG1, that is lower quality and would still need to be recompressed.

Your .VOB files would have contained MPEG2.

 

[senu]

Just to add to Marks post

1) forget mpeg1

2) DV AVI gives the best PQ but is large ( 1hr = 13Gb) vs 1 hr of Mpeg2 which at best PQ =4.7Gb

3) Mpeg2 is very cleverly compressed as it is comparable in PQ to DV AVI if well encoded but much smaller file size: It is just not as easy to edit without PQ loss hence it being better to start out as DV AVI

At any rate that is what DVDs contain so your AVI will get to be encoded to mpeg2 eventually
The VOB is an mpeg2 file which is of DVD standard having been "multiplexed" with audio which can be PCM ( like CD audio), AC3 ( Dolby digital ( Which MS cannot do) or mpeg audio as such I imagine you really dont need to rename it to mpeg for use within Vegas as the software will import it as such.

If you do already have an mpeg2 file ( for your intro) try and resist rendering it back to AVI as it will still need to be compressed to mpeg2 by DVDA and these multiple encodings will result in time use with potential PQ loss

Off topic : What Mark means by AVI being a wrapper is that: Not all AVI is DV quality as having the AVI extension doesnt not tell you how a video file got encoded . As such the Divx ,Xvid ( mpeg4) mjpeg) which also have AVI extensions, are usually smaller than mpeg2 and not really comparable in absolute PQ to DV AVi

 

[twoodley]

I have created a 15 second intro for my movies using Sony Vegas MS. I have now rendered the file to use it in future projects which will be created in SVMS and then create a DVD with DVD Architect.

Why render it at all??
If you are going to use this intro on future projects just save the intro as a Vegas project in its own right (call it Intro). When you want to make a new project, open "Intro" and 'Save As' "New Project". You now have the intro in the new project at the original quality, and it is editable, especially if you have added Titles.

 

[redsox_mark]

I guess it depends what is meant by "intro". If this is for example a "first play" video which you want to use unchanged for each DVD, then rendering it to MPEG2 makes sense - render it once, and use it many times. If it is part of something larger and you want to make changes each time, then you could do what twoodley suggests.

 

[Geff]

Why render it at all??

Without rendering it I believe I would have to keep the original source file which is 1GB. If I render I can delete this.
I think I've got that right???

Thanks for all you help and advice and for explaing the different formats.

 

[redsox_mark]

Without rendering it I believe I would have to keep the original source file which is 1GB. If I render I can delete this.
I think I've got that right???

Yes that is correct.

 

[mmace]

I did this for my DVD's, I made myself a nice intro, spent ages on it and made it look professional, I now regret not keeping the original as I am now moving on to creating Blu-Ray movies and need my intor in Hi-Def which would have been easy before as all the parts to it were created in illustrator and were scalable!

I would create your intro in Hi-Def resolution and then create 2 files, one in MPEG2 1920x1080 and another at 720x576 16:9
always best to future proof yourself, you may not be thinking about it now, but when HD-DVD and Blu-Ray burners drop to prices like DVD is then you'll probably buy one!

 

[redsox_mark]

Maff - that is good advice if one is creating an intro from scalable assets. In Geff's case though his intro is made from a standard def DVD source, so he can't improve on that.