Mixing 4/3 and 16/9 footage and other, using DVDA

[Phil Gosselin]

Hi all,

Very soon I will need to create a dvd with a mixture of videos, some we shot and some that were shot 5 years ago.

Ours are of HDV sources downgraded to DVD resolution and the others are 720x480 widescreened.

How could I go into DVDA to make such a project. As I understand you can only set a project to be in either 16/9 or 4/3.

Will it automatically detect the differences and apply settings accordingly or...

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My other concern is related to bitrate. Since I will have either 12 or 8 videos per DVD they will have to be compressed to fit into the DVD.

Is it wiser to encode out of Vegas with a medium bitrate so that DVDA won't have to reencode them again OR render at full quality out of Vegas and let DVDA do it's thing?


Thanks

Philippe

[Seth Bloombaum]

Originally Posted by Phil Gosselin

...Very soon I will need to create a dvd with a mixture of videos, ... of HDV sources downgraded to DVD resolution and the others are 720x480 widescreened.

How could I go into DVDA to make such a project. As I understand you can only set a project to be in either 16/9 or 4/3.

None of these are 4/3 sources? Or, put another way, when you are done with your project, everything you've listed will be 720x480 widescreened. That's the only proper way to get 16/9 material on DVD.

...My other concern is related to bitrate. Since I will have either 12 or 8 videos per DVD they will have to be compressed to fit into the DVD.

Is it wiser to encode out of Vegas with a medium bitrate so that DVDA won't have to reencode them again OR render at full quality out of Vegas and let DVDA do it's thing?

Everything is compressed to fit on a DVD, since the maximum working video bitrate of apx. 8Mbps is about 1/3 the bitrate of DV or HDV.

Letting DVDA do the compression is the easiest, but with experienced hands somewhate better quality can be had rendering out of Vegas. Mistakes made with Vegas rendering can lead to *very* poor results - if the bitrate is too high, if it is the wrong format, or, if DVDA doesn't think it will fit on the disk, DVDA rerenders.

The basic rules of thumb for Vegas DVD renders are:
*Use AC-3 audio encoding (a separate but quick rendering pass in Vegas).
*Use the Mainconcept MPEG2 for DVDA template. Adjust parameters by clicking "Custom"
*Use variable bitrate (VBR) encoding with max 8Mbps for up to 70 minutes of material.
*Use a bitrate calculator or chart for total video lengths over 70 minutes. Most people consider 90 minutes to be the max for mixed content, but 2 hours or more is possible with low-motion content.

Edward Troxel's excellent newsletters are a wonderful source of Vegas info. Though some of the basic stuff was written for earlier versions, not much has changed.

And get thee to the Vegas forum! Most DVDA questions seem to be over there, not over here...

[Phil Gosselin]

These are pretty good pointers, thanks Seth!

I guess I will have to play around with the settings before I get the results I need. I now have 18 videos to fit on the DVD but I am sure they will end up with a 2-2.5 mgb bitrate which more than adequate.

Concerning the first question I think I saw a problem when there was none, all materials are widescreened so it doesn't really matter of the source resolution is not the same, I won't have to crop anything.

Cheers,

Philippe

[Randall Leong]

Originally Posted by Phil Gosselin

These are pretty good pointers, thanks Seth!

I guess I will have to play around with the settings before I get the results I need. I now have 18 videos to fit on the DVD but I am sure they will end up with a 2-2.5 mgb bitrate which more than adequate.

Concerning the first question I think I saw a problem when there was none, all materials are widescreened so it doesn't really matter of the source resolution is not the same, I won't have to crop anything.

Cheers,

Philippe

Phil,

What Seth told you is a good starting point. But in newer versions of Vegas, by default 4:3 video is pillarboxed (black borders on the sides of the image) if rendered in a 16:9 project. Likewise, 16:9 video by default is letterboxed (black borders on top and bottom) in a 4:3 project. You can tell the renderer to stretch such 4:3 video to fill the entire 16:9 frame (or "squeeze" 16:9 video to fit a 4:3 frame) if you desire.

And DVDA allows you to mix 4:3 and 16:9 rendered videos onto the same disc as long as they are in separate movies. The aspect ratio in the DVDA project should be set to 16:9 since you want the menus to be displayed correctly on a widescreen TV set (the menus will be letterboxed when the authored DVD is played back on a DVD player that had been configured to output in 4:3). Otherwise, if your DVDA project's aspect ratio is left at its default 4:3, the menus will also be in 4:3 (which will be either stretched or pillarboxed on a 16:9 set, depending on the set's settings).

As for the rendered video bitrate (as set in the Vegas' MainConcept MPEG-2 Encoder), there are separate values to set for maximum video bitrate, average video bitrate and minimum video bitrate. For the best compromise between image quality and compatibility with standalone DVD players, the average bitrate should be set no higher than 7 Mbps if using VBR (with the maximum bitrate set no higher than 8 Mbps). Otherwise, if the maximum bitrate is equal to or very close to the selected average bitrate, you might as well use CBR at the selected bitrate.