DVD Data Size Miscalculation Problem.

[jungleexplorer]

I have been using VS for over 12 years to produce DVD videos. I have used many versions and am now currently using VS Pro X4. When I when I render a VSP to a DVD I always render to an ISO file and then use that ISO file to burn DVDs. I have always noticed a data size discrepancy between what VS predicts the final data size of the DVD will be and actually what it turns out to be. In most earlier versions of VS this size discrepancy has always been small (maybe a few hundred megabytes), but in X4 it is huge, as much as 2 Gigabytes for a full length DVD. The problem I am having is that I know that a two hour DVD quality video will fit on a single layer 4.7 GB DVD disc, but VS is projecting it to be 7 GB. Now in former versions of VS I could go ahead and render the project to an ISO file knowing that the final product would fit on a 4.7 DVD. But X4 will not allow me to do that. When I try to do this in X4, it comes up and says that the project is too large to fit on a 4.7 and to click OK to use DVD FIT or click cancel to go back and edit the video. If I click on OK, then VS reduces the quality of the video to fit a 4.7 DVD. The problem is that the final product turns out being around 3 GB. This means I have lost about 1.5 GB in video quality.

This is really irritating! How do I fix this?

[Ken Berry]

I know that a two hour DVD quality video will fit on a single layer 4.7 GB DVD disc

The problem with that statement is that if by 'DVD quality' you mean very good quality, then that is not the case. Yes, commercially made DVDs produce great quality videos of that length, but they are produced by a different method -- pressing -- and after multiple passes to ensure highest quality; while home-burned DVDs use a burning laser and only two pass rrendering. At best the quality of a two hour single layer DVD burned at home will be more like a VHS tape. In other words, it will be quite watchable -- though might be a bit grainy and/or pixellated on a larger HDTV screen.

I suspect also that the differential in predicted file size might come from using a vsp in the burning timeline, rather than an actual DVD-compatible mpeg-2. Conversion of that vsp to mpeg-2 will have to take place as part of the burning process, and unless you change it, it will use the default properties set out in the Options cogwheel icon in the bottom left of the burning screen. So you could also change those properties down to a bitrate of around 4000 to 4500 kbps to get a file which would fit on a single layer DVD.

I have to confess, though, that what I do in a similar circumstance is set the output disc size at 8.5 GB (i.e. dual layer), and produce a DVD folder at the end rather than burn a disc. An ISO is much the same, of course. Then I use DVD Shrink to reduce that folder down to single disc layer size as I think Shrink does a far better job than VS's own fit to disc facility. If you have Nero, you could also use its Recode utility (much the same as they guy who runs Recode for Nero was the originator of Shrink!)

[jungleexplorer]

Hi Ken. I am fully aware about the difference of between Holly produced DVDs and home produced DVDs . As I said to begin with, I have been producing dvds for over 12 years. My question was not about the difference between the quality of Hollywood 2 hour dvd and a home made dvd made on VS and recorded on a DVD writable media. My question was strictly about the huge data size discrepancy between what VS calculates the final product will be and what it actually turns out to be. I have fit many 2 hour dvds on to DVD-R 4.7 GB media with excellent result and very good quality. I am not saying they were Hollywood quality, but the were better then any VHS I have ever seen.

The problem is not fitting a 2 hour video on a 4.7 GB DVD-R. The problem is that X4 miscalculates that the project will not fit, reduces the quality of the project way down so it will fit and produces as really low quality end product that is 1.5 GB smaller then what will fit on a 4.7 GB DVD-R. In earlier version of VS, I could go ahead and render the project at full quality, (even though VS was telling me that it would not fit) because I knew that VS was miscalculating the final data size and that the final product would fit. X4 will not allow me to do this.

What I need to know is this. Is there a setting in X4 that I can use to stop it from forcing the use of DVD Fit, or a fix that will improve VS ability to correctly calculate the data size of the final product, or some other way to correct this. Is Corel aware of this problem? Do they have to fix for it or are they just going to continue to release new versions ever few months that offer new features that don't work and never fix the long standing problems. I am so tired of buying a new car to fix a flat tire only to find out that the new car has the same flat tire.