Why does my 7.6GB video turn into 9.5GB?

[JJDVS]

I set up a video for a dual-layer DVD.  Toast 17 says 7.6GB used and about 300MB still available.  When creating a disc image, it turns out to be over 9GB.  It won't burn directly to a disc either because of the size.  Why is toast off the mark?

[JJDVS]

If I select DVD instead of DUAL-LAYER DVD, Toast 17 produces a disc image that's not 4GB but one that is 7+GB.  It will fit the DUAL-LAYER disc and solve my problem, but they need to fix this and number of other glitches (compress to fit option, misaligned 16:9 menu highlights, audio handling for video with mono tracks, etc).

 

[bimicher]

Toast is not off the mark. Source file sizes do not mean very much as the time length of the video is more important. A standard DVd can only hold just hold about 60 minutes of best quality DVD video while DL DVD can cold under 120 minutes. You can of course squeeze more video pn the DVDs but only at a lower bitrate which means lower quality. The program works correctly in this regard and there is nothing to fix. The compress to fit option is basically meaningless since automatically reduces the bitrate to fit the DVD

[JJDVS]

I disagree. 

If you select 4GB DVD, it should correctly produce a 4GB size image.  It gives you a very off the mark estimate as you add content to the disc, and you can't rely on it.  Using iDVD as an example, it doesn't create a file that's too big.  It will warn you if you are over, not say this is ok, you are within the limit, then give you something you can't use.  iDVD has other issues, but at least it accurately says what will fit and what won't.

Compress-to-Fit should do just that, compress as needed to fit the desired disc.  But it doesn't.  Again, it often creates something that is too bit to fit.  If I use compress-to-fit and it asks for single or dual-layer, then I expect the end result to fit whichever I chose. 

[Kal-El]

I’m having the same problem but with Blu-ray. It’s maddening, and very confusing, because I have no way of accurately estimating how much content needs to be removed in order to produce a disc image that will fit on a BD DL. I saw elsewhere that going into the settings and changing ‘re-encode’ to ‘never’ can solve the misleading size estimate issue, but not re-encoding also means fitting a LOT less content onto the disc.

 

Anyone with constructive input / solutions would be most appreciated.

[cdanteek]

A disc with a 25GB capacity is the equivalent of 23.28 gibibytes, depending on whether you’re using a base-2 system (binary) or a base-10 system (decimal). Also, some of that space is reserved as overhead for the file system, as well as error-correction information. So really, you’re getting a true recordable capacity of 23.28 gibibytes instead of the 25GB stated on the package for a single layer disc.

It is the same for dual layer discs. Normally rated at 50GB, in practice they can record about 46.57GB of data. Again, this is due to the differences in the way capacity is measured and the small percentage of space reserved for file system and error correction information.

[Kal-El]

Which makes sense to me, but I don’t get why Toast says the space used is one size but then the disc image it creates turns out to be another (larger) size.

 I had a project that was set to take around 45 GB according to Toast, but when I actually made the disc image it ended up being 52 GB (too large to burn to a BD DL disc).