All single & dual layer DVD blanks have the same amount of space regardless the brand. When you author a DVD you have that amount of space, minus what's taken up by any menus and scripts for the title video file(s). Many people find a bit rate calculator helpful to determine the bit rate to use encoding that video, up to a max around 8 -- the lower the bit rate the smaller the files. Ideally DVD video should be encoded using VBR, Variable Bit Rate, and don't forget the space taken up by the audio -- the audio bit rate and number of channels determine how much space the audio takes up. Generally you want to output your DVDs to a folder, rather than ISO, and many recommend [myself included] ImgBurn to burn the disc, especially with dual layer. If your new DVD is *slightly* too big, the free DVD Shrink [or older versions of Nero Recode] can help -- it'll quickly copy your DVD to a new folder, reducing the size to pretty much the exact max allowed.

Can't say why Leawo DVD Creator gives you that warning. Don't know if the warning's false, if you're using the app to encode your video, if when you say the same movie you mean the same, already encoded file etc. I do know that some authoring apps include boilerplate scripts for menus etc., whether they're used or not, and that can add to the size.

videohelp[.]com/software/sections/bitrate-calculators

videohelp[.]com/software/DVD-Shrink

Antonio Alvarez, that oone is easy to explain ;-) Freemake is not restricted to standard DVD-Video profiles and so can downsize the video resolution dynamically to make space and tune dynamically tune the sound track encoding to make the desired videos to fit on the required size DVD-ROM. It kinda feels like magic but the more you squeeze in the the lower the quality in terms of resolution of both audio and video. That is its unique selling point even though its Freemium. This and every other DVD-Video authoring software is locked into the original DVD-Video profiles and many won't even let you choose the profile or even 1.4G mini DVD-ROM sizes. let alone choose video resolutions and audio bit rates not normally associated with DVD-Video discs. Of course there is a risk that some of the dynamicaly generated profiles generated by freemake may not play on all stand alone DVD-Video players...
It does not take too many attempts to learn what you can get away with on your target DVD-Video players.

mike, with freemake it can record 18 to 20 hours of video on a single DVD by dynamically modifying the encoding profile to make the videos fit. It is its USP these GUI's on top of GPLv2 DVDAuthor invariably do NOT know anything about DVD-Video capabilities and are locked to a couple of DVD-Video profiles and generally fill up the DVD in 2 hours or less of video.
TK

Alafosra, Is it blu-ray century? I have not been using CD, DVD or blue-ray for many years now. I don't even know where to buy old media like this anymore.

Gunnar, you can find media for dvd and blue ray on Amazon, Ebay, Micro Center, etc...

Gunnar, Even though we are in a streaming atmosphere now, there are probably a majority of people still using Blu-Ray and DVD"s. Just go to Walmart, Target, Best Buy, online. Just because it doesn't fit your situation, doesn't mean that others are in your same "boat". I have used this company's products for several years and they are very good. If you want to make a DVD to send for Grandma for Christmas, this is a great way to do it. She probably still has a DVD player.

"Give us some BLU-RAY copier, ripper etc..."

They're somewhat rare because the company behind one of the DRM methods used took Fengtao [DVDFab] to court in the US & won a default judgement -- they can't use a com web site, and US companies cannot deal with them. That said, there have been a few on GOTD, and the MakeMKV beta is always free.

"I have not been using CD, DVD or blue-ray for many years now."

Blu-ray, FWIW, is likely the highest quality video you can get your hands on, even better than 4k streamed, and of course 4k Blu-ray is even better. But it's also a hassle, so more people use streaming, which is Much easier.

Gunnar, it is DIGITAL century actually but at optic media it is BLURAY. I am a collector, so there is no better media then BLURAY... 10 years ago, it was DVD but now it is BLURAY...

Gunnar, I prefer physical stuff I own them its mine.

Streaming and cloud services you don't own what you get, you pay for nothing really and they can take away any movie or tv show edit them to remove what they think is offensive because you know your not important.

No physical you own, it can't be removed it can't be edited and its way better.