I have lots of VCDs which I want to convert to DVDs. Can you suggest me a software with GUI which would do it for me?
I suggest qdvdauthor or dvdrip as gui based. But i HIGHLY suggest using console tools like ffmpeg, mencoder and similars. They do a fast, excellent job.
You can also MAKE an iso of a vcd with acetoneiso, brasero (Which comes by default in Ubuntu) or k3b (Which comes by default in Kubuntu) and then burn it like dvd with something like devede.
Remember that you can not make a video with higher quality than what it has in the beginning. In your case you cant make a vcd quality movie have a dvd quality. It is like a dvd quaility trying to have a blue-ray quality.
All the tools i suggested can be found in the ubuntu software center or synaptic.
If you are going to use all the tools for that then you should first make the vcd to iso and then test it by viewing it with vlc. If all is good then burn it with devede which will make it into dvd format (With an optional menu) and you can just burn it and watch it in your media player.
Us the following in console to have them all installed:
This should have you ready to transform anything to dvd.