Hi Borate
Regarding Prism, it doesn't rip protected DVDs, which is perfectly legal if it's for personal use and/or if one has the publisher's permission (which I do have). And as far as I can tell, Handbrake is only available for 64-bit versions of Windows, whereas I have Windows 7, which is 32-bit.
In the end I got the original MP4 files from the publisher, from which they had created the DVDs, and I edited those in Videopad - and I can confirm that I was able then to edit them (removing the unwanted sections) without any synching problems resulting. Many thanks for your help with troubleshooting that problem.
However I have now another problem. The original DVDs - and also my edited MP4 files after being burnt to a DVD - play in widescreen format when I play them on my DVD player through my widescreen television; but two out of three of them (it's a three part series) play on my PC with a 4:3 aspect ratio by default, and they then look severely distorted, as the picture is actually meant to be displayed with a 16:9 aspect ratio.
I can get round this in VLC media player by changing the aspect ratio when playing the video to 16:9 ; and as I say my DVD player automatically plays it with a 16:9 aspect ratio. However, if I try to add a menu to it using Nero Video, even though I use a 16:9 image as the background image, Nero Video sees that the video has a 4:3 ratio, so it crops my background image to have a 4:3 ratio, and when this then plays in widescreen it looks distorted.
So I want to convert the MP4 to have a 16:9 ratio, which is the ratio it should have. I don't know why the publisher's MP4 files have one episode with the correct aspect ratio and two with the wrong ratio, but that's all they have - and they do all play with a 16:9 ratio when played on a DVD player rather than on a DVD ROM drive on a PC.
The one MP4 they gave me (episode 3 of the series) that plays at the correct aspect ratio by default on a PC has a frame width & height of 720 x 574. The other two episodes both have aspect ratios of 704 x 576.
Is there any way I can convert the MP4 in Videopad to have the correct aspect ratio? I tried exporting my edited video and using the setting "Auto match content but force 16:9" but that makes things much worse - it still displays a square image rather than a widescreen one, but it now can't be changed to a widescreen image when playing it in VLC and it no longer plays with the correct aspect ratio on my DVD player - in other words, it hasn't actually resized the image to the required aspect ratio - instead it's just put the square image onto a black widescreen background!
So is there any way I can convert the aspect ratio of the videos' images of the two episodes which have the wrong default aspect ratios on a PC, to what they should actually be (which is 16:9)?
Dave