Nero 2017 - Losing Widescreen Format

[KK1977]

I am converting imported .VOB files into MP4 files using Nero 2017.

Settings that I use are

Format: MPEG-4 (WMV, Flash Video, MPEG-1, MPEG-2, AVC, AVC-HD (Blu-Ray), AVC Ultra HD (4K) are the other options)
Aspect Ratio: 16:9 (4:3 is the only other option)

I have always used these settings over the years with exported videos retaining their widescreen settings but recently I've noticed that widescreen is getting lost (smaller picture appears when watching on TV). I have changed my television during that time but I didn't think that would make any difference.

Does anyone have any recommendations on how I can overcome this please?

Thanks!

[davexnet]

Play your converted file in mpc-hc or VLC media players on the
computer and confirm it is as expected

[jagabo]

PAL DVDs use a 720x576 frame size (5:4) and a flag that tells the player to display the video at 16:9 (or 4:3). Programs that convert to MP4 can encode the video with the same 720x576 frame size and flag it for 16:9 display, they can encode the video with a 720x576 frame size without specifying the display aspect ratio, or they can resize the frame to a 16:9 size (1024x576, for example) and let the player use the frame AR as the display AR. The first method doesn't work for all players -- they will ignore the flag and play the video at its frame aspect ratio, 5:4. The second method is guaranteed to display with the wrong AR, And the third method ~always plays properly.

Use MediaInfo to determine which method was used and force the conversion program to use another.