Aspect Ratio help

[fru$trated]

Hi All

I am converting my old home dvds to mp4 to play from a hard drive and the aspect ratio of the converted files is 720 x 576.

My question is this, when I play these on the TV, some of the converted files fill the whole screen whilst others do not. Why id this the case?

When I play the original discs on a dvd player, they also fill the whole screen so am confused why this does not apply to the converted file.

If you need more detail on anything please let me know.

Thanks for your help.

[JVRaines]

What software and settings did you use to create the MP4 files? How are you playing the MP4 files on your TV?

720×576 is a storage aspect ratio (SAR). It's not the display aspect ratio (DAR), which is 4:3 for legacy video or 16:9 for widescreen. The decoder has to stretch the center 704 pixels to make the DAR come out right.

[Cornucopia]

The formula: Hrez/Vrez * PAR = DAR is universal for video calculations.

Dvds all use non-square PARs, whether NTSC or PAL, whether Fullscreen or Widescreen, whether full rez or 1/2 or 1/4 rez.
When you reencode to Mp4s, you may have the option of retaining those non-square PARs or of losing them and using square (1:1) PARs, or even of correcting/subverting them and using different non-square PARs. Depends on the app & settings though.

Scott

[fru$trated]

Hi Cornucopia and JVRaines

Thank you both for the help.

The software I am using is Wondershare video converter ultimate.

Since your posts I have looked into the settings I have been using and found that it is the resolution setting that is 720 x 576. I have also since found an aspect ratio setting under the edit>adjust options.

Is there something I need to be doing on this option also?

I will post some screenshots later on if this helps.

Thanks for your input so far.

[Downgraded286]

You mention home DVDs. Were they all shot with the same camera? My suspicion is, assuming they're all 720x576, some were shot in 4:3 (resulting in actually displaying 720x576) and some shot in 16:9 (resulting in actual display resolution of 1024x576). Probably your TV upscales the video to fill the whole screen, but at 4:3 there will be black bars on the side, but at 16:9 it can fill the whole screen.

You can probably manually adjust the videos in your video converter to come out as 16:9 if you wish, but they will be stretched out.

[fru$trated]

Hi Downgraded286

Thanks for your reply. Is there any software available to analyse my dvds and video files so I can see their properties to identify if they were shot in 4:3 or 16:9?

When my dvd player plays the disc in full screen, the video looks fine ie not stretched etc so I am ok to manually adjust these however am struggling to figure out the best bay.

[manono]

My suspicion is, assuming they're all 720x576, some were shot in 4:3 (resulting in actually displaying 720x576) and some shot in 16:9 (resulting in actual display resolution of 1024x576).

I think you mean to say 768x576, or some other 1.33:1 ratio. 720x576=1.25.

Is there any software available to analyse my dvds and video files so I can see their properties to identify if they were shot in 4:3 or 16:9?

Yes, about every video file information tool will tell you if the DVD is 4:3 or 16:9. You could even use your eyes as it's quite easy. Anyway, MediaInfo, GSpot, or open a VOB in DGIndex and run the Preview (File->Preview). It'll give the Aspect Ratio as either 4:3 or 16:9.