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MPEG2 Aspect Ratio

Posted: Tue Jun 18, 2024 9:23 am
by Garmon
Has anyone else noticed that MPEG2 files extract from Blu Ray at a display resolution of 1080x1080? I can use MKVToolNix to change the display width to 1920 but I was wondering if there was a fix for this. The problem seems specific to MPEG2 files.

Re: MPEG2 Aspect Ratio

Posted: Wed Jun 19, 2024 2:09 pm
by dcoke22
I don't think I've ever encountered a blu-ray with MPEG2 files. Usually AVC or VC-1.

Are you reading files from a blu-ray recorder perhaps?

Re: MPEG2 Aspect Ratio

Posted: Wed Jun 19, 2024 10:52 pm
by Radiocomms237
I note down the MediaInfo of every file I rip and there are absolutely tons of Mpeg2 files on Blu-ray, mostly for Special Features, but occasionally for Main Titles.

As an example, the first set of notes I happened to lay my hands on were for the UK Blu-ray version of Spider-Man 1 (UK-32161-BD-DLX) and the very first SF that I have listed is:

Code: Select all

The Mythology Of The 21st Century: 
Mpeg2 720x480i (display size 640x480i) NTSC (45840 frames @ 29.970 fps (Constant) = 00:25:29.528000000)
I have mentioned this elsewhere but, the aspect ratio for just about anything listed as 720px in width is almost always different to the actual display size. Although I believe there is some old DVD "standard" somewhere that dictates that?

Having said that, I don't recall ever having seen a display height on a DVD or Blu-ray that's been incorrect, but I supposed it would be possible to enter it incorrectly when authoring the disc.

If we're only talking about a single disc, or perhaps all the discs from a single box set, then I'd guess it's simply a mistake made when the disc was compiled.

If you're seeing this on multiple (or all) titles then I'd have to say that there's something hinky with your specific setup as I've ripped close to ten thousand discs and never once seen "1080x1080" listed (and I do take note).

Could you tell us what title (or titles) that you've seen this with?

Re: MPEG2 Aspect Ratio

Posted: Sun Jun 23, 2024 9:31 am
by Garmon
It's happened with several discs but I haven't noted which. However I JUST ripped the Shout Factory 2019 Blu-ray of Galaxy of Terror. The extras that were encoded in MPEG2 came out at 1080x1080. Changing the display width tag to 1920 with mkvtoolnix fixes the problem. But I'm wondering if there is a workaround.

I was speculating that MPEG2 files on Blu-ray are anamorphic. Stored at 1080x1080 and stretched by the player. The AI's I asked all said no, they're stored at display resolution.

Image

Re: MPEG2 Aspect Ratio

Posted: Mon Jun 24, 2024 5:54 am
by Radiocomms237
Garmon wrote:
Sun Jun 23, 2024 9:31 am
~ I JUST ripped the Shout Factory 2019 Blu-ray of Galaxy of Terror. The extras that were encoded in MPEG2 came out at 1080x1080. ~
I have that exact same release, but I can't look up my notes on it as I've been playing musical hard drives in my NAS and the drive it's on isn't mounted at the moment.

But I don't remember anything like you describe.