Changing aspect ratio of a MPEG file

[oodini]

Hello,

I've got a MPEG movie, but when I read it (with WMP, BSPlayer, or other), the video is sqashed, and there are black bars above and beneath the video. But when I open it in Premiere, the video is fine.

I guess there are somewhere in the file data about the video size, and that this info is wrong. Is it possible to modify it, without compressing again the video (I tried, but the video is then very bad) ?

Note: the settings in DVDPatcher seem OK. But I read the file in a player, troubles...

Thanks.

[oodini]

Up

[guns1inger]

What is the resolution of the file ?

[FulciLives]

It could be that the MPEG file is flagged as 4:3 when it should be flagged as 16:9 ... or vice versa.

If you demultiplex (demux) the MPEG file so you get a MPA/M2V video only file and an AUDIO only file (will be MPA/MP2 or AC-3) you can then run PULLDOWN.EXE on the MPA/M2V file to change the asepct ratio from 4:3 to 16:9 or from 16:9 to 4:3

You can then multiplex (mux) the VIDEO and AUDIO file back into a single MPEG file.

It might be possible to do this without demultiplexing but I don't think PULLDOWN.EXE will work that way (maybe someone else can confirm or deny that).

Of course this is assuming the aspect ratio flag on the MPEG file is incorrect. The problem could be something entirely different.

I would try playing the MPEG file with a "standard" DVD software player such as PowerDVD or WinDVD instead of BSPlayer or Windows Media Player etc. since those 2 DVD players will properly resize the video as per the flags on the MPEG file. If they resize incorrectly then chances are the flags are wrong (4:3 when should be 16:9 or vice versa). If the resize is done correctly then the problem is NOT with the MPEG file but the way BSplayer etc. is handling the file during playback.

- John "FulciLives" Coleman

[FulciLives]

What is the resolution of the file ?

When it comes to MPEG-2 DVD spec I would like to point out that only the 720 width resolution or 704 width resolution can be 16x9 whereas the 352 width resolution should only be 4:3 but I have known people to make 16:9 video with a width of 352 but this is out of spec and will not work on all stand alone DVD players although some (few I asm assuming) can handle the out-of-spec 352 width 16x9 videos.

- John "FulciLives" Coleman

P.S.
Everything I said in my first post above assums that the video is standard 720 width or 704 width and is a MPEG-2 DVD compliant video file.

I just realized we could be dealing with soemthing else such as a SVCD video file. So please tell us the resolution. If you don't know try loading the MPEG into VirtualDubMod (not the regular VirtualDub but VirtualDubMod).

[oodini]

The size is 352x240.

[FulciLives]

The size is 352x240.

That is the resolution usually used for the VCD format which is MPEG-1 video. You can use MPEG-1 video on a DVD with that resolution and you can also use that resolution for MPEG-2 and again that would be proper to use on a DVD (although please note that the VCD spec uses an audio sampling rate of 44.1k whereas DVD audio must have a sampling rate of 48k instead of 44.1k).

Most of what I said before (in my other previous posts) does not apply to the file you are talking about now LOL ... but ... I still think that if you play this MPEG video (be it MPEG-1 or MPEG-2) with a "standard" DVD software program (like PowerDVD or WinDVD) then it should look A-OK aspect ratio wise even though it looks odd with other media playing software such as BSPlayer.

- John "FulciLives" Coleman