Dummy Proof Help for Aspect Ratio

[hgurol]

Hi,

As I understand it, to change the aspect ratio of a video without having any distortion on the picture like no stretching and no shrinking, the only way is either using black borders, or I have to crop, zoom, pan the picture. The latter is not an option for me.

My source files are already encoded for PC and Im gonna use them on PC after I do my own encoding. Both my source and destination PAR is 1:1 so I thought I can change the aspect ratio without using the black borders but in all my tests either the picture stretches or it shrinks.

So, I guess using the black borders are my only option. Right?

Thanks...

[manono]

So, I guess using the black borders are my only option. Right?

Maybe not. What's the source format and resolution? What's the destination or final format and resolution? What encoder and/or other programs are you using?

Why are you changing the aspect ratio? Is something wrong with the source videos? Ordinarily, if the aspect ratio of the video doesn't match that of the display (your computer monitor in this case), the player adds the black bars, not you. For example, a 1.33:1 video (640x480, maybe) played on a widescreen or 1.78:1 monitor or TV set has black bars (pillarbars) added to the sides by the player.

[hgurol]

These are a bunch of video files download from internet and they are all encoded before with 100s of different settings. My job is to re-encode them and then they will be used for streaming through a website. While Im doing this I want to bring them to a standard. Like I want all of different variations of wide screen sources to have an aspect ratio of 16:9 with a 480*270 resolution. I will always encode with h.264&aac as part of my own standard. Not all players add that black borders themselves. Especially not the flash player, nor the browser build-in HTML5 player.

Im on Linux and using Avidemux for my encoding stuff. Tried a couple different GUIs and found this one less lacking on features than the others. Im open for suggestions . I guess the best is learning the use the ffmpeg on the command line but right now that's a little scary for me.

The file Im doing my practices and learn my stuff has a resolution of 624*256. Its DAR is 2:40 says the media info tool. Its an Xvid & mp3 format file. I dont know how to look at the PAR but somewhere I read the PAR would be always 1:1 when the video is encoded for PC. So I believe both the original PAR and the destination PAR is 1:1.

[manono]

Not all players add that black borders themselves. Especially not the flash player, nor the browser build-in HTML5 player.

I don't know much about that particular subject but you said this was all for the PC initially, and not for internet streaming. But isn't the YouTube player based on Flash? It adds black bars where needed to fill out their screen. I upload a 640x480 video and get it available at 480p and when played they add black bars to both sides of the video for their widescreen player. I redownload it and it's still 640x480. No black was added during their reencoding of it.

[hgurol]

I dont know the details about youtube. I have always thought they were adding the black borders during their encoding process.

In my case, not all of the web players Im using, even the gnome player of my linux doesnt add the black borders.

Anyway, what I have figured is; I need to add the black borders myself if I dont want any shrinks and stretches on the picture. As goes with my sample the 624x256 original would be 480x196 in the same aspect ratio. And to make it 16:9 which also brings it to my resolution standard 480x270, I should add 37px black borders both on the top and bottom of the picture.

This is the way do it, right?

[manono]

This is the way do it, right?

Yes, if all your source videos are 1:1. However, it's probably not such a good idea to add an odd number of pixels above or below. Rather than 37/37, I think 36/38 would be better.

[jagabo]

DAR = PAR * SAR

https://forum.videohelp.com/threads/322346-same-resolution-but-difference-in-display-w-...=1#post1995959