Avidemux Forum

I have a 854x426 H264 .mp4 video that plays onscreen in all of the Windows 11 players I've tried (Pot, VLC, WMP, MPC, etc.) as if it was 16:9, when the video was intended to be 4:3, since everything in the video is stretched horizontally (everything looks wider/fatter than expected). If I open POT Player and tell it to manually force the aspect ratio to 4:3 it displays fine.

Is there a way to use AviDemux to fix this? I don't need to change anything else about the video (audio, resolution, etc.), except to make it show onscreen correctly. I'm happy to change the container file format. I've tried using MKV Muxer output with Force Aspect Ratio (DAR) of 4:3, re-encoding to HEVC, and a few other things, but nothing fixed the issue yet. This is with the latest Windows development release 2.8.2, but I have the same issue with 2.8.1.

I'm new to video encoding and AviDemux. I have only used it to crop videos before this.

I tried a few times to paste in the file details from AviDemux and MediaInfo, but I was getting this AntiSpam error: "CleanTalk: *** Forbidden. Message seems to be spam. Anti-Spam by CleanTalk. ***"

If you re-encode, use Filters/Transform/swsResize. Untick "Lock Aspect Ratio".
Set either width to 568  OR  height to 640. The former will reduce the size, the later will enlarge it.

Rana,
Yes re-encoding is the cleanest solution that works for every playback.

There is a way to adjust the Aspect Ratio for 3rd party players like VLC, but it does not work for Browser or TV app playback.  The math is a little crazy to figure out, because the settings can only be whole numbers.  So for any aspect ratio change you have to go high enough with numbers to no longer need decimal values.

Online Calculator is here: https://www.producerelease.com/blu-ray/parcalc.htm#wrapprcalc

This adjustment works only for VLC or similar 3rd party app players.

Video -> Copy
Audio -> Copy
Output -> MP4 Muxer --> Configure -> Force aspect ratio --> DAR: 4:3

Otherwise, you can do similar with ffmpeg.

That is lossless (so no need to re-encode).

How a player interprets that may vary, but try it & see if it works for you.

(And any decent player should have rather simple method of interactively changing aspect ratio for any "out of wack" video.)