Avidemux Forum

Try using a more recent version of Avidemux

https://www.avidemux.org/nightly/vsWin64/

Hello,

The same file opens properly in other tools.

Error output is:
Assert failed :0 at line 116, file F:
\jenkins\workspace\VS2019_no_import\avidemux_plugins\ADM_demuxers\Mp4\ADM_atom.cpp

Please let me know how I can share the problematic MP4 file.
This post has restrictions in format and size for attachments.

Thanks in advance

Quote from: MacKenrick on July 15, 2026, 11:14:25 PMOn my Windows 11 computer running Avidemux 2.9.0,

Please clarify what "Avidemux 2.9.0" is and where you have got that from. The hint: there is no such (official) version. The last release was 2.8.1, meanwhile ancient, the development has slowed down on the way to 2.8.2 with relatively recent nightly builds being the best option for the purpose.

To trim the end portion of a video in copy mode in pre-2.8.2 nightly builds as well as in 2.8.1 release (cropping is something completely different: removing outer portions of the picture), set the A marker where the deletion should start, reset the B marker (if not already at the default position past the last frame), then press DEL (or "Edit" --> "Delete", or just click on the big red button in the center of the navigation bar).

I am unable to crop to the end of a video.

On my Windows 11 computer running Avidemux 2.9.0, I cannot crop to the end of a video like I can with the older Avidemux 2.8.0 on my old Windows 10 computer.  On the old 2.8.0, I move the slider to where I want to start the crop, select the Go To Next Keyframe, then select Set Start Marker.   I then select Go To Last Frame and select Set End Marker.  I then select Edit and Cut.  The entire last part of the video is cut out.  If I try that on the new 2.9.0 and try to save the video, I get an error message. This happens with every video I try to trim the end on.  The only way I can crop to near the end of the video, is to get to the point where I select Go To Last Frame, then select Go To Previous Keyframe, then select Edit and Cut.  This method leaves the very last few seconds of the video, that I do not want, still on the saved video.

Why doesn't the newer 2.9 version of Avidemux allow me to cut to the end of the video?  How do I fix this problem?  Thank you for your help.

Fosshub Avidemux download page works as before, maybe the way the link is set on Mean's Avidemux homepage is a problem (http instead of https).

You should be better off using a relatively recent nightly (developer) build because the last official release has grown long in the tooth.

nevermind, removing / just sends to some other page that redirects me  back, making it a loop!!!!
i can't offiicially download avidemux for windows now

the slash at the ending of link makes it "This ___ page can't be found"
Just removing it (on brave browser at least) fixes it. The slash at the ending of the link. I dont think i can send the link without being flagged as spam

When saving anamorphic video to a MP4 container with Avidemux, you need to specify desired display aspect ratio in the configuation of the MP4 muxer.

Quote from: DapOrp on July 03, 2026, 09:26:33 PMwill this appear in a nightly build?

Yes, in any future nightly build.

I would also usually recommend to prefer self-reliance over any dependency on official supply (independence requires just a Linux installation with quite a bit of memory and disk space), albeit I would need to verify that the old way to cross-compile Avidemux on Linux for Windows still works, or that the new one (requires DevPod, e.g. as AppImage, uses Docker) works sufficiently well.

I have converted a VOB file to MP4 using handbrake converter . This tool was the only video converter that was able to do the conversion Perfect without Narrowing the video to squashed !! I tried just about all other video editor/ convertors - Handbrake is the Only one that does it.
But Now when I use Avidemux to trim this video using "copy" vide Only mode , the same thing happens again & the video is squashed. What other Free Alternatives can I use to trim the mp4 video without Loosing the Header information that Handbrake had put in