Avidemux joins MP4s but doubles combined file size of the parts

[gumbygum]

When I join a few MP4 files using the Append function of Avidemux, why is the resulting file twice the size of the combined sizes of the joined files? Andy’s FLV Joiner never does this, the joined file size is always the sum of the combined parts. Unfortunately Andy’s won’t join MP4s, even if they have a FLV extension.

I wish I could find an equivalent to Andy’s for MP4s. I just downloaded MP4Tools but it failed to join my MP4 parts. Could it be because I installed it as a portable app when there’s no indication that it is portable? Or could it be because the MP4s have FLV extensions?

I also tried changing the FLV extensions to MP4 and ran it through Avidemux again, but the result was the same puffed up filesize, even a tiny bit larger.

I’m using Avidemux Portable version 2.6.10. Settings are Copy video and audio, output MP4.

Thanks for any help.

[Baldrick]

Copy mode should just copy the video and audio. But maybe avidemux might have added the video tracks twice or something. Open the joined mp4 with mediainfo or mkvtoolnix or mymp4boxgui and see if it contains dual video/audio tracks.


And try join your mp4s with mymp4boxgui or use mkvtoolnix to join and output a mkv.