Well… “Epicyon is for people who are tired of big anything”. I wouldn’t say 654Mb not to be “big”!

You will want to copy the video stream without re-encoding to save a lot of time but re-encoding the audio might help to prevent incompatibilities:

ffmpeg -i v.mp4 -i a.wav -c:v copy -map 0:v:0 -map 1:a:0 new.mp4

-map 0:v:0 maps the first (index 0) video stream from the input to the first (index 0) video stream in the output.

-map 1:a:0 maps the second (index 1) audio stream from the input to the first (index 0) audio stream in the output.

If the audio is longer than the video, you will want to add -shortest (or possibly -fflags shortest) before the output file name.

Not specifying an audio codec, will automatically select a working one. You can specify one by for example adding -c:a libvorbis after -c:v copy. You can also use -c copy to avoid re-encoding the audio, but this has lead to compatibility and synchronization problems in my past.

https://highdiceroller.github.io/icepool/apps/icecup.html?p=eq&c=GYJw9gtgBAlgxgUwA5jAG1hFIAuUAmAUIWAK45LkAUAzFAAIFUBsAlADRQDkN+zXrEuUo4q+KgCYADKwB0EGPnxoEVAJwduCpSqhhgUNfmkChFauOlzty1QEY7mrjd36oD41NNA

This is Daniel from Amiga-News.de. I happened to see your Mastodon post about Serena OS: https://mastodon.uno/@paoloredaelli/113001607364175122

I would just like to point out that it was us who originally reported about it (also about an earlier version): https://www.amiga-news.de/en/news/AN-2024-08-00046-EN.html

Including a detailed explanation from the developer himself. From what I’ve seen, many websites, blogs and news sites have read our articles and reported on this project, but very few have actually referenced us.
This is very frustrating as we are all pure hobbyist editors who research and write articles for our non-commercial site in our spare time.

In this respect, I would be very grateful if you could perhaps add this to your post or write a new one.
Thank you very much!
Daniel