MP4 encoded with Handbrake (H.265 Apple VideoToolbox): muxer can't open

[riji]

MP4 video encoded with Handbrake hardware setting:
hardware: H.265 Apple VideoToolbox Avidemux muxer can't open

I recently got a Mac Mini M4 Pro. So for encoding (MP4 video file with burned in subtitles) I started using Handbrake again. This is because this app in the Preset setting (Fast1080p30) has an option: Hardware and with it the choice: H.265 Apple VideoToolbox (2160p/1080p).
This provides ample speed gain with decent quality.
My problem is that when I want to open such a file in Avidemux, the muxer cannot open the file.
Is there a solution for that?
------ Translated with DeepL.com (free version)

[eumagga0x2a]

Does the issue persist with the latest available 2.8.2 nightly build? And with a self-compiled binary off the latest git master?

Not sure about official nightlies which are x86_64, locally compiled arm64 builds support VideoToolbox encoders for H.264 and HEVC.

[riji]

Avidemux 2.8.2 Qt6 241110-02h54m
I downloaded this version, but again it does not work.

[eumagga0x2a]

Please provide a sample video (shorter and smaller is better) via WeTransfer (no account and no email address required, despite the website trying to suggest the opposite), Mega, Dropbox or Google Drive then. Thank you.

[eumagga0x2a]

By the way, you meant for sure "demuxer", not "muxer", didn't you?

Muxer is for combining (multiplexing) video and audio streams into a container file when saving a video.

A demuxer reads a container file to obtain video and audio (and, in principle other types of data) from it to load them in an application like Avidemux.

[riji]

I open in Avidemux my mp4 file obtained from Handbrake with setting: hardware H.265 Apple VideoToolbox 1080p.
When I cut a part of it on a keyframe and want to save, I got the message: "MUXER Cannot open".
I have done this with the MP4 file from internet:Cosmic Eye (Original HD Version); so it's easy to try out.

[eumagga0x2a]

Please specify the muxer you try to use. Not all muxers are compatible with HEVC, but MP4 (NOT "MP4v2"!) and MKV really should.

[riji]

Before I used MP4v2 (since years).
Now I have switched to MP4 and this do the job; so I'm saved.
Thank you very much.