Seems basic.. surprised we are still waiting for this after four years

In Quicktime Player Version 10.5 (1086.4.2) there is a "Remove Audio" feature in the Edit menu. Then you can just drag the new audio file to the QT player window and save. SUPER Helpful!!! Unfortunately it is just a few versions of QT or maybe it is OS dependent but this does exactly what you are looking for. I use it all the time for making mix samples for clients when ProTools doesn't feel like bouncing a QT file.

Please add this feature!

this is a must-have feature ..

This isn't a feature yet and the request has been around for over 2 years? Wow... I thought I was finding a tutorial, not a feature request. Yes, this would greatly improve Media Encoder.

Dang, I thought this feature was a part of Media Encoder and tried to figure out how to do it just now. I must've been thinking of Quicktime Pro. Please make this a thing!

Just chiming in with support for this idea. Swapping audio to locked picture is common in my workflow and this would save time in a pinch.

This would be really useful.

Is this a feature yet? I need to merge audio and video QT refs in media encoder because I also need Encoder to turn it into an h264 with burn in timecode.

I was looking for that feature in Media Encoder and Google lead me right to your suggestion Marc Zwaneveld. So, of course you've got my vote for this feature.

I want this! When working with images sequences, adding sound back is such an unnecessary hassle.

This feature request has me really missing the "Append" feature of QuickTime Player 7 Pro.

I'd love this feature too, although the audio and vision duration would need to make, or the audio would need to be shorter.

Working in a broadcaster the mix for a cut can change a lot, being able to replace the audio mix of a cut without doing the above would be helpful.