user5416: I have problems with my Premiere Pro. It is first time this has happened, and I cannot understand why. 
I am creating a timelapse from my images. When I want to export media, I choose format H.264 (not H.264 Blu-ray), dimensions 1920x1080. Output name is visible as "Sequence02.mp4". 
After export is finished, there is a file "Sequence02.m4v" on disk. Why? What causes Premiere to change file format by itself? I used Premiere before and this never happened. Maybe I'm using some different setting, but what could cause this change?

user6273: The most likely cause for this are faulty multiplexer settings. In the export window, make sure both "export video" and "export audio" are checked (see screenshot). Then go to the multiplexer tab. The multiplexer gives you control about how your video and audio stream will be muxed (bundled) in one file. Make sure "mp4" ist selected, and the stream-compatibility (the second option) is set to "standard".



user11764: I encountered the same issue when I turned the sound off in the sequence.  When I re-enabled audio export, even though I didn't want to or need to, it saved as an mp4 again.

5416: <p>I have problems with my Premiere Pro. It is first time this has happened, and I cannot understand why. </p>

<p>I am creating a timelapse from my images. When I want to export media, I choose format H.264 (not H.264 Blu-ray), dimensions 1920x1080. Output name is visible as "Sequence02.mp4". </p>

<p>After export is finished, there is a file "Sequence02.m4v" on disk. <strong>Why?</strong> What causes Premiere to change file format by itself? I used Premiere before and this never happened. Maybe I'm using some different setting, but what could cause this change?</p>
 6273: <p>The most likely cause for this are faulty multiplexer settings. In the export window, make sure both "export video" and "export audio" are checked (see screenshot). Then go to the multiplexer tab. The multiplexer gives you control about how your video and audio stream will be muxed (bundled) in one file. Make sure "mp4" ist selected, and the stream-compatibility (the second option) is set to "standard".</p>

<p><br>
<img src="https://i.stack.imgur.com/SlDim.jpg" alt="enter image description here"></p>
 11764: <p>I encountered the same issue when I turned the sound off in the sequence.  When I re-enabled audio export, even though I didn't want to or need to, it saved as an mp4 again.</p>
