The MPEG-4 format is not a supported video format in Vegas Pro

@Dexcon Are you sure as my experience is different. My mp4 1080 50p files rendered from VP21 Build 315 with either Magix AVC or Sony AVC are like Bob's "Format MPEG-4" and they import perfectly back into VP21. See info below:

MP4 is part of the MPEG-4 standard and is compatible with VEGAS.

For example, AVC rendered to MP4 through VEGAS has metadata as

Format                         : MPEG-4

as is all of the Canon MOV AVC I shot with Rebels over the years. It all works fine in VEGAS.

@Bob_H Is it possible to get a brief sample of footage for testing? The only slightly unusual thing here I see is the resolution 960x720.

@Dexcon @Bob_H  All my MPEG-4 containers with AVC codecs load just fine. Those were created in Vegas 17 with Magix AVC profiles -- Mainconcept and NV, with and without audio. Did not need Quicktime deprecated feature or legacy AVC to load them into Vegas 22 build 122. Something else must be wrong.

@Bob_H It's a mystery as to why your files don't open in VP21. Could you please upload a short one to somewhere like Google Drive and give us the link so we can download and try.

Your Variable Frame Rate is problematic

What VFR? I read it in the Media Info as constant. Have I missed something?

@EricLNZ

Oops! I must have had two posts open at once. Retracted.

@Bob_H Please upload a short sample of your source video to Drive or Dropbox, not Youtube or this forum, so that others may check it on their own systems.

I see no obvious reason that it would not open in Vegas.

I just now tried and failed to import the MP4 file that is linked to below on Google Drive. Filename is, "1982 02 15 On a sled (from Reel 06).mp4". Before converting the MPG files to MP4 using Vegas 19, I know that I tested and was able to import the "converted" MP4 files into Vegas 19 for possible future editing. Therefore, I do not know what the problem is with Vegas 21. (Note - The original source of the linked clip was digitized Super 8 film.)

https://drive.google.com/file/d/18aCa9fNm5JFnJzeuTUDdQbN1yN2DCdzK/view?usp=sharing

That video event opens without a problem in Vegas Pro 22 ... but it shows as being MP4 AVC - which is fine.

Maybe try resetting VP21 back to its default (factory) settings - https://www.vegascreativesoftware.info/us/forum/faq-how-can-i-reset-vegas-pro-to-default-settings--104646/ - to see if that fixes the problem.

EDIT: It also opens here without an issue in Vegas Pro 21.

On my laptop also no problem to load and play that short event in VPro 21 with default settings, look

V20, V21 and V22 open this clip with no issues. Must be problem with Bob-H's system or Vegas installation.

I'd also do a reset of VEGAS.

No problem here with Vegas Pro 21-315.

@Bob_H said: "I converted many MPG files into MP4"

That step is likely a complete waste of time and energy since Vegas usually handles MPEG just fine and doing so injects generation loss from using a lossy codec, AVC.

Before converting the MPG files to MP4 using Vegas 19,

@Bob_H

That just might be the 10,000 pound elephant in the room.

I'll get back to you on this one, Bob.

You may choose to post a full file history next time around . . .

;?)

I don't see an elephant in the room? Irrespective of the full file history Bob has a problem with mp4 files that don't appear abnormal and which other forum members, including myself, have no problems importing into VP21.

I've many mp4 files created from SD vob, mpg and DV-AVI files. I've no problems with them.

It has nothing to do with the files but something appears wrong with this installation of VEGAS hence it makes sense to try a reset.

VEGAS should be able to import anything it can export (whether it's a waste of time or loses quality is a separate matter).

Ok guys (at least I think you are all guys).

1. I reset Vegas 21 back to its default settings and cleared the cache, but still cannot import an MP4 file.

2. I uninstalled Vegas 21 from my computer and reloaded the program from the Magix website. After that, I still could not import an MP4 file.

3. I reset Vegas 21 once again to default settings and cleared the cache, but still could not import an MP4 file.

4. I then tried to import other video files that I have on my computer. I was able to import AVI, MTS, MOV and MPG files with no problems. After that I tried to import numerous miscellaneous MP4 files I have stored on my computer and had the same problem no matter where the file came from. I am though able to open and view any of the MP4 files on my computer using Media Player, Movie Maker, Movies & TV, Photos, and VLC Media Player.

I'm lost and have run out of things to try.

@Bob_H I'd try official support then as those are the obvious things to do. Scroll back up to the top and click "support."

@Bob_H Another thought. Have you installed any codec packs such as K-Lite?

I do not remember installing any codecs. If I did, it was more than a couple of years ago.

Bob, I had no problem opening your sample MP4 in Vegas Pro 21, 20, and 18.

I suggest Resetting Vegas to Default Values, a good first step for troubleshooting.

Once you have that resolved, go ahead and upload your original MPEG source clip, and we can help you with processing DVD source door-to-door in Vegas, at least with pulldown removal and luminance levels.

I have contacted technical support. If I am able to get a solution from them, I will post it here.

PS. There is no preference for "Enable Legacy AVC & HEVC decoding" in my version 21 software.