combine mp4 files

If all you want to do is tack the second video on to the end of the first, you can use the supplied QuickTime Player to do that.

Open the first video. From the menu, choose Edit > Add Clip to End. The second video will be placed directly behind the first. Click the Done button.

Save the concatenated file to a new name.

Hmmmm... Okay, maybe it won't do what I had hoped it would do. Sorry.

You can use iMovie but of course it will re-code everything with quality loss.

I'm afraid I still use Mavericks OS with a bunch of older software so anything else I might suggest will probably have the same issue.

I don't think it should be larger, or at least not much larger. When I last did this (uh, 5 years ago?) it created a .mov file which you could either have just as a pointer to the other files and was pretty small, or you could have as self-contained in which case it was just marginally larger than the source files. However, it was a .mov file which meant it wasn't universally accepted.

@Kurt @David Sloan1 @Limnos

I recently wanted to join some .mp4 files but had an extra problem. First some points relevant to the original query.

Kurt's suggestion looks a good starting point. As mentioned by Limnos QuickTime Player always very annoyingly saves the result as a .mov instead of the original .mp4 format.

There are a lot of online and free .mov to .mp4 conversion tools/sites. I am sure there are also local native Mac tools to do the same.

In my case I tried MPEGStreamClip and mp4joiner (both command line and GUI) and as it happens QuickTime 7 but all of them choked and rejected the mp4 files I was working with even though QuickTime Player X accepted them. (I could tell they had been produced using Handbrake.)

For the benefit of David mp4joiner is basically working in a similar manner to the cat approach but it should redo the headers unlike the cat approach. So assuming it works the resulting file size should be effectively the total of the individual files and it does not re-encode so it should be very quick.

In my own case I will try Kurt's suggestion and then converting the mov file. Otherwise I am going to have to re-encode my files. :(

With regards to the future of MPEGStreamClip it does not look like it will be updated. Even if it was made 64-bit Apple are killing off all the old QuickTime APIs in macOS 10.15 due out later this year. Your best bet is either to keep an old Mac (or Windows) to run it or create a virtual machine with an older Mac operating system.

Hi John,

I keep forgetting the limited choices in the new QuickTime. Yes, it will only export a .mov file. I'm thinking of QuickTime 7 Pro. There you copy/paste one open file into the other, then do an export. You have all kinds of format choices, including MPEG-4.

Problem is, like the current QT, it's incredibly slow doing the export. It must be re-encoding the entire sequence instead of simply saving it as is. Which it should do since I'm already starting the two .mp4 files. All it needs to do is concatenate the two as a new file. But doing a bit of searching on that just now, QT will always re-encode the joined video.

I tried using the cat command in Terminal, and it went very fast. Started with two video clips about 370 MB each in size, and ended up with a 730 MB output. Except, instead of a roughly 42 minute video, I got a file that was still only the first clip at about 20 minutes. Since an MP4 is a container file, the second video clip is likely in there (accounting for the output size), but the second video is not connected to the first, so is just taking up space.

All kinds of suggestions can be found to use iMove, and lots of other third party apps. But all seem to require doing a re-encode to the final combined video.

Have you tried Format Factory? According to this 3-minute video, it will join video files without re-coding. The comments show people have had success with it, so may be worth checking out. https://www.youtube.com/watch?v=05Vpt-S-Ds4

I had to do a bit of a double take on it myself. If you search for Format Factory for Mac, then you get all kinds of links for an "alternative" to Format Factory. I didn't try one of these supposedly similar apps to see how well they work.

Yeah, that's what I did and saw many links, but didn't click through... they all go on to say there isn't a Mac version, BUT.....

Anyway, if Format Factory does precisely what David wants, and he has to do his process all the time, it may be worth getting a cheap/used Windows box, or run an emulator.

One other idea: there are online services that can join video files like this one. Even if it has to recode the files, it would be using the online service's processor and run as a background service, freeing up David's computer to do other work.

Subler.

How about loading them both into iMovie and exporting the combined product as an MP4? You probably already have the software, or you can download it for free. This would be a fast and easy solution.