FFMPEG: How do I join multiple videos into 25GB chunks?

[slax65]

Hi guys,

so while I'm using BluRay Discs as a backup method in addition to a HDD, I have a question:

How do I merge/join multiple smaller MP4 files into 25GB chunks in order to use all free space on a BluRay disc?

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Let's say I've got four files: file1.mp4 (2.0GB), file2.mp4 (18.0GB), file3.mp4 (8.0GB), file4.mp4 (5.GB)

The result should look like this:

video1.mp4 (= file1.mp4 (2.0GB) + file2.mp4 (18.0GB) + file3.mp4 (5.0GB ...)
video2.mp4 (= file3.mp4 (... 3.0GB) + file4.mp4 (5.0GB)
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I think FFMPEG should do the job but someone has to help me with the commands.

[pandy]

https://trac.ffmpeg.org/wiki/Concatenate

[Cornucopia]

If those various mp4 files are dissimilar in their resolution or framerate (or a few other things), you either won't be able to concatenate them at all, or you could squeak by but the result would likely wreak havoc with players trying to read them.

If you are trying to make them playable in std. hardware players, you should load them in as sources in a true BD authoring app. If they fit or don't, it should tell you. It may also let you know if it can or cannot concatenate (and it may not be necessary if the app can put them together as separate titles, not "chapters").
If all you are doing is using the BD as a data backup disc, no need to concatenate anything! Just create a playlist.

Scott

[slax65]

They are native files from a camcorder. I just burn them on a data-BluRay disc. It's just to make assurance doubly sure in case my HDD breaks for some reason. In this case I have the BluRays still. It takes way more time to burn them instead of saving them to a HDD but than again I haven't been filming that much lately.

It's just that while all files have a different lenght and so different sizes it's never possible to fully use the 25GB on a Blu Ray. I could also pack all the videos into a rar file that is split every 25GB but this takes even longer and errors can occur with the rar files.

So is it possible to join all my camcorder's videos into 25GB chunks?

[transporterfan]

How would you separate them or index them? Surely, it's better to archive them on BD data discs with ImgBurn?
Yes, it's possible to make them exactly 25GB. Just zip file them all and split with HjSplit, but it will mean joining the split files together in order to simply unpack an archive.
The BD data disc options seems the better solution.

[Cornucopia]

If they are all from the same camcorder with the same/similar settings, then I would say YES.

Personally, I do not recommend raw binary file joiners, due to the extra overhead & the non-standard syntax that results. Better to use a remuxing concatenator like possible with ffmpeg. Yamb/mp4box or similar should also be able to do it.
But you said it yourself: it isn't possible to get right up to just shy of 25GB, without splitting some titles. Even with concatenators. And at that point, it makes more sense to put them in an NLE that supports smart rendering, to make them legit. Rar, etc., are both inefficient (highly compressed files often grow inside them) and time-consuming for video files, requiring extra steps to extract & often even preview.
My recommendation is that if you HAVE to utilize every available space, then go to the effort of using a smart renderer. Else, skip all this BS and buy a few extra discs and just put on what you can easily fit at the time, knowing that sometimes/mosttimes it won't be 100% filling capacity.

Scott

[transporterfan]

https://sourceforge.net/projects/discfit/

Calculates the most efficient way to pack folders and files over a span of discs.
Might be useful to you.