Compress and merge two video files

I used a JVC hard disk drive camcorder to record a roughly two-hour event. Because the camcorder documentation states that it can record over seven hours on its highest quality setting, I used that setting. Afterward, I discovered that it split the video into two files. One file is about four gigabytes, and one is about two gigabytes. So now I have two problems. The first is that I have to join (merge) the files into one. The second is that I have to compress the resulting file enough to fit on a single DVD. Or maybe I need to compress each file first then merge them. Either way, I’m having no luck. The camera put the files into .mod format. I can change the extension to mpg or add .mpg to the .mod extension and the videos will play in Real Player and Windows Media Player, but I can’t compress or merge the files.
My goal is a single video file on a single 4.7 GB DVD. Any help will be greatly appreciated. I’m willing to buy software online if freeware apps won’t do what I need, but I don’t want to pay for the wrong applications, so any guidance in that department will also be appreciated.

Please help.

If you don’t get any joy here, try the A/V section of the forums at

What DVD authoring software do you use? Nero can handle this pretty trivially, but there’s not point spelling it out if that’s not what you use.

As I understand it, .mod files are a form of mpeg2 file and that you can just change the extension. I’m always wary of just doing that as I assume there must be some difference, which will give problems later.

However, assuming you end up with a couple of mpeg2 files, firstly you want to join. I have found that there are any number of little freeware mpeg joiner programs out there. Be careful. Most of them are crap!. They just join the files together bodily, with no attempt to properly fix up the timecode and you will end up with problems down the track.

The best programs I have found for mpeg2 editing, joining etc are those sold by They range from the basic (MPEG2VCR) to the more sophisticated. They all are available in full working versions on trial for 30 days. The more sophisticated programs are easier to use, but MPEG2VCR will do what you want, but you may have to fiddle about a bit to figure out how to do what you need to do (the help is pretty crap).

However, when you join MPEG2’s using Womble’s products you get a proper single file, without introducing errors at the join. Also, unlike basically every other converter I’ve come across, Womble’s products do this while only re-encoding at the join, and without re-encoding the whole damn thing. This means faster processing, and no loss in quality.

I haven’t tried the compression settings in Womble’s products, but I’m pretty sure you’ll find they will do what you need there also.

There are loads of really great video manipulation utilities out there for free - check out the tools section of

Often with jobs like this - if you’re using freeware - it’s necessary to use more than one utility to achieve the desired result, but in this particular case, I’m almost certain DVDShrink will do the whole thing - certainly it will intelligently recompress the file to fit whatever size limit you specify - Using it in ‘File Mode’ should enable it to see two different VOB or MPG files that you have copied into the same folder on your hard drive, then ‘re-author’ them into a single DVD, but if not, there’s another utility that will easily merge the files before you start (but I can’t remember what it’s called, as it’s on my home PC and I’m not at home now - I’ll post back later)

And you probably thought of this, but make copies of the 2 files and mess with the copies so you don’t ruin the originals completely.

Thank you for the help! I’m going to try again, today. I had already tried some utilities I found on the Internet without any luck. MPEG Joiner, for instance, said “Done!” half a second after I clicked “Merge,” but the resulting file was zero bytes. I was ready to give up, but now I have hope again. and DVDShrink here I come!
Again, thank you.

Mpegjoiner is one of the pieces of total dreck I tried before I managed to find an explanation by someone knowledgeable. It just does a simple butt join of files. As I understand it, the MPEG2 format is not so simple that this works, reliably.

If the files are sufficiently similar in structure (which has a fair chance of being the case if they were both encoded by the same camcorder using the same settings), then joining them together should be fairly straightforward.

I think the software I use (as mentioned above) is VOBMerge

I was trying to join several files off the same digital video camera, shot moments apart with no change in settings and I was still having problems. The result would play on some players but not others. On others when it reached the join it would lock up, or play only sound and not video, or pause then go on, or the sound and video would lose synch.

Even on the players where it would play right through, I’d notice that the player would report the video as being shorter than it actually was - presumably because it was reading a header at the beginning of the file that hadn’t been corrected when more video was added at the end.

Hmmm… Actually, on thinking about it, the only files I’ve ever successfully joined simply would be those that started out on the same physical disk - either because they began as different title sets on a DVD, or because they were different recording sessions from a DVD recorder, but again, onto the same media - I expect something about that had prejudiced the files to be compatible for simpler joining.

It could be that or you could have been lucky. I went through a couple of free simple joiner programs and most of them produced a joined file that would work on at least some players/editors.

I’ve always used TMPGEnc to join or encode mpg files. It’s been a long time since I’ve used it though. I think it has a 30 day free trial. It also allows you to choose a file size or bit rate when encoding.

A small utility named GSpot will give you all the codec information you need about your files.