Hi everyone I was searching online for my problem and ran across your forum, I hope you don't mind me stopping by to ask a question.

Basically I have 2 files, an mp4 video file with no audio and an aac audio file that corresponds to the video. What I want is to make so that they are just one mp4 file. This way it will be compatible with any program I want to play it in. I can sorta do it now, but all the programs I try to do it in want to compress/convert my video file again. Is there anyway to just add the audio "back" to the video?

Thanks a million,
Jack

I'm not the brightest light here but my answer is:

You have two files you want to combine. To combine two files into a single composite file you must render or process the two to achieve one.

If you have decent eye and hand coordination you can do this simply and quickly with most any consumer editing program - one example is ULead Video Studio and there is a free download trial version available.

Simple steps but it can be tricky.

Open the video in main timeline of the workspace of the program.

Open the audio clip in the associated sound timeline.

Now the tricky part but I have done this many, many times. Find a visual cue at the beginning of the video that you KNOW for sure what the sound for it is on the audio.

Then you have to adjust the visual cue to match up with the associated sound cue. As you experiment you play both clips. In a few attempts you will move the sound so it is heard at the same moment as the visual cue.

Once both play together and appear in sync then you render or complete the project and the result will be a combination of video and audio.

If you begin with a mp4 type file and process the edited result out as a mp4 I doubt you will suffer much visual loss in the one step process but to combine files into a single melded file you must process or render once you have them in sync.
goodluck

I was able to combine a video and an audio using windows moviemaker. i have been using it to make a couple of video projects for school and it has been quite successful. it's really easy to use too and I didn't have to download anything.

While the above solutions will no doubt give you a file with both streams, what you really need is an MP4 multiplexer. There is one downloadable from here:

MP4Box

This is a command-line tool, although a GUI add-on also seems to be available. I have no idea of its performance since I haven't used it. Give it a shot and report back here if it's any good. There may be others interested.

For your problem the Watermark Master can be very simply used,
simple run and use Wizard for help!

http://www.videocharge.com/Index.php