How To Save Certain Videos To Open Properly With Avidemux

Avidemux is a wonderful free open-cource program which has simple editing and offers many different filters for processing video (similar to Virtualdub for those that have used that). One problem that has arisen in the program however is that importing a few formats (such as FLV (Flash Video) files) results in what seems like only the upper left corner of the video being opened, and Avidemux 'sees' the video as being only 320x240. This post is how to change your video you want to work with to make it 'be seen' properly by Avidemux.

In our example for this post, we have an .FLV video file - which is just the type of container - that has an AVC H.264 format video inside of the container, with a resolution of 856x480 with a display ratio of 16:9 (perhaps a home video from YouTube or a family member). It is a widescreen video. When importing it into Avidemux however, it brings up only what seems like the upper left portion of that video and it looks square in the preview in Avidemux. 

This does not happen with all FLV containers or all formats of video, this is just an example, but for those whom this applies to, what is happening is that Avidemux is not getting the proper information from the video file to open it correctly.


To fix this takes only two steps using completely free programs:

1. You can demux (demultiplex, separate) the video and audio with a little utility called "FLV Extract" 
2. After that, simply re-mux (re-multiplex, put together) the video and audio in a utility called "YAMB"

To do this, just drag the video on to the first program, which opens up a little window to mouse-drag your file onto.

Then in YAMB, click ADD, and select the audio and video from the original clip (the files that flvextract makes, ending in .264 and .aac, which are the video and audio parts). Hit MUX and it will join them together in a new .MP4 file.

This file can then be read "properly".

That's it! Now those problem videos can be opened with these applications. Enjoy.

If I may suggest another great freeware program to open those 'trouble' video clips, I like to use Xmedia Recode. A list of the multitude of formats that the utility can handle, from the author's website, is here. As you can see, it is able to convert almost anything you will encounter into almost anything else, spectacular for a freeware program. Kudos to the author (although he is German, don't worry the program is available in English). I have used Xmedia Recode to open many .FLV and other files that Avidemux seems to have trouble with. I hope this help you a lot in working with your problem videos.

 Addendum:  Note that some video clips will sometimes result in having their video and audio 'out of sync' with each other (the audio seems to happen too early or late for the video occurences on screen, such as a gun shot appearing and then hearing the bang a second later) using the FLVextract/YAMB steps above. This is being investigated by many people and hopefully a fix for some of these problem videos comes soon. Until then, for these special problem videos, changing the frame rate can help with this problem. Whether in an editor or with another utility (such as AVI Frame Rate Changer), changing the frame rate slightly can help to put the video and audio back into syncronization. A tutorial post on this to come in the future! 
(Also, other video editing and conversion applications (such as Virtualdub and especially Xmedia Recode can open those videos without problem, so that they can be processed as desired, or at least converted into a format that your desired applications can import comfortably (such as de-compressing the video into an uncompressed or lightly compressed format, as in this article at this website) - when all else fails, try something else!) Good luck with it and I hope this has at least helped.

 

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