Before I start with this tutorial please download VirtualDub from VirtualDub.org.
Many of us want to save just a small portion of a video, discard unwanted scenes from a video or add a logo of your choice to the video. Its very easy in virtual dub. First open the video in virtual dub. Virtual dub opens all kinds of video files with exception of the wmv and asf format as these are patented by microsoft. But you can find a version which opens asf too on doom9.org .
The bottom buttons are the controls for the video playback and editing. There are play, stop, forward, rewind, jump to last and first index, jump to previous and next key frames, scan for scene change and frame markers.
First of all a little knowledge on how video is compressed in the mpeg format. The video when uncompressed, stores each and every frame in the plain rgb(Red Green Blue) format. But there are many redundant frames in any sort of video which are viewable by us. The mpeg format truncates those duplicate frames and stores only the information on the pixels that changed from the previous frame to the next frame. The first frame is known as the key frame. But the scenes are all not redundant but change after some time totally. So when the scene changes, a new key frame is added to maintain the compressed size and quality of the video file.
Now the frame markers are used to select the no of frames which are to be deleted. Select the frames using the frame markers and the progress bar above the buttons. The mark in, mark out and the selected frames can be seen in the picture.
Press delete to delete the frames. You can follow the same procedure to delete all the unwanted frames. This comes in very handy when you need only a song from the entire movie.
Still the video needs saving. To save the video, there are two ways. First a direct stream copy and next the full processing in the video modes option. The former just copies the frames as it is to the new file excluding the ones you deleted but the latter requires for the compression format before save. Direct stream copy is not compatible with some formats and hence virtual dub might give you an error. In that case choose full processing mode and In this mode you can save it to any format you like. Choose the compression format before you save.
In this window you can also add the saving process to a batch job and can save multiple videos with the virtual dub's job control. Also you can break the video so that it fits on a cd and so on.
Virtual dub has a many plug ins which you can use to enhance your videos. They are available under filters. These filters can change your movie to black and white or can put a logo on the video which can be your own photo. Under video filters click on add and a window with all the inbuilt and added filter plug ins will be displayed.
When you choose a filter its configuration window will open after which the filter will be added to the list of added filters. The logo filter lets you display your own photo on top of the video. It asks for the image file for the image to displayed and the transparency and the screen justification can also be set from there. But the images are accepted only in the form of bmp and tga. If you don't have a picture in that format then you can use any existing image editing software to convert it into that format. Also don't forget to resize the image before you insert it, else the image may cover the screen with its size. Click on OK and save the video to get the job done.
You can experiment with the other filters and have fun.
There is one more cool thing that you can edit in a video. You can change the audio of the video file so that it plays your desired audio when you play the video. You can also choose to keep more than one sound track which is only supported in some formats. Windows media player can be used to choose between sound tracks when you view the video. To do this open up the stream list under audio menu and manipulate the sound tracks as you want. To disable the previous track click on disable and the audio will be deleted from the file. Use move up, move down to change the order of the tracks when you save multiple tracks. You can also extract the audio in the wav format by selecting the sound track and clicking demux. It will ask for a place to save the track and de multiplex the audio from the video to that location.
Always remember to save the video after you have edited it as by not doing so you will lose all the editing you have done.