The free audio editing software Audacity can do that, and a lot more. For the purpose of this tutorial I’m going to stick to the basics.

Download Audacity from the developer website.

Start Audacity after installation. You can drag and drop audio files like mp3 or wav into the program interface, or use the File > Open dialog to do that. Files that you drag and drop into the interface appear in the same window, audio files that you load via File > Open appear in their own windows.

To merge two music files that you have added to Audacity do the following: Select one of the tracks with a left-click and press Ctrl-A afterwards to select all of it. You can alternatively select only part of the track. I suggest you use the play button to pinpoint the start and end locations of the track.

With the track in the clipboard left click on the location of the other track where you want to paste your music into. If you just want to merge, click the position at the very end of the track and press Ctrl-V to add the music there. You can select any other position if you prefer that.

Repeat that process until you have have all audio files merged in one track. Close all but this one track before selecting File > Export to save the newly merged audio file. You can save the audio as mp3, wav, flac, ac3 and several other formats.

Is there an easier way to merge multiple mp3 files and save them as a single audio wav file? Let me know in the comments.

Today I’m going to demonstrate how to change the video speed in VirtualDub. This can be handy in certain situations, for instance if you want to speed up part or all of a video, or slow down part or all instead.

You do need a recent version of the VirtualDub software which you can download from the developer website.

Start the software and load your video, or videos, with a click on File > Open Video File, and File > Append Avi Segment.

Please note that changing the speed of a video has an effect on the audio. The audio will get out of sync, and it is usually the best option to replace the audio afterwards with a new track. Besides, it would not make lots of sense to slow down or speed up the audio anyway, now would it? You can add another audio track under Audio > Audio from another file.

Click on Video > Frame Rate or press Ctrl-R to open the menu. Most videos have a default frame rate of 25 or 29.33. All you need to do know is to change that framerate to speed up the video or slow it down. If you want the video to slow down, you need to decrease the frame rate, and vice verse if you want to speed it up.

A framerate of 50 would effectively double the playback speed of a 25 FPS video while a framerate of 12.5 would half it. VirtualDub displays the current video framerate in its interface which you can use to calculate the new framerate.

Click ok in the configuration window. I recommend to preview the output before you make the conversion. Click File > Preview Output from start to do that. The video plays in the new speed in the VirtualDub window.

If you are not satisfied with the speed change it again under Video > Frame Rate. Repeat that process until you are satisfied with the new video speed. You can then save the modified video under File > Save As Avi.

And that’s how you change a video’s speed using VirtualDub.

VirtualDub is a portable software, which means that you can run it from anywhere without installation. Start by loading your video into the software. This is done via File > Open Video File. I suggest you check both the Video and Audio menus to make sure that Direct Stream Copy is enabled. This speeds up the splitting considerably.

Select the beginning frame of the first part of the movie. This is done with a click on the frame bar at the bottom of the screen. If you want it to begin at the first frame, do nothing and select Edit > Set Selection Start. Now switch to the end frame for the first part of the video. For my purpose, I selected it to be around 14:30 minutes in. You set the end frame under Edit > Set Selection End. All selected frames should now be highlighted on the frame bar.

To save the part of the movie select File > Save Avi As from the menu. This saves only the selection that you have made. Make sure you pick a different file name. Once the part has been saved select Edit > Set Selection Start again, and move the position to the end of that part of the video. Repeat the process until you have segmented and saved the video.

Some users may want to automate that process. They can do so under File > Save Segmented Avi. Here they can limit the number of video frames per segment, and / or the file segment size limit.

It is not possible to segment by playing time directly, but you could use the frames limitation option for that. You may need to link specific frame rates to times though, which you can do in the main interface. Just click on the frame bar to check frames and playing times to get the right frame count for each part.

Users who want to split videos or movies can download the latest version of VirtualDub from the developer website.

Download the latest version of VirtualDub from the official website. Unpack the portable software to your hard drive after download, and run the VirtualDub.exe afterwards.

You load the first movie with a click on File > Open Video File. Click on File again and select Append Avi Segment for each additional part that you have as a file on your hard drive. You can only load one movie at a time, which makes the process somewhat unhandy if you have many different parts.

Switch to the Video menu and make sure Full Processing Mode is selected there. Click on Compression under Video afterwards, and select one of the available video codecs. Please note that you need suitable codecs installed on your system for a solid result that offers a good image quality and suitable file size.

You can furthermore add filters to the process, for instance if you would like to resize the video, change the brightness and contrast or add a logo to one of the corners. You can preview the changes by pressing enter or by selecting File > Preview Filtered.

Once you have made your selection select File > Save as Avi and pick a directory on the local hard drive to save the video to.

VirtualDub will display a status window where you can get information about the current processing status, as well as an estimation of the file size of the new video file. You can jack up the process priority if your computer is idle otherwise.

And that’s it. Just wait for the process to finish. It is recommended to play the video once on your hard drive to make sure that the merging was successful and without errors like out of sync audio.

Then you need to correct the out of sync audio before you burn the video to DVD. If you do not chance is high that viewing the video DVD will not be a pleasure at all, considering that most hardware DVD players do not have options to correct audio that is not synchronous to the video.

One of the best programs to correct out of sync audio is VirtualDub. Downside is that it may not work with all video formats, and that you may need to install a codec to work with a specific video format in the program.

The process itself is however dead easy, provided that you know the exact milliseconds that the audio is playing to early or to late.

Load the video into VirtualDub after installation. You do that with a click on File and the selection of Open Video File from the menu. If you get an error that a codec is missing you need to install an appropriate codec for the video format before you can correct the audio discrepancy. This is usually the case when you use a video player like VLC or MPlayer which come with their own binary codecs that cannot be used system-wide.

Make sure Direct Stream Copy is selected under Video and Audio in the menu bar. Now select Audio > Interleaving. You should see the following screen.

Locate the Delay audio track by setting and enter the time in milliseconds that is needed to synchronize the audio with the video. Enter a positive number to delay the audio track, or a negative number to start the audio track earlier.

I suggest you use a program like VLC to find out the exact time in milliseconds that that audio is out of sync. It usually takes to long to use VirtualDub to find that out.

Click OK afterwards to close the configuration screen again. Now select File > Save as Avi to save the video with corrected audio to the local system.

And that’s it. You have correct out of sync audio of a video file which can now be burned to video DVD.

You do need the program Virtualdub, a video file and some sort of audio file. Now start Virtualdub and either open the video using the File > Open Video File dialog or drag and drop it into the program interface. The video can be played right away in the software. You see it twice because the left one is the original video and the right one the processed video. If you only change the audio they will look alike.

Click on Video and make sure Full Processing Mode is activated. Switch to the Audio menu and make sure Direct Stream Copy is active in here. Select the Audio from other file option and pick a audio file on your hard drive. It will be automatically integrated in your video and play in normal speed.

Hit the play button at the bottom to see the video and listen to your audio. It should be in sync. If you are satisfied with the result you can select a compression for the video in the Video > Compression menu and save the video afterwards in File > Save as Avi.

Normally the music will not have the same length as the video and you could sync both by adjusting the frame rate of the video. Click on Video > Frame Rate. Notice the Change so Video and Audio Durations Match ? If you select that option the audio and video will have the same playtime. This means however that the frame rate of the video will either be increased (if the audio is shorter) or decreased (if the audio is longer).

So your video will either play faster or slower depending on your selection. A good tip is to convert the fps to the original fps as well in the same menu. I try to find audio files that roughly have the same length as the video to avoid slow or super fast videos.

The following method makes it possible to join multiple video files into one big file making it that much easier in the end to play and enjoy the downloaded movie. The method is different depending on the type of movie that you are playing. If the movie consists of multiple mpg movies you can use the windows command line to merge them.

Start the command line by pressing the windows key and R. Enter cmd in the prompt which will start the command line window. Enter the following line into the command line, make sure you enter the right filepath to the movie. I suggest you move the files to the top of a hard drive to ease the amount of typing that needs to be done.

copy /B “C:\movie1.mpg” + “C:\movie2.mpg” + “C:\movie3.mpg” “C:\completemovie.mpg”

This joins movie1.mpg, movie2.mpg and movie3.mpg into completemovie.mpg. You can add more movies to join more parts without problems.

You need an additional programs if the parts are avi files instead of mpg. Download the freeware VirtualDubMod and unpack it to your hard drive. Run the tool and select File, Open Video File and browse to the first part of the movie. Select no If a popup named VBR audio stream detected appears.

Click on File, append Segment and browse to the second part of the movie. Once this is done click on File, Save As and save the newly merged movie file to your hard drive.