In the past weeks, I have started to work with the video editing software VirtualDub to prepare videos before uploading them to the video hosting site YouTube. I learned a lot in that time, and have already passed some of that knowledge on in form of guides here on Ghacks. I have written guides about splitting videos and merging avi videos in Virtualdub.
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.Advertisement
Ghacks is a technology news blog that was founded in 2005 by Martin Brinkmann. It has since then become one of the most popular tech news sites on the Internet with five authors and regular contributions from freelance writers.