The most common video aspect ratios are 4:3 (1.3:1) and 16:9 (1.78:1). The former is the standard TV format, while the latter is the latest widescreen TV format. Besides these two, 21:9 is also popular. As far as you may know, many media players enable you to change the aspect ratio in real time. Yet the change is temporary. Next time you open it, you need to make changes again.
To change the aspect ratio permanently, you need a video editor or converter. Here I humbly recommend Wondershare Filmora (originally Wondershare Video Editor)(Windows 8 supported), which lets you create both 4:3 and 16:9 video for sharing on TV, computer, web and YouTube. This article will show you how to change aspect ratio step by step. Check it out.
Step 1 Choose an aspect ratio to get started
You should choose a target aspect ratio at the beginning. It depends on the aspect ratio of your media source. If most of your media source files are in 4:3 aspect ratios, you should select 4:3 standard aspect ratio. For you've select an aspect ratio, then the media files that are in 16:9 or other aspect ratio will be converted with black bar, and be stretched if necessary. This is the solution when aspect ratio discordance occurs. But if you just want to change aspect ratio of one video file, simply choose an aspect ratio and go.
Step 2 Import video files
Now import your video to change aspect ratio to the program by clicking the Import button or simply by dragging and dropping video files from File Explorer to the program's primary windows.
Optionally, you can edit and enhance your video with plenty of visual effects, titles and all common video editing tools.
Step 3 Change aspect ratio
Depending on your needs, you can either save your videos to computer for media player or mobile device, directly upload to YouTube, or burn to DVD for watching on standard or wide screen TV. To do so, click "Create" button when you are happy with your video.
Change aspect ratio for device
The default tab is "Device". You can save your video in formats that are compatible with all popular devices, including iPhone, iPod, iPad, PSP, etc. When you've chosen a device, all resolutions with optional aspect ratio will be given. Simply choose your favorite resolution from the list. The higher, the better video quality, but also larger file size.
Change aspect ratio for computer
Switch to "Format" to save video in specified aspect ratio to computer. Once a format is selected, all resolutions with different aspect ratios are available. Depending on the resolution, the output video aspect ratio is different. For example, 1280x720 is a 16:9 video, but 640x480 is a 4:3 video. You could calculate the aspect ratio yourself. Always change aspect ratio to the same with your choice at the beginning. Otherwise, black bars may be added.
Change aspect ratio for YouTube
Go to "YouTube" tab and type in your information before clicking the "Create" button. There is no need to select an aspect ratio for second time. Your videos will be directly uploaded to YouTube depending on your select at the beginning.
Change aspect ratio for TV
It's easy to switch aspect ratio for TV between 4:3 and 16:9. When you're in the "DVD" tab, you'll see an aspect ratio option. Simply choose what you want depending on your TV's screen.
What's Video Aspect Ratio
The term Aspect Ratio refers to the relationship between the width and height of a video, irrelevant to the actual physical size of the picture, however. Aspect ratio is expressed in the form of "width:height", for example, 4:3 and 16:9 which are the main video aspect ratio, a.k.a 1.3:1 and 1.78:1. Usually, you can change aspect ratio in a media player like VLC Media Player, but that's temporary change. You need a video editor for changing video aspect ratio like Wondershare Filmora (originally Wondershare Video Editor).