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By Jordi D. Rodríguez - Contact Author

How to Change Aspect Ratio of a Video on Windows/Mac

The aspect ratio of a video simply means the proportion between its width and height. The most popular options are 4:3 for standard TV (NTSC/PAL) display and non-widescreen computer displays, and 16:9 for widescreen (HD) TV displays (1080p, 1080i, 720p etc), and 4K-capable displays, and surely there are more. But it defines how the video looks like in the video player and other applications, and this is why we should change the aspect ratio of a video on some occasions.

We will talk more about this later in this post, but now the real question is how to do it. Don't worry though, because, in the next part, we will show you the detailed steps to change aspect ratio. Keep reading.

How to Change Aspect Ratio of a Video on Windows/Mac

In this guide, we sincerely introduce the aspect ratio converter - VideoProc, which is a useful and basic video editing application running on both Windows and Mac, to make this job much easier.

Why We Recommend VideoProc?

1. VideoProc does not change aspect ratio by copping. There will be no images being cut.

2. It has the complete profiles for aspect ratio, 16:9, 9:16, 1:1, 4:3, 4:5, 2:1, 2:3, etc.

3. Super fast converting speed. Since VideoProc supports Level-3 Hardware Acceleration, it will make the converting speed 47x real-time faster, but with low CPU usage.

4. Besides, aspect ratio converting feature, VideoProc also supports many other advanced video editing functions, such as resolutions changing, frame rate adjusting, cut, split, rotate, denoise, deshake, merge, and more.

With VideoProc, you can change the aspect ratio without worry. So why not download it now and follow the detailed steps below to make your job done?

Here are the detailed steps to change the aspect ratio of a video

Step 1: Run VideoProc on your computer, and then choose the Video option.

choose video option on VideoProc

Step 2: Click + Video button to import the video which you plan to change its aspect ratio; Then it will be displayed in the middle part, and now you need to choose the video output format that you prefer; Lastly, choose the Codec Option which is located at the right corner of the video info bar.

import video on VideoProc

Step 3: Find the Aspect Ratio option, select the aspect ratio you prefer by unfolding the options, and click Done Button to get back to the next page. You can also check the Expand Video box right above the Aspect Ratio option, which will shrink or enlarge the image by adding letterbox to help the image fill the full screen when necessary. This will remain the original image undistorted.

change aspect ratio parameter on VideoProc

Step 4: Toggle the Hardware Acceleration Engine option to enable fast conversion speed, choose the output folder so you can easily find the file after converting, and then click the RUN button to start.

check hardware acceleration and output folder

Why Change the Video Aspect Ratio?

We know that before the days of HD televisions, almost all videos follow the aspect ratio of 4:3 as the standard, but now it changes to 16:9. And not just the televisions, many screens of computer and other devices are 16:9. So when we play the 4:3 videos on them again, there are many players which do not support them and suggest you change their aspect ratio.

Or even though most of the video players support playing those videos, however, there would be the issue of black bars occurring; This is not good for the video watching, and to fix it, we need convert the aspect ratio to the one as same as the screen.

Surely, there are some improved media players to enable us to change the video aspect ratio, even the 9:16 video shot by a mobile phone. But it is just temporary.

There is also another situation where you may face up with the video aspect ratio converting, ie: the social sharing. For example, Instagram only supports square videos (1:1). So let's say when we shoot a vertical and lovely video with your iPhone and want to upload it to our Instagram account to share with our friends. Well, we need first to change its aspect ratio for the next operations.

Surely, there may be more situations requiring the video aspect ratio converting.

Why Not Recommend the Built-in Tools on Windows/Mac for Video Aspect Ratio Converting?

On Windows, we know that the Windows Media Player is mainly responsible for our video playing or some other operations. But on Windows 10, we did not find its aspect ratio changing feature. And based on the discussions on the related forums, there seems no answer.

But on Mac, the job can be done with one of its built-in tools. You must have guessed its name - iMovie. However, before you apply the iMovie for aspect ratio converting, there are a couple of things we need to tell you,

  1. iMovie changes the aspect ratio simply by "Crop". When we crop a video, it means cutting off some pictures on both sides or top/bottom borders. Obviously, it will lead to image loss.
  2. Since iMovie changes the aspect ratio by crop, it doesn't provide the specific aspect ratio options. There will no specific 16:9, 9:16, 4:3, 1:1, 4:5, or more option for you to choose.

So considering such problems that you may encounter when you use the built-in tools on Windows/Mac, we suggested you use VideoProc to finish this job above.

The Bottom Line

As you see, it will become very easy to change the aspect ratio of a video with VideoProc. There just need 4 steps. Why not download it now, get your job done in minutes, and explore more fun features in VideoProc?

Besides, if you want to learn more video editing tricks and tips, you can follow us on Facebook or Twitter, where you can also tell us the problems about video editing that you cannot fix or your words about our product.


Jordi D. Rodríguez

Jordi was an amateur tech enthusiast, but now an editor who has published hundreds of stories covering hardware acceleration, video editing, software review and how-to guides. He is more like a "tech support" with adventurous soul, eagerly grabbing cutting-edge video technologies off in a professional yet easy-to-understand style, and enjoying gliding, diving, etc.

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