Resizing videos can be a lot more complicated than it appears. In particular it can be challenging to make sure the video quality looks good while at the same time you adjust its size to the dimensions that are required.
To help ensure that you’re able to resize your videos more effectively, there are three factors that you should always keep in mind:
- Aspect ratio
It is important that the very first factor you focus on is the aspect ratio. To be more specific you should look closely at the aspect ratio of the original video, and the target frame that you want to resize it to.
If the aspect ratios are different you will need to decide on how you want to resize the video to fit into the new aspect ratio. Although you could stretch it to fit, that will make your video look skewed and distorted which isn’t ideal.
Instead in most cases you would want to either crop the video or add black bars to letterbox or pillarbox it based on the new aspect ratio.
When you scale your video and increase or decrease its size, you will either be adding or removing pixels. To make sure the video still looks good its pixels will need to be resampled and interpolated.
The reason the interpolation that is used is an important factor is because it can have a big impact on the quality of the video. There are several types of interpolation that are used to scale videos: Nearest-neighbor, bilinear, bicubic, Lanczos, Spline, and more.
As a rule you should avoid using nearest-neighbor interpolation as its results tend to be poor. Generally bicubic is one of the better options, though Lanczos and Spline are often used too.
- Video bitrate
Always remember that when you resize a video you it will require a higher bitrate in order for its quality to be good. The exact bitrate that will be needed will also depend on the frame rate as well as the video format.
Some software may automatically adjust the bitrate when a video is resized. However that is often not the case, and if so you will need to make sure you set the export settings to use the right bitrate for your video.
Overall your goal should be to make sure the quality is good, and that there are no compression artifacts present.
If you don’t already know how to resize video, you should be able to learn fairly easy. It should be possible to resize videos in most video editing software, or if you prefer you could try the resize video web app for example.
Just be sure to keep the factors listed above in mind when you do resize your videos, and choose which options you wish to use accordingly. That could make a big difference to how your videos turn out after they’re resized and their overall quality should be much better.