solving aspect ratio problems

Need to correct a video with an incorrect aspect ratio? With Movavi Video Converter, you can do it easily!

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Solving Aspect Ratio Problems

The most common problems

In previous articles, we have mentioned the most common problems associated with aspect ratio: when you play video on your DVD player, it appears stretched horizontally or vertically. Such problems can be easily solved by tweaking hardware settings – configuring the DVD player or TV set to the correct aspect ratio.

But what can you do if your video doesn't display correctly when you play it in a software media player, for example, if you have a video file that was converted with the wrong aspect ratio?

And there's one additional problem related to aspect ratio – one we often hear from our customers. How do you remove the black bars from the edges of the video?

With Movavi Video Converter, you can easily correct your stretched video so that it displays normally, and you can remove those unwanted black bars.

Problem classification

Let’s summarize the problems associated with aspect ratio described above:

  1. The video has an incorrect aspect ratio and appears stretched
    • a. vertically (all objects look narrow and elongated)
    • b. horizontally (all objects look flattened out)
  2. The video has the correct aspect ratio and is not stretched, but has black bars
    • a. across the top and bottom
    • b. down the left and right sides

Solutions

  1. Correcting stretched video.
    • a. In most cases, this occurs because a widescreen (16:9) video was stretched to a 4:3 aspect ratio, breaking the original aspect ratio. To correct this, we need to stretch the video horizontally while leaving the height unchanged (see Figure 1). Stretching incorrectly converted video back to 16:9

      Figure 1: Stretching incorrectly converted video to 16:9

      Knowing the height of the converted video, we need to calculate its width. Let’s use W as the width of the, and H as the height.
      The converted video is supposed to be 16:9, i.e. W:H = 16:9, so the width should be calculated as W=16×H:9.

    • b. It appears that a 4:3 video was stretched to 16:9, breaking the original aspect ratio. To correct this, we need to compress the video horizontally while leaving the height unchanged (see Figure 2). Stretching incorrectly converted video back to 4:3

      Figure 2: Compressing incorrectly converted video to 4:3

      The converted video is supposed to be 4:3, i.e. W:H = 4:3, so the width should be calculated as W=4×H:3.

  2. Removing black bars.
    • a. This usually happens when a widescreen video (16:9) is converted to 4:3 using the Letter Box resize method. You can find more information about resize methods here. The proportions of the image are fine, but black bars have appeared on the top and bottom of the video. The result can be very distracting when you watch the video on a widescreen TV, as it adds its own bars to the sides of the video to display it on the screen. This is called windowboxing or postage stamp effect and your video will look like Figure 3:

      Windowboxing

      Figure 3: Windowboxing (postage stamp effect)

      You can remove the bars and return the video to the 16:9 aspect ratio using Crop resize. We need to crop the video vertically while leaving the width unchanged (see Figure 4).

      Cropping letterboxed video back to 16:9

      Figure 4: Cropping letterboxed video back to 16:9

      Since the converted video is supposed to be 16:9, i.e. W:H = 16:9, the height should be calculated as H=9×W:16.

    • b. It appears a 4:3 video was converted to 16:9 using the Letter Box resize method. In this case, black bars are added on the left and right sides of the video image. You can remove the bars and return the video to 4:3 aspect ratio by using the Crop resize method.
      We need to crop the video horizontally while leaving the height unchanged (see Figure 5).

      Cropping letterboxed video back to 4:3

      Figure 5: Cropping letterboxed video to 4:3

      The converted video is supposed to be 4:3, i.e. W:H = 4:3, so the width should be calculated as W=4×H:3.

Conversion instructions

To convert a problem video file, follow these steps:

  1. Add your video to Movavi Video Converter and select the appropriate output preset from the Convert to list.
  2. Click the Settings button next to the Convert to list.
  3. Open the Frame size list and select the resolution that you've calculated above. If you want to set it manually, pick the Custom item and enter your width and height values into the corresponding fields.
  4. Select from the Resize method list:
    • Stretch if you want to correct stretched video
    • Crop if you want to remove black bars from the edges of your video
  5. Click OK.
  6. Convert the video.

See what else Movavi Video Converter can do for you:

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