About aspect ratios

An aspect ratio specifies the ratio of width to height. Video and still picture frames have a frame aspect ratio. The pixels that make up the frame have a pixel aspect ratio (sometimes referred to as PAR). Different video recording standards use different aspect ratios. For example, you record video for television in either a 4:3 or 16:9 frame aspect ratio. For more information, see Frame aspect ratio.

When a project is created in Premiere Pro, you set the frame and pixel aspect. Once these ratios are set, you cannot change them for that project. However, you can change the aspect ratio of a sequence. You can also use assets created with different aspect ratios in the project. 

Premiere Pro automatically tries to compensate for the pixel aspect ratio of source files. If an asset still appears distorted, you can manually specify its pixel aspect ratio. Reconcile pixel aspect ratios before reconciling frame aspect ratios, because an incorrect frame aspect ratio can result from a misinterpreted pixel aspect ratio.

Types of aspect ratios

Commonly used aspect ratios are:

Widescreen (16:9)

It is the standard aspect ratio commonly shared by online videos, documentaries, and films. It captures a large amount of data with details.

Widescreen (16:9)
Widescreen (16:9)

Vertical (9:16)

It is the video recorded on your phone.

Vertical (9:16)
Vertical (9:16)

Fullscreen (4:3)

It is the aspect ratio that was used on television before widescreen was used. It focused on a particular element at a time.

Fullscreen (4:3)
Fullscreen (4:3)

Square (1:1)

It is a perfect square ratio that is commonly used on Instagram.

Square (1:1)
Square (1:1)

Anamorphic (2.40:1)

It is a wide widescreen often used in movies. It is similar to 16:9 but the top and bottom are cropped. This effect gives it a cinematic feel.

Anamorphic (2.40:1)
Anamorphic (2.40:1)

Set the aspect ratio

To set the aspect ratio of a sequence, do the following:

  1. Create a new sequence. Select File > New > Sequence.

    For more information, see Create and change sequences.

  2. Go to the Settings tab of the New Sequence dialog box.

  3. Go to the Settings tab.

  4. Under Video, enter the Frame Size(height) and horizontal(width). Premiere Pro automatically generates the aspect ratio.

  5. Fill out the respective fields, name the sequence, and click OK.

The aspect ratio for the sequence has been set.

Frame aspect ratio

Frame aspect ratio describes the ratio of width to height in the dimensions of an image. Video and still picture frames have a frame aspect ratio.

For example, DV NTSC has a frame aspect ratio of 4:3 (or 4.0 width by 3.0 height). A typical widescreen frame has a frame aspect ratio of 16:9. Many cameras that have a widescreen mode can record using the 16:9 aspect ratio. Many films have been shot using even wider aspect ratios.

Frame aspect ratio
A 4:3 frame aspect ratio (left), and wider 16:9 frame aspect ratio (right)

In Premiere Pro, you can implement the letterboxing or the pan and scan technique by using Motion effect properties such as Position and Scale.

Letterboxing

When you import clips shot in one frame aspect ratio into a project that uses another frame aspect ratio, you decide how to reconcile the different values. This placement leaves black bands above and below the movie frame, called letterboxing.

For example, two common techniques are used for showing a 16:9 movie on a 4:3 standard television. You can fit the entire width of the 16:9 movie frame within the 4:3 television frame.

Pan and scan

Pan and scan is an alternative method to use a project with another frame aspect ratio. Only a part of the frame is retained, while the rest is lost.

For example, another technique to show a 16:9 movie on a 4:3 standard television is to fill the 4:3 frame vertically with the entire height of the 16:9 frame. Then, you pan the horizontal position of the 16:9 frame within the narrower 4:3 frame so that important action always remains inside the 4:3 frame. 

Letterboxing and pan and scan
Letterboxing and pan and scan

Pixel aspect ratio

Pixel aspect ratio describes the ratio of width to height of a single pixel in a frame. The pixels that make up a frame have a pixel aspect ratio (sometimes referred to as PAR). Pixel aspect ratios vary because different video systems make various assumptions about the number of pixels that are required to fill a frame.

For example, many computer video standards define a 4:3 aspect ratio frame as 640x480 pixels high, which results in square pixels. The computer video pixels have a pixel aspect ratio of 1:1 (square). Video standards such as DV NTSC define a 4:3 aspect ratio frame as 720x480 pixels, which result in narrower, rectangular pixels. The DV NTSC pixels have a pixel aspect ratio of 0.91 (nonsquare). DV pixels, which are always rectangular, are vertically oriented in systems producing NTSC video and horizontally oriented in systems producing PAL video. Premiere Pro displays clip pixel aspect ratio next to the clip image thumbnail in the Project panel.

Pixel and frame aspect ratios
Pixel and frame aspect ratios

A. 4:3 square-pixel image displayed on 4:3 square-pixel (computer) monitor B. 4:3 square-pixel image interpreted correctly for display on 4:3 non-square pixel (TV) monitor C. 4:3 square-pixel image interpreted incorrectly for display on 4:3 non-square pixel (TV) monitor 

Note:

The clean aperture is the portion of the image that is free from artifacts and distortions that appear at the edges of an image. The production aperture is the entire image.

Distorted images

If you display rectangular pixels on a square-pixel monitor without alteration, images appear distorted. For example, circles distort into ovals. However, when displayed on a broadcast monitor, the images appear correctly proportioned because broadcast monitors use rectangular pixels. Premiere Pro can display and output clips of various pixel aspect ratios without distortion. Premiere Pro attempts to automatically reconcile them with the pixel aspect ratio of your project.

You could occasionally encounter a distorted clip if Premiere Pro interprets pixel aspect ratio incorrectly. You can correct the distortion of an individual clip by manually specifying the source clip pixel aspect ratio in the Interpret Footage dialog box. 

You can correct similar misinterpretations of groups of same-size files by editing the file Interpretation Rules.txt.

Distorted image
Distorted image

Use assets with various aspect ratios

When as asset is imported, Premiere Pro attempts to preserve the frame aspect ratio, pixel aspect ratio, and frame dimensions so the asset does not appear cropped or distorted.

  • For assets that contain metadata, these calculations are automatic and precise. For example:
  • When you capture or import NTSC footage with the ATSC frame size of 704x480, the D1 frame size of 720x486, or the DV frame size of 720x480, the pixel aspect ratio is set to D1/DV NTSC (0.91).
  • When you capture or import footage with the HD frame size of 1440x1080, the pixel aspect ratio is set to HD 1080 Anamorphic (1.33).
  • When you capture or import PAL footage with the D1 or DV resolution of 720x576, the pixel aspect ratio is set to D1/DV PAL (1.094).

Assets that lack metadata, require a set of rules to interpret pixel aspect ratio. For other frame sizes, Premiere Pro assumes that the asset was designed with square pixels and changes the pixel aspect ratio and frame dimensions to preserve the image aspect ratio. If the imported asset is distorted, you can change the pixel aspect ratio manually.

Assets in a sequence

When you drag an asset into a sequence, the asset is placed at the center of the program frame by default. Depending on its frame size, the resulting image could be too small or over cropped for the needs of the project. Premiere Pro can change its scale automatically when you drag an asset into a sequence, or you can change it manually.

It is always important to interpreted files correctly. You can read asset frame dimensions and pixel aspect ratio near the preview thumbnail and in the Video Info column of the Project panel. You can also find this data in the asset Properties dialog box, the Interpret Footage dialog box, and the Info panel.

Aspect ratio distortion in sequences

The sequence settings preset you choose when you create a sequence sets the frame and pixel aspect ratios for the sequence. You can’t change aspect ratios after you create the sequence, but you can change the pixel aspect ratio that Premiere Pro assumes for individual assets.

For example, if a square-pixel asset generated by a graphic looks distorted in Premiere Pro, you can correct its pixel aspect ratio to make it look right. By ensuring that all files are interpreted correctly, you can combine footage with different ratios in the same project. Then you can generate output that doesn’t distort the resulting images.

Correct aspect ratio misinterpretations

Correct individual aspect ratio misinterpretations

To correct individual aspect ratio interpretation, do the following:

  1. Right-click the still image in the Project panel.

  2. Select Clip > Modify > Interpret Footage.

    Note:

    If you select a clip on the Timeline panel or Program monitor, the option is unavailable.

  3. Select one of the following in the Pixel Aspect Ratio section:

    Use Pixel Aspect Ratio From File

    Uses the original aspect ratio saved with the still image.

    Conform To

    Lets you choose from a list of standard aspect ratios.

    Modify clip
    Modify clip

    Note:

    When using Photoshop to generate images for use in video projects, it’s best to use the Photoshop preset named for the video format you’ll use. Using the preset ensures that your images are generated with the correct aspect ratio.

  4. Click OK.

Correct recurring aspect ratio misinterpretations

Premiere Pro automatically assigns pixel aspect ratios to files according to a file of rules. If a specific type of image is consistently misinterpreted (distorted) when you import it, you can change the relevant rule.

  1. Open a text editor.
  2. Within the text editor, go to the Premiere Pro Plug-ins folder.

  3. Open the file named Interpretation Rules.txt.
  4. Edit the rule you want to modify, and choose Save.

Common pixel aspect ratios

Pixel aspect ratio

When to use

Square pixels

1.0

Footage has a 640x480 or 648x486 frame size, is 1920x1080 HD (not HDV or DVCPRO HD), is 1280x720 HD or HDV, or was exported from an application that doesn’t support nonsquare pixels. This setting can also be appropriate for footage that was transferred from film or for customized projects.

D1/DV NTSC

0.91

Footage has a 720x486 or 720x480 frame size, and the desired result is a 4:3 frame aspect ratio. This setting can also be appropriate for footage that was exported from an application that works with nonsquare pixels, such as a 3D animation application.

D1/DV NTSC Widescreen

1.21

Footage has a 720x486 or 720x480 frame size, and the desired result is a 16:9 frame aspect ratio.

D1/DV PAL

1.09

Footage has a 720x576 frame size, and the desired result is a 4:3 frame aspect ratio.

D1/DV PAL Widescreen

1.46

Footage has a 720x576 frame size, and the desired result is a 16:9 frame aspect ratio.

Anamorphic 2:1

2.0

Footage was shot using an anamorphic film lens, or it was anamorphically transferred from a film frame with a 2:1 aspect ratio.

HDV 1080/DVCPRO HD 720, HD Anamorphic 1080

1.33

Footage has a 1440x1080 or 960x720 frame size, and the desired result is a 16:9 frame aspect ratio.

DVCPRO HD 1080

1.5

Footage has a 1280x1080 frame size, and the desired result is a 16:9 frame aspect ratio.

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