Downconverting HD Video

There are several methods for downconverting HD video to SD video:

Letterboxing 16:9 Video in a 4:3 Frame

To preserve the aspect ratio of widescreen movies on a 4:3 screen, widescreen movies are scaled until the width fits within the 4:3 frame. The remaining space at the top and bottom of the 4:3 frame is left empty and is usually black.

If a film or video was shot to be exclusively viewed in a widescreen venue, this technique is usually the best approach for downconversion. However, this method makes poor use of the already lower resolution of an SD 4:3 frame, because many lines are not used at all.

Figure. Canvas showing a widescreen image of a polar bear, and a diagram showing the scaling and letterboxing of 1080 x 4880 and 70 x 480 frames to a 4:3 aspect ratio.
To letterbox a 16:9 clip within a 4:3 sequence
  1. Create a sequence with a 4:3 aspect ratio. For example, choose the DV-NTSC or DV-PAL Easy Setup and then create a new sequence.

  2. Drag a clip with a 16:9 aspect ratio to the sequence.

    If a dialog appears asking if you want to conform your sequence settings to your clip, click No.

    The 16:9 sequence clip is now scaled to fit in the 4:3 sequence and appears letterboxed.

For more information, see Scaling Images and Video Clips to Match a Sequence.

Cropping 16:9 Video to 4:3

If you keep both 16:9 and 4:3 aspect ratios in mind during the shoot, making sure important action stays within the 4:3 center of the 16:9 frame, you can choose to crop your entire clip within a 4:3 frame. This method allows you to fill the whole 4:3 screen with some portion (usually the center) of your 16:9 image.

Figure. Diagram showing the crop center needed for cropping a 16:9 aspect ration clip to 4:3 aspect ratio frame size.

Note: For broadcast in the UK, 16:9 images are often cropped to 14:9 and letterboxed within a 4:3 frame (for PAL televisions). Because a 14:9 image has a less severe letterbox (that is, smaller black bars at the top and the bottom of the frame), some viewers find this less objectionable.

To crop and center a 16:9 clip within a 4:3 sequence
  1. Follow the instructions for scaling a 16:9 clip within a 4:3 sequence in Letterboxing 16:9 Video in a 4:3 Frame.

    The 16:9 sequence clip is now scaled to fit in the 4:3 sequence and appears letterboxed. Now you need to scale the clip up so that the sides are cropped.

  2. Double-click the sequence clip so that it opens in the Viewer, then click the Motion tab.

  3. If the Basic Motion parameters are not shown, click the Basic Motion disclosure triangle.

  4. While watching in the Canvas, drag the Scale slider to the right until the clip height matches the height of the Canvas.

    You can also enter the following value in the Scale field: the original value that appeared in the Scale field multiplied by 1.33. For example, if Final Cut Pro letterboxed your clip using a Scale value of 50, enter “66.5” (50 x 1.33) to scale the entire clip to the Canvas height.

    The sides of the clip are now cropped by the 4:3 sequence.

Pan and Scan

The pan and scan method crops 16:9 clips within a 4:3 frame, but each clip can be uniquely cropped to focus on a particular portion of the frame. The pan and scan method does not necessarily refer to panning during the transfer, but rather the fact that each frame may be cropped differently.

Figure. Diagram showing the pan and scan method of cropping for 16:9 clips within a 4:3 frame.
To crop and move a 16:9 clip within a 4:3 sequence
  1. Follow the instructions for scaling a 16:9 clip within a 4:3 sequence in Cropping 16:9 Video to 4:3.

    The sides of the clip are now cropped by the 4:3 sequence. Now you can move the clip horizontally to focus on different parts of the frame. If you scaled the clip beyond the height of the Canvas, you can also move the clip vertically.

  2. In the Canvas, choose Image+Wireframe from the View pop-up menu.

    Wireframe guides appear over the sequence clip.

  3. Choose Fit to All from the Zoom pop-up menu so you can see the boundaries of the clip.

  4. Make sure the Selection tool is active by clicking it in the Tool palette (or pressing A).

  5. While holding down the Shift key, drag the clip in the Canvas to the left or right to select a new framing for the clip.

    Holding down the Shift key restricts movement to a single axis so you can limit your adjustments to the horizontal axis.

Creating Artificial Pans in 16:9 Footage

In some complex scenes with multiple characters or centers of visual activity, an artificial camera move (a pan) can be introduced to recenter the widescreen action within the 4:3 frame.

In Final Cut Pro, you can crop and even perform simple pans by animating the Center parameter in the Motion tab. However, unless the animation is convincing, this can be more of a distraction than anything else. For more information on using the Motion tab and animating parameters, see Changing Motion Parameters and Animating Motion Effects Using Keyframes.

16:9 Anamorphic

You can use this method to preserve the 16:9 aspect ratio of HD video when scaling down to SD video. 16:9 anamorphic video squeezes a 16:9 image within a 4:3 aspect ratio, and the image is stretched during playback so it appears normal. Some DVD players and video monitors have an option to unsqueeze anamorphic video.

Figure. Diagram showing how a 16:9 anamorphic video squeezes a 16:9 image into a 4:3 aspect ratio, and the Viewer and Canvas windows showing a clip that has had that scaling applied.
To squeeze a 16:9 clip within a 16:9 anamorphic sequence
  1. Create a sequence with a 16:9 anamorphic aspect ratio. For example, choose the DV-NTSC Anamorphic or DV-PAL Anamorphic Easy Setup and then create a new sequence.

  2. Drag a clip with a 16:9 aspect ratio to the sequence.

    If a dialog appears asking if you want to conform your sequence settings to your clip, click No.

    The 16:9 sequence clip is now scaled to fit in the anamorphic 16:9 sequence, and the aspect ratio of the 16:9 clip is preserved even though you are working in an SD sequence.

For more information about anamorphic video, see Working with Anamorphic 16:9 Media.