Section 49. Control Interlacing and Field Options

49. Control Interlacing and Field Options

BEFORE YOU BEGIN

29 About the Timeline and Video Tracks

40 Slow/Speed/Reverse Audio/Video

SEE ALSO

50 Freeze a Frame

124 About Troubleshooting DVD Output

Considering that most people use video from various sources (not just digital video), a number of issues might arise when you combine these various video sources in a movie project. One of these issues is related to interlaced and deinterlaced video. Basically, each frame of video has two fields that are woven or laced together with another frame to form a single frame of video. For more information on interlacing, deinterlacing, progressive scans, and fields, see 18 About Troubleshooting Media Additions.

49. Control Interlacing and Field Options

KEY TERMS

Interlaced Two video frames merged into one using each frame's odd or even fields. Interlaced video draws only half of the lines on the screen for each frame, taking advantage of the time it takes for a image to fade on a TV and giving the impression of double the actual refresh rate, helping to prevent flicker.

Deinterlaced The process of converting interlaced images into non-interlaced form by creating two frames out of one interlaced frame.

Under most circumstances, you will probably not have to be concerned about these two types of displays. There is, however, a growing need to be able to interlace or deinterlace video for use in your movie projects. Video that comes from televisioneither NTSC or PALis interlaced and will be fine if the final product will also be viewed on a television. However, the interlaced video will not look so good when viewed on your computer (such as if you post the interlaced video on your web page for viewing in a browser window). On the other hand, video designed for the Internet and computer display will not look so good when played on a television.

TIP

By connecting your camcorder or digital converter's out ports to a television set's in ports, you can view your video while it is still on the Timeline. Your television will give you the exact image as it will appear when viewed on a DVD. See the user's manual that came with your converter or camcorder for instructions on how to set up your television as a monitor.

To deal with these issues, Premiere Elements provides various field options you can manipulate for each clip individually.

1.	Right-click a Clip in the Timeline Right-click a clip in the Timeline to select it and open the clip's context menu.
2.	Select Field Options From the context menu, select Field Options to open the Field Options dialog box.
3.	Select Reverse Field Dominance The first option is Reverse Field Dominance. Enable this option to reverse the display order of the fields for the clip. If the capture was performed in another application or if the clip comes from an unknown source, Premiere Elements might not display the field order in the same way. Usually this will be noticed as jerky motion when the video is played. Reversing the field dominance resolves some problems with jerky video. You might also have to enable the Reverse Field Dominance option if you are going to play a clip in reverse, as explained in 40 Slow/Speed/Reverse Audio/Video.
4.	Select Processing Options and Click OK You can also set Processing Options for the selected clip (the default setting is None). The three additional options are Interlace Consecutive Frames, Always Deinterlace, and Flicker Removal: Choose None if you do not want to process the clip's fields. Choose Interlace Consecutive Frames to convert progressive scan frames to interlaced fields. Choose Always Deinterlace to convert interlaced fields into progressive scan frames. The fields are determined by the Fields Setting option, accessed from the Project, Project Settings, General menu command. Choose Flicker Removal to keep the image from flickering by blurring the two interlaced fields together. (In interlaced clips, some parts of images appear only in every other field, resulting in flickering. This is most prevalent with very thin horizontal details in still images.) NOTE For more details on flicker removal, see 25 Remove Shimmer from a Photo. After you have made the appropriate selections for your video clip, click the OK button. You might have to apply various combinations and test each one before getting the results for which you are looking.
5.	Select Frame Blend To further minimize interlacing problems, right-click the clip in the Timeline and choose Frame Blend from the clip context menu. This option is just a check on the menu itself, but it blends speed changes to improve the appearance of your clip. It blends frames together to provide a smoother-looking video if the speed of the clip is not set to 100%.