FOCUS Enhancements MX-4DV Video Scaling Artifacts, Freeze Quality, Video Processing Artifacts

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MX-4 DV USER GUIDE APPENDIX APPENDIX C

VIDEO SCALING ARTIFACTS

Reducing a video image’s size can create artifacts because some picture information must be dis- carded to reduce the number of pixels in the image. In some cases, picture information might dis- appear when eliminating pixels. For example, lines in the image might appear jagged when the MX-4 DV removes pixels and, therefore, parts of the line.

Some MX-4 DV transitions scale an image down gradually. This might cause small features to appear and disappear as the image scales down.

The artifacts described here are normal when performing advanced effects. They are normally minor when running transitions at normal speeds.

FREEZE QUALITY

You can set the MX-4 DV to freeze either a frame or a field (refer to “Force Field Freeze” on page 72).

Freeze Field captures one field (half a video frame) and duplicates it to make the two fields that comprise a frame. This eliminates flashing caused when an object occupies a different position in the two captured fields, or when an object is so small it appear in only one field. The MX-4 DV’s Field Freeze eliminates flashing artifacts but reduces vertical resolution because it shows only one field.

Freeze Frame captures all fields in the image. This produces a higher quality image, but some flashing might occur.

VIDEO PROCESSING ARTIFACTS

Video processing circuits (such as enhancers, sharpness controls, and the playback circuitry in some VCR’s) can over-processthe video. This might cause the video signal to interfere with the invisible sync portion of the signal, thus making the signal non-standard. Video lines might shift to the right, black lines might enter the picture area from the left edge of the screen, white flashes might appear, the video image might be shredded, or you might see video tearing.

Normal Picture Picture with Video Tearing

When these types of artifacts occur, reduce or remove the processing to bring the signal back to normal. VCR’s and camcorders often have controls that can disable extra processing. If your VCR or camcorder has a Sharpness control, set it to zero or turn it off. If the device has an Edit switch, turn it on.