Copyright: « 1994, 1995 miro Computer Products AG


miroVIDEO DC1 tv help
miroVIDEO DC1 tv Video Format settings

The Setup menu item and the Video Format command open the Video Format window.

For more information on the settings, click the desired item using the mouse.

Image Dimensions

Cropping

Image Format

MJPEG Settings


 Image Dimensions

Sets the image size of a video sequence: Full size (presetting), 1/2, and 1/4. The 1/2 and 1/4 image sizes are suitable for special applications operating at a low data rate, such as for video clips which will only be played back on the computer.


Cropping

The cropping factor specifies how many lines will be cut off the screen margin. Video images have invisible irrelevant image margins. These margins can be cut off. In doing so, the amount of data to be compressed becomes smaller and the video sequence can be captured at a better quality. The cropping factors available range from «0» (full resolution) to «8». 8 pixels are cut off the left and the right margin and 6 pixels are cut off at the top and at the bottom. The remaining image section is always in the centre, the 4:3 ratio of height to width remains. The default value is «0». The optimal cropping factor for the full resolution lies between two and three.

To play back a PAL video sequence in the NTSC format, select the cropping factor «8».

When playing back a PAL video sequence in the NTSC format, the encoder expects an image every 0.03 seconds. A PAL video sequence, however, supplies an image every 0.04 seconds: the video sequence will not be played back smoothly. To avoid this, select the Synchronize Video Speed command from the Video menu in VidEdit.

VideoStudio does not offer the synchronisation as yet.


 Image Format

Sets the image format. If you select MJPEG Compressed, the video sequence is captured in the MJPEG format. It can only be played back using JPEG hardware, such as miroVIDEO DC1 tv.

The MJPEG Compressed option is suited for capturing video sequences, although this setting also allows to capture single-frames. The 16 Bit RGB and 24 Bit RGB options capture single-frames. Single-frames can only be output on computer monitors.

To play back a video sequence on a computer without JPEG hardware, open the video sequence in the Video Editor or in Adobe Premiere and choose a suitable compression method (e.g. «Cinepak») when saving the video sequence.


MJPEG Settings

When capturing video sequences large amounts of data have to be moved in a short time from miroVIDEO DC1 tv to the hard disk or the memory. To set the capture quality manually, switch on the Automatic Quality Control. The values range from 100% (maximum quality, high amount of image data, low compression) to 0% (low image quality, low amount of image data, maximum compression).

If the Automatic Quality Control is active, the data rate can be specified before capturing the video sequence. If video sequences are captured at a fixed data rate, the quality of individual images may differ (depending on the amount of information). The slider at the bottom of the window lets you set the JPEG Start Quality if the Automatic Quality Control is activated. The slider sets the maximum quality to be achieved.

The slider can only adjust itsself to a lower quality. Do not select a JPEG Start Quality which is too low.

The slider at the bottom of the window allows to set the JPEG quality manually: All images are compressed at the same JPEG quality. If the computer performance is not sufficient for the JPEG Quality, individual frames are dropped during capturing. The number and the percentage of those »dropped frames« are displayed afterwards. If frames have been dropped, select a lower start quality when capturing the video sequence again.

For more information, please read the »Tips & tricks for miroVIDEO DC1 tv« chapter in the manual.


Copyright  (c)1994, 1995  by

miro Computer Products AG,

Carl-Miele-Str.4,

D-38112 Braunschweig