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Video Scaler v4.0 User Guide
UG805 March 1, 2011
Chapter 7:
Scaler Aperture
Pixel 0 is defined as the first active pixel after the rising edge of
active_video_in
. This
is indicated in
Figure 7-2
. The value 128 is used as the default value in
video_data_in
during blanking. In this example, the first pixel in the horizontal scaler aperture is the first
active pixel in the input line.
Cropping
When using “Live” mode, you may choose to select a small portion of the input image. To
achieve this, set the
aperture_start_line
,
aperture_end_line
,
aperture_start_pixel
and
aperture_end_pixel
according to your requirements.
For example, from an input which is 720P, you may want to scale from a rectangle of size
80x60, starting at (pixel, line) = (20, 32). Set the following:
Figure 7-3
shows the opening of an internal processing window signal
(
t_verticalwindow
) with the preceding cropping settings. A similar operation occurs in
the horizontal domain. A useful developer note is that if the largest input rectangle is
cropped from the input, then this size may be used in deciding the
max_pixels_in_per_line
parameter. This may save block RAM usage in some cases.
When using “Memory” mode, cropping must be achieved by selecting the appropriate
rectangular area from memory.
aperture_start_pixel
and
aperture_start_line
must be set to zero.
X-Ref Target - Figure 7-2
Figure 7-2:
Active_video_in in Relation to First Active Sample
aperture_start_pixel
20
aperture_end_pixel
99
aperture_start_line
32
aperture_end_line
91
X-Ref Target - Figure 7-3
Figure 7-3:
Cropping from the Input Image
Содержание LogiCORE IP
Страница 1: ...LogiCORE IP Video Scaler v4 0 User Guide UG805 March 1 2011...
Страница 6: ...Video Scaler v4 0 User Guide www xilinx com UG805 March 1 2011...
Страница 14: ...14 www xilinx com Video Scaler v4 0 User Guide UG805 March 1 2011 Preface About This Guide...
Страница 18: ...18 www xilinx com Video Scaler v4 0 User Guide UG805 March 1 2011 Chapter 1 Introduction...
Страница 20: ...20 www xilinx com Video Scaler v4 0 User Guide UG805 March 1 2011 Chapter 2 Overview...
Страница 70: ...70 www xilinx com Video Scaler v4 0 User Guide UG805 March 1 2011 Chapter 9 Performance...
Страница 74: ...74 www xilinx com Video Scaler v4 0 User Guide UG805 March 1 2011 Appendix A Use Cases...
Страница 92: ...92 www xilinx com Video Scaler v4 0 User Guide UG805 March 1 2011 Appendix B Programmer Guide...