What is OSD (on screen display) module
The on-screen display unit (OSD) generates the output video signal.
It mixes together the information from up to five hardware windows, one of which is a cursor, two YCrCb video data, and the last two are user-defined bitmaps that can be used to display a menu on the screen for example.
The OSD windows priority is: (in the order of increasing priority.). - Video window 0 - Video window 1 - Bitmap window 0 - Bitmap window 1 - Cursor window. The priority order is fixed. If overlapping occurs between different windows, the color of each pixel corresponds to the color of the window with the highest priority. Although, transparency and blending factor can be setup for the bitmap windows.
The DSC24 main video window supports 2 ping-pong buffers. The address of the buffers is stored in separate registers so that they can be switched easily with a select signal. This feature is particularly useful in video decoding to decode the video data into one buffer and display the data coming from the other one.
If transparency is enabled, then any pixel on the bitmap windows with a value of 0 will allow the video window to be displayed (more or less depending of the blending factor). Pixels with a different color than the background color (0) will not let the video information go thru.
OSD window can be hided by following method so that video window behind it can be seen. The OSD window is on top of the video window. The attribute window controlling the transparency of the OSD window is the /dev/fb/2 device. Every pixel is represented by a nibble (4 bits) with values ranging from 7 (no transparency) to 0 (full transparency). Executing "cat /dev/zero > /dev/fb/2" on the target will write all zeros into the attribute window making the OSD window completely transparent and the video window visible.
Sorce: http://www-k.ext.ti.com/SRVS/CGI-BIN/WEBCGI.EXE/,/?St=118,E=0000000000013385295,K=7525,Sxi=0,Case=obj(19767)
http://www-k.ext.ti.com/srvs/cgi-bin/webcgi.exe?Company={5761bcd8-11f5-4e08-84e0-8167176a4ed9},new,kb=dsp
search query: osd
It mixes together the information from up to five hardware windows, one of which is a cursor, two YCrCb video data, and the last two are user-defined bitmaps that can be used to display a menu on the screen for example.
The OSD windows priority is: (in the order of increasing priority.). - Video window 0 - Video window 1 - Bitmap window 0 - Bitmap window 1 - Cursor window. The priority order is fixed. If overlapping occurs between different windows, the color of each pixel corresponds to the color of the window with the highest priority. Although, transparency and blending factor can be setup for the bitmap windows.
The DSC24 main video window supports 2 ping-pong buffers. The address of the buffers is stored in separate registers so that they can be switched easily with a select signal. This feature is particularly useful in video decoding to decode the video data into one buffer and display the data coming from the other one.
If transparency is enabled, then any pixel on the bitmap windows with a value of 0 will allow the video window to be displayed (more or less depending of the blending factor). Pixels with a different color than the background color (0) will not let the video information go thru.
OSD window can be hided by following method so that video window behind it can be seen. The OSD window is on top of the video window. The attribute window controlling the transparency of the OSD window is the /dev/fb/2 device. Every pixel is represented by a nibble (4 bits) with values ranging from 7 (no transparency) to 0 (full transparency). Executing "cat /dev/zero > /dev/fb/2" on the target will write all zeros into the attribute window making the OSD window completely transparent and the video window visible.
Sorce: http://www-k.ext.ti.com/SRVS/CGI-BIN/WEBCGI.EXE/,/?St=118,E=0000000000013385295,K=7525,Sxi=0,Case=obj(19767)
http://www-k.ext.ti.com/srvs/cgi-bin/webcgi.exe?Company={5761bcd8-11f5-4e08-84e0-8167176a4ed9},new,kb=dsp
search query: osd
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