Thanks for your response Brian! You say you are able to use OSD0 in 1024x768x16bpp.
1) Can you also use OSD1 at the same time as an attribute windows to let VID0 show through? E.g. have a D1 30fps video playing over a 1024x768 graphic background? 2) When you say "...If you need to do some form of animation on the OSD window, you'll have to do some work to understand the limitations, especially if you are using OSD1 as an attribute window for per-pixel alpha blending... ", what kind of limitation are we talking about? I know about the rendering speed limitation of the 297MHz ARM, but other than that? 3) I guess I don't understand the equation in section 4.3.1 of sprue37c.pdf (Video Window Constraints). According to the equation, using OSD0 in 1024x768 at 30 fps seems to exceed the specified limit of 25 Mbytes/second. [(1024 * 768) * 2bpp + (720 * 480) * 0.5bpp] * 30 = [1572864 + 172800] * 30 = ~52 Mbytes/sec What am I missing? Thanks again! On Tue, Oct 14, 2008 at 4:57 PM, Brian Rhodes <[EMAIL PROTECTED]> wrote: > > > Carl Renaud wrote: >> >> Hi, >> I am seeking advice on the DM6446... >> Our product requirements >> ================== >> Display a 1024x768 graphic background with a video overlay. Using the >> DM6446, there is no problem doing this is in D1 resolution, using VID0 for >> video, OSD0 for graphics and OSD1 for transparency. For resolutions higher >> than D1, there seems to be a few limitations... >> Methods >> ====== >> 1) The first method would be to use VID0 for video, OSD0 for >> graphics(RGB565) and OSD1 for transparency. >> I read in the VPBE document (section 4.3.1 of sprue37) that the combined >> bandwith of the OSDs cannot be more than 25MB/sec. This is exactly a D1 >> resolution OSD at 30 fps. So... this method would not work... Correct? >> > > I am not having trouble drawing 1024x768x16bpp graphics to OSD0. To prevent > tearing, use the memory you would have for Video 1 window and implement > panning in the framebuffer driver. Your 'product requirement' has a full > screen graphic background, and for that OSD0 will suffice. If you need to do > some form of animation on the OSD window, you'll have to do some work to > understand the limitations, especially if you are using OSD1 as an attribute > window for per-pixel alpha blending. >> >> 2) The second method would be to use VID0 for graphics(RGB888) and VID1 for >> video (as a picture in picture). >> In the VPBE document (again section 4.3.1 of sprue37), it is stated that >> when doing HD, VID0 should be used and VID1 disabled. Also, reading through >> the mailing list, it seems that there is a silicon problem on the DM6446 >> that prevents using VID0 and VID1 at the same time. So... this method >> would not work... Correct? > > You are correct. You cannot use Video 1 when the resolution of Video 0 is > > 720x576. The bug in the silicon causes a flicker when both Video 1 and Video > 0 are used at lower resolutions. > >> 3) The third method would be to use VID0 for graphics(RGB888), OSD0 for >> video(RGB565) and OSD1 for transparency. >> My understanding is that this should be possible if we limit the video to >> be a D1 frame within the 1024x768 graphics of VID0. This would respect the >> OSD bandwidth limitation. However, since OSD0 only takes RGB565 (and >> bitmap), I would need to convert the YUV 4:2:2 video to RGB565 on the ARM(or >> DSP). Correct? >> > > This would not be possible. You would not be able to do this colorspace > conversion quick enough. Codec implementations which do conversions between > 4:2:2 and 4:2:0 are simply reassembling the stream of data, throwing some > away in one direction, and duplicating some in the other. the conversion > from yuv -> rgb is considerably more work. >> >> Is my understanding correct? Is there any other option on the DM6446 to >> meet our requirements? >> Thank you! >> ------------------------------------------------------------------------ >> >> _______________________________________________ >> Davinci-linux-open-source mailing list >> [email protected] >> http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source >> _______________________________________________ Davinci-linux-open-source mailing list [email protected] http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
