Marko Mäkelä kirjoitti: > On Mon, Sep 18, 2006 at 11:39:57AM +0200, Martin Wache wrote: > >>Can you please point out to me what the advantage of using the >>subpicture layer is? To me it looks like the main speed change is that >>you don't scale the osd. Or does the change to YV12 colourspace bring >>some speed advantage? > > > Some time ago, I tested replacing the YUY2 colour space conversion > with a memcpy(). The memcpy() was about twice as fast on my > 900 MHz Celeron, saving another 10% to 15% of CPU. On his 450 MHz P2, > this change is probably crucial.
I didn't receive the above Martin's message at all - off list, perhaps? Anyway, if it's still about the topic in question, the keyword for using the subpicture layer from my perspective is 'incompetence': I couldn't get crtc2 (mgatv) video layer working with YV12 colourspace and blitted OSD, so, I thought maybe it'd work with a subpicture layer more effortlessly, and it did. So, the advantage for me isn't the OSD really, but the YV12 for the crtc2 video. YV12->YUY2 was simply too slow. Using YV12 and LUT44 both bring advantages of reduced memory requirements and are generally faster. I didn't implement the scaling routines for the LUT44 OSD, because I simply didn't grasp the idea of the existing code in 5 seconds, and realized that scaling would practically never be required by the tv output. -- Heikki Lindholm _______________________________________________ Softdevice-devel mailing list [email protected] https://lists.berlios.de/mailman/listinfo/softdevice-devel
