>>> Yes, there are significant quality issues. The composite bounding
>>> geometry being used here is set for 100% = the size of the profile. >>> So, I doubt that it is scaling. However, if you use a non-square pixel >>> profile, then the title's is going to be scaled horizontally to >>> conform its square pixels to the profile's sample aspect ratio. If > you >>> combine that with the sdl consumer's default scaler setting of > nearest >>> neighbor, you will get poor quality. However, in my brief tests I >>> specifically avoided these pitfalls. I even found the problem when >>> using the Qt-based kdenlive titler. Certainly, the combination of the >>> colors chosen and SD resolution limit the quality, but I noticed that >>> the affine transition's compositor does give better results. The >>> regular composite transition uses yuv422 with its reduced chroma >>> resolution, and that at least partially contributes to the problem. >>> Perhaps when you combine that with composite's lack of > interpolation >>> and these colors and low resolution. >> >> I produced these two images during my analysis. They were created in >> kdenlive using the kdenlive titler (not dynamictext's pango). They >> were made using a 768x576 square pixel profile. The right side of the >> image within the gray box does NOT use any of mlt's compositors; it >> uses Qt's. It is simply text over a rectangle were the rectangle is >> filled with the same color as the background color clip. The left side >> demonstrates the MLT transition used - affine vs. composite. If you >> flip back and forth between the two within an image viewer, it shows: >> >> a) The affine composite quality is roughly the same as Qt's (look at >> 'S' and 's'). >> b) The composite transition appears to have an off-by-one error >> between the image and the alpha channel. I do not yet know if it is >> really off or if it is just side-effect of the simple implementation. >> c) There is a lot of aliasing even within the Qt composited area as a >> result of low resolution. > > The previous two images were generated by rendering to H.264 and then > converting the first frame to PNG. Here are two new ones that render > straight from the project to PNG. Based on those results, is there any reason the watermark filter shouldn't use the affine transition by defaut? ~BM ------------------------------------------------------------------------------ LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free Trial Remotely access PCs and mobile devices and provide instant support Improve your efficiency, and focus on delivering more value-add services Discover what IT Professionals Know. Rescue delivers http://p.sf.net/sfu/logmein_12329d2d _______________________________________________ Mlt-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/mlt-devel
