From 260596a5dd68e6c4b6b265b3afc0fea75b48030f Mon Sep 17 00:00:00 2001 From: Miguel Freitas Date: Mon, 8 Dec 2003 14:15:50 +0000 Subject: some notes about overlays CVS patchset: 5873 CVS date: 2003/12/08 14:15:50 --- doc/faq/faq.sgml | 109 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 109 insertions(+) diff --git a/doc/faq/faq.sgml b/doc/faq/faq.sgml index 47793583a..d5df5bbc9 100644 --- a/doc/faq/faq.sgml +++ b/doc/faq/faq.sgml @@ -1688,6 +1688,115 @@ + + OSD and overlay related questions + + + What is this "unscaled" OSD about? + + Since version 1-rc3 of xine-lib supports a new method for rendering OSD + (On Screen Display) and subtitles. This method uses a X11 extension + called XShape that allows using screen resolution instead of + stream resolution. It is called "unscaled" OSD because it does not + scales with the video being played. + + + Suppose you are watching a 320x200 video in full screen. Normal OSD + would be blended at 320x200 and then scaled to full screen (lets say, + 1024x768), resulting in big and ugly fonts. The unscaled overlay is + drawn directly to screen, creating a sharper and better looking OSD. + + + There are side effects too. Sometimes the unscaled overlay show some + glitch just before disappearing. Some people may be annoyed enough + by that and might want to disable the usage of unscaled overlay + altogether. + + + Unscaled OSD usage by subtitles and xine-ui is controlled by + the following settings + (~/.xine/config or ~/.gxine/config): +    gui.osd_use_unscaled:0 +    misc.spu_use_unscaled_osd:0 + + + + + I can't see the OSD or it leaves a black box over the image! + + If you are using xine-lib version 1-rc3 or newer, this is probably + due buggy XV drivers that do not support + unscaled OSD (the XShape + extension) properly. + + + There have being reports of some ATI drivers that don't allow + displaying anything over the video. The VIA Epia binary drivers + is reported to leave a black box where the OSD was displayed. + + + The problem may be fixed by either updating the video driver, + or disabling xine unscaled OSD support. + + + + + Why colors of overlays/subtitles seem to be "leaking"? + + xine blends most overlays, specially the ones from DVD discs, + directly over the image (scaled OSD). Unfortunately most codecs + (like MPEG2) use a subsampled image format (YV12) that makes + properly blending an interesting challenge. + + + In short, this is a known xine bug. There have being discussions + on improving the blending quality but, so far, nobody implemented + a better (scaled) overlay renderer. Contact developers if you want + to try doing something about it. + + + + + Why external subtitles look so ugly? + + You are probably using a xine-lib version older than 1-rc3. + Try upgrading your copy and read the + section about unscaled osd. + + + + + Why subtitles can't be displayed outside the video? + + It is possible, but older xine versions may not support it. There are two + alternatives for rendering the subtitles outside the video image: + + + + + + Use the "expand" post plugin to increase frame height adding + black bars to it. This will allow blending the subtitles + over the black bars, since they will be part of the video now. + + + + + Use unscaled OSD, as it + does not requires any video to render the subtitles on. + + + + + + Also notice that DVD overlays (including subtitles) are meant to + be displayed in a fixed position, this is how the DVD menu + highlighting works. xine does not support moving them. + + + + + Error Messages: What they mean and what you can do -- cgit v1.2.3