Commit e2150b11 authored by Committed by Sebastian DrögeBrowse files
textoverlay: converted AYUV to use 'A OVER B' alpha compositing
'A OVER B' compositing is explained at http://en.wikipedia.org/wiki/Alpha_compositing. Previously, overlaying text on a transparent background image left the text overlay also transparent. This pipeline shows such an example: gst-launch videotestsrc pattern=white ! video/x-raw-yuv,format=\(fourcc\)AYUV ! alpha alpha=0.0 ! textoverlay text=Testing auto-resize=False font-desc=60px ! videomixer ! ffmpegcolorspace ! autovideosink With this patch, text is composited "OVER" the background image and thus is visible regardless of the alpha of the background image. The overlay in the above pipeline works after applying this patch.
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