Transition: matte

Plugin Information

title: Matte
media types: Video
description: Replace the alpha channel of track A with the luma channel from track B.
version: 1
creator: Maksym Veremeyenko
copyright: Meltytech, LLC
license: LGPLv2.1

Notes

Please note that the transition automatically detects if the frame from track B has scaled or non-scaled luma. The frame property "full_luma" should indicate it. If you need to prepare fill and key (matte) files, you can use melt or ffmpeg to extract alpha channel from existing video: melt sg_gm_2013_clip_title.avi -attach frei0r.alpha0ps 0=0.21 -consumer \ avformat:sg_gm_2013_clip_title.matte_scaled.mp4 crf=10 preset=placebo an=1 ffmpeg -i sg_gm_2013_clip_title.avi -vf "alphaextract" -pix_fmt \ yuv422p -preset placebo -crf 10 -y sg_gm_2013_clip_title.matte_scaled.mp4 Because the example above provides a scaled luma output, the transition performs scaling from [16,235] -> [0, 255]. It is possible to create unscaled (full) range: melt sg_gm_2013_clip_title.avi -attach frei0r.alpha0ps 0=0.21 -consumer \ avformat:sg_gm_2013_clip_title.matte_full.mp4 crf=10 preset=placebo an=1 \ mlt_image_format=rgb24a pix_fmt=yuvj422p ffmpeg -i sg_gm_2013_clip_title.avi -vf "alphaextract" -pix_fmt \ yuvj422p -preset placebo -crf 10 -y sg_gm_2013_clip_title.matte_full.mp4 The fill can be converted from rgba to yuv422: melt sg_gm_2013_clip_title.avi -consumer avformat:sg_gm_2013_clip_title.fill.mp4 \ crf=10 preset=placebo an=1 ffmpeg -i sg_gm_2013_clip_title.avi -pix_fmt yuv422p -preset placebo -crf 10 -y \ sg_gm_2013_clip_title.fill.mp4 Putting it all together: melt sg_gm_2013_clip_title.matte_full.mp4 -track noise: -track \ sg_gm_2013_clip_title.fill.mp4 -transition matte a_track=2 \ b_track=0 -transition composite a_track=1 b_track=2

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