From 0fdc1ca818a4d03e187b2467cf23fa4196ccb94d Mon Sep 17 00:00:00 2001 From: Mathieu Duponchelle Date: Tue, 29 Dec 2020 20:24:51 +0100 Subject: compositor/blend: fix blending of subsampled components The correct way to determine the byte offset at a certain yoffset in a subsampled component is to shift the yoffset by the component's hsub This fixes out-of-bounds memory accesses and visible artefacts, example pipeline with the samples from #802: gst-launch-1.0 compositor name=vmixer sink_1::xpos=1910 sink_1::ypos=1080 ! \ videoconvert ! videorate ! xvimagesink \ filesrc location=VID_20200723_203606.mp4 ! decodebin name=demux1 ! \ queue ! videoflip method=vertical-flip ! vmixer. \ filesrc location=bridgeoverstubbledwater.mp4 ! decodebin name=demux2 ! \ queue ! vmixer. Part-of: --- gst/compositor/blend.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/gst/compositor/blend.c b/gst/compositor/blend.c index 41e20c033..531b47294 100644 --- a/gst/compositor/blend.c +++ b/gst/compositor/blend.c @@ -374,7 +374,7 @@ blend_##format_name (GstVideoFrame * srcframe, gint xpos, gint ypos, \ comp_xpos = (xpos == 0) ? 0 : GST_VIDEO_FORMAT_INFO_SCALE_WIDTH (info, 1, xpos); \ comp_ypos = (ypos == 0) ? 0 : GST_VIDEO_FORMAT_INFO_SCALE_HEIGHT (info, 1, ypos); \ comp_xoffset = (xoffset == 0) ? 0 : GST_VIDEO_FORMAT_INFO_SCALE_WIDTH (info, 1, xoffset); \ - comp_yoffset = (yoffset == 0) ? 0 : GST_VIDEO_FORMAT_INFO_SCALE_HEIGHT (info, 1, yoffset); \ + comp_yoffset = (yoffset == 0) ? 0 : yoffset >> info->h_sub[1]; \ _blend_##format_name (b_src + comp_xoffset + comp_yoffset * src_comp_rowstride, \ b_dest + comp_xpos + comp_ypos * dest_comp_rowstride, \ src_comp_rowstride, \ @@ -390,7 +390,7 @@ blend_##format_name (GstVideoFrame * srcframe, gint xpos, gint ypos, \ comp_xpos = (xpos == 0) ? 0 : GST_VIDEO_FORMAT_INFO_SCALE_WIDTH (info, 2, xpos); \ comp_ypos = (ypos == 0) ? 0 : GST_VIDEO_FORMAT_INFO_SCALE_HEIGHT (info, 2, ypos); \ comp_xoffset = (xoffset == 0) ? 0 : GST_VIDEO_FORMAT_INFO_SCALE_WIDTH (info, 2, xoffset); \ - comp_yoffset = (yoffset == 0) ? 0 : GST_VIDEO_FORMAT_INFO_SCALE_HEIGHT (info, 2, yoffset); \ + comp_yoffset = (yoffset == 0) ? 0 : yoffset >> info->h_sub[2]; \ _blend_##format_name (b_src + comp_xoffset + comp_yoffset * src_comp_rowstride, \ b_dest + comp_xpos + comp_ypos * dest_comp_rowstride, \ src_comp_rowstride, \ -- cgit v1.2.1