diff options
| author | Sebastian Dröge <sebastian@centricular.com> | 2018-07-20 16:25:02 +0300 |
|---|---|---|
| committer | Sebastian Dröge <sebastian@centricular.com> | 2018-07-23 18:59:33 +0300 |
| commit | b0ae6a522186d5c123612eedc847b04eeeed6b65 (patch) | |
| tree | b83e496baaf37e7885209a2f5cd298e72e2a09a6 /gst | |
| parent | 14ab3972ef46ae6c36c975254875cb8bd65848c5 (diff) | |
compositor: Use 255 as maximum alpha instead of 256
255 will easily become 0 in the blending function as they expect
the maximum value to be 255.
Can be reproduce with
gst-launch-1.0 videotestsrc pattern=ball ! c.sink_0 \
videotestsrc pattern=snow ! c.sink_1 \
compositor name=c \
sink_0::zorder=0 sink_1::zorder=1 sink_0::crossfade-ratio=0.5 \
background=black ! \
videoconvert ! xvimagesink
crossfade-ratio +/- 0.001 makes it work correctly and the same happens
at e.g. 0.25, 0.75, N*0.0625
https://bugzilla.gnome.org/show_bug.cgi?id=796846
Diffstat (limited to 'gst')
| -rw-r--r-- | gst/compositor/blend.c | 12 |
1 files changed, 5 insertions, 7 deletions
diff --git a/gst/compositor/blend.c b/gst/compositor/blend.c index b36c16465..416f78cfb 100644 --- a/gst/compositor/blend.c +++ b/gst/compositor/blend.c @@ -33,8 +33,6 @@ #include <gst/video/video.h> -#define BLEND(D,S,alpha) (((D) * (256 - (alpha)) + (S) * (alpha)) >> 8) - GST_DEBUG_CATEGORY_STATIC (gst_compositor_blend_debug); #define GST_CAT_DEFAULT gst_compositor_blend_debug @@ -61,7 +59,7 @@ method##_ ##name (GstVideoFrame * srcframe, gint xpos, gint ypos, \ dest_width = GST_VIDEO_FRAME_COMP_WIDTH (destframe, 0); \ dest_height = GST_VIDEO_FRAME_COMP_HEIGHT (destframe, 0); \ \ - s_alpha = CLAMP ((gint) (src_alpha * 256), 0, 256); \ + s_alpha = CLAMP ((gint) (src_alpha * 255), 0, 255); \ \ /* If it's completely transparent... we just return */ \ if (G_UNLIKELY (s_alpha == 0)) \ @@ -247,7 +245,7 @@ _blend_##format_name (const guint8 * src, guint8 * dest, \ return; \ } \ \ - b_alpha = CLAMP ((gint) (src_alpha * 256), 0, 256); \ + b_alpha = CLAMP ((gint) (src_alpha * 255), 0, 255); \ \ BLENDLOOP(dest, dest_stride, src, src_stride, b_alpha, src_width, src_height);\ } \ @@ -492,7 +490,7 @@ _blend_##format_name (const guint8 * src, guint8 * dest, \ return; \ } \ \ - b_alpha = CLAMP ((gint) (src_alpha * 256), 0, 256); \ + b_alpha = CLAMP ((gint) (src_alpha * 255), 0, 255); \ \ BLENDLOOP(dest, dest_stride, src, src_stride, b_alpha, src_width, src_height); \ } \ @@ -691,7 +689,7 @@ blend_##name (GstVideoFrame * srcframe, gint xpos, gint ypos, \ src_stride = GST_VIDEO_FRAME_COMP_STRIDE (srcframe, 0); \ dest_stride = GST_VIDEO_FRAME_COMP_STRIDE (destframe, 0); \ \ - b_alpha = CLAMP ((gint) (src_alpha * 256), 0, 256); \ + b_alpha = CLAMP ((gint) (src_alpha * 255), 0, 255); \ \ /* adjust src pointers for negative sizes */ \ if (xpos < 0) { \ @@ -857,7 +855,7 @@ blend_##name (GstVideoFrame * srcframe, gint xpos, gint ypos, \ src_stride = GST_VIDEO_FRAME_COMP_STRIDE (srcframe, 0); \ dest_stride = GST_VIDEO_FRAME_COMP_STRIDE (destframe, 0); \ \ - b_alpha = CLAMP ((gint) (src_alpha * 256), 0, 256); \ + b_alpha = CLAMP ((gint) (src_alpha * 255), 0, 255); \ \ xpos = GST_ROUND_UP_2 (xpos); \ \ |