Fix clipping of images that are partially left of the video
surface, they would get clipped on the right side instead of
the left side, because the video unpack functions currently
ignore the x offset parameter. Work around that until that
is implemented.
https://bugzilla.gnome.org/show_bug.cgi?id=739281
In case of overlay being completely or partially outside
the video frame, the offset calculations are not right,
which resulted in the overlay not being displayed as
expected, or crashes due to invalid memory access.
When the overlay rectangle is completely outside,
we need not render the overlay at all.
For partial display of overlay rectangles, src_yoff
was not being calculated, hence it was always clipping
the bottom half of the overlay, By calculating the
src_yoff, now the overlay is clipped properly.
https://bugzilla.gnome.org/show_bug.cgi?id=739281
There are some few but certain conditions where it is possible for the
dest_width to be smaller than x. So we check this before assigning a negative
value to src_width, which is a unsigned and would be promoted to a number that
can segfault videoblend.
https://bugzilla.gnome.org/show_bug.cgi?id=738242
We only allocate 8 bits per component for our temp buffers, which
causes invalid memory accesses if we try to unpack formats that
unpack into a format with 16 bits per component such as e.g. v210.
We don't support blending onto those yet, so just bail out.
The x/y values are meant to be signed.
This bug was introduced by 76c0881549
Conflicts:
gst-libs/gst/video/video-blend.c
gst-libs/gst/video/video-blend.h
gst_buffer_set_qdata() will leak the structure passed to it
when called incorrectly (e.g. on a non-metadata-writable buffer).
This is expected, but we must avoid doing that in valgrind.
Try to avoid floating point maths for each pixel to be blended in
inner loop, and try to avoid the multiplication entirely for the
most common case of the global alpha being 1. Could probably be
refactored a bit more.
