Otherwise vdp_video_mixer_destroy() would later fail when called on an invalid
video mixer handle. With mesa r600 vdpau driver, this would cause a segfault.
Until now, failure to allocate image data resulted in a crash (i.e.
abort() was called). This was intentional, because it's pretty silly to
degrade playback, and in almost all situations, the OOM will probably
kill you anyway. (And then there's the standard Linux overcommit
behavior, which also will kill you at some point.)
But I changed my opinion, so here we go. This change does not affect
_all_ memory allocations, just image data. Now in most failure cases,
the output will just be skipped. For video filters, this coincidentally
means that failure is treated as EOF (because the playback core assumes
EOF if nothing comes out of the video filter chain). In other
situations, output might be in some way degraded, like skipping frames,
not scaling OSD, and such.
Functions whose return values changed semantics:
mp_image_alloc
mp_image_new_copy
mp_image_new_ref
mp_image_make_writeable
mp_image_setrefp
mp_image_to_av_frame_and_unref
mp_image_from_av_frame
mp_image_new_external_ref
mp_image_new_custom_ref
mp_image_pool_make_writeable
mp_image_pool_get
mp_image_pool_new_copy
mp_vdpau_mixed_frame_create
vf_alloc_out_image
vf_make_out_image_writeable
glGetWindowScreenshot
This factors out some code from vo_vdpau.c, especially deinterlacing
handling. The intention is to use this for vo_vdpau.c to make the logic
significantly easier, and to use it for vo_opengl (gl_hwdec_vdpau.c) to
allow selecting deinterlace and postprocessing modes.
As of this commit, the filter actually does nothing, since both vo_vdpau
and vo_opengl treat the generated images as normal vdpau images. This
will change in the following commits.