Slices allowed filtering or drawing video in horizontal bands or
blocks. This allowed working on the video in smaller units. In theory,
this could bring a performance win by lowering cache pressure, as you
didn't have to keep the whole video frame in cache while filtering,
only the slice.
In practice, the slice code path was barely used for the following
reasons:
- Multithreaded decoding with ffmpeg didn't use slices. The ffmpeg
slice callback was disabled, because it can be called from another
thread, and the mplayer video chain is not thread-safe.
- There was nothing that would turn "full" images into appropriate
slices, so slices were rarely used.
- Most filters didn't actually support slices.
On the other hand, supporting slices lead to code duplication and more
complex code in general. I made some experiments and didn't find any
actual measurable performance improvements when using slices. Even
ffmpeg removed slices based filtering from libavfilter in favor of
simpler code.
The most broken thing about the slices code path is that slices can't
be queued, like it is done for images in vo.c.
By "design", mplayer normally allocates aligned images only inside the
filter chain, via the vf_get_image() function. This function pads the
width of the requested image if a stride is allowed, sets that new width
before calling mp_image_alloc_planes().
However, newer code wants aligned images as well (basically to satisfy
libswscale). This affects all uses of alloc_mpi(). To get aligned
strides, simply change alloc_mpi() to request an aligned width.
Remove the old hack in mp_image_alloc_planes(), which special cases some
image formats to be allocated with aligned strides.
This is a temporary hack until mp_image_alloc_planes() is revised.
Finish renaming directories and moving files. Adjust all include
statements to make the previous commit compile.
The two commits are separate, because git is bad at tracking renames
and content changes at the same time.
Also take this as an opportunity to remove the separation between
"common" and "mplayer" sources in the Makefile. ("common" used to be
shared between mplayer and mencoder.)
Tis drops the silly lib prefixes, and attempts to organize the tree in
a more logical way. Make the top-level directory less cluttered as
well.
Renames the following directories:
libaf -> audio/filter
libao2 -> audio/out
libvo -> video/out
libmpdemux -> demux
Split libmpcodecs:
vf* -> video/filter
vd*, dec_video.* -> video/decode
mp_image*, img_format*, ... -> video/
ad*, dec_audio.* -> audio/decode
libaf/format.* is moved to audio/ - this is similar to how mp_image.*
is located in video/.
Move most top-level .c/.h files to core. (talloc.c/.h is left on top-
level, because it's external.) Park some of the more annoying files
in compat/. Some of these are relicts from the time mplayer used
ffmpeg internals.
sub/ is not split, because it's too much of a mess (subtitle code is
mixed with OSD display and rendering).
Maybe the organization of core is not ideal: it mixes playback core
(like mplayer.c) and utility helpers (like bstr.c/h). Should the need
arise, the playback core will be moved somewhere else, while core
contains all helper and common code.
wm4