stream: fix dvd:// + cache crashing

The language string was dynamically allocated, which completely fails
if the cache is forked (which it usually is). Change it back to a fixed
length string, like the original code had it.
mplayer: fix potential issue when ao_play() fails

ao_play() can fail; in that case a negative error code is returned.
This error code is returned by write_to_ao() in turn. The function
fill_audio_out_buffers(), which calls write_to_ao(), doesn't check for
any error codes, and will likely trigger the assertion following the
function call. Change write_to_ao() to return 0 on failure to hopefully
prevent crashes when AOs fail.
core: fix crash when video filter returns inf as PTS

When a video filter returned inf as PTS, the player crashed. One
reason for this was that decode_audio() was called with a negative
minlen parameter, which at some point caused it to call a memory
allocation function with a ridiculous value, triggering an out of
memory code path in talloc.c. (talloc.c has been modified to abort()
on out of memory situations.)

Fix this by sanity checking minlen in decode_audio(). (The check
against outbuf->len always succeeded, because it's an unsigned
comparison.)

Make an existing sanity check in mplayer.c more robust: check for NaN
too, which happens if the video PTS is inf.

This happened with "-vf pullup,softpulldown" (but is not triggered when
the following commit is applied).
vf_softpulldown: fix possible regression

The lines added with this commit were accidentally removed in commit
a0d759, which was a pure cleanup commit merged from mplayer-svn. The
difference between mplayer-svn and the mplayer2 base is that this
filter has been made PTS aware in mplayer2.

Also remove the redundant initialization of vf->priv->state.
m_option: add color option type

This accepts HTML-style hex colors in the form #RRGGBB. It's also
possible to provide an alpha component with #AARRGGBB. Each 2-digit
group is a hex number, which gives the color value from 0-255 (e.g.

There is existing code in subassconvert.c, which parses HTML-style
color values in SRT subs. This is not used: it's probably better if
option parsing is completely separate from code specific to certain
subtitle formats, even if a little code is duplicated.
osd: make the OSD and sub font more customizable

Make more aspects of the OSD font customizable. This also affects the
font used for unstyled subtitles (such as SRT), or when using the
--no-ass option. This adds back some customizability that was lost with
commit 74e7a1 (osd: use libass for OSD rendering).

Removed options:
--ass-border-color
--ass-color
--font
--subfont
--subfont-text-scale

Added options:
--osd-color
--osd-border
--osd-back-color
--osd-shadow-color
--osd-font
--osd-font-size
--osd-border-size
--osd-margin-x
--osd-margin-y
--osd-shadow-offset
--osd-spacing
--sub-scale

The font size is now specified in pixels as it would be rendered on a
window with a height of 720 pixels. OSD and subtitles are always scaled
with the window height, so specifying or expecting an absolute font
size doesn't make sense.

Such scaled pixel units are used to specify font border etc. as well.

(Note: the font size is directly passed to libass. How the fonts are
actually rasterized is outside of our control, but in theory ASS font
sizes map to "script" pixels and then are scaled to screen size.)

The default settings should be about the same, with slight difference
due to rounding to the new scales.

The OSD and subtitle fonts are not separately configurable. It has
limited use and would double the number of newly added options, which
would be more confusing than helpful. It could be easily added later,
should the need arise.

Other small details that change:
- ASS_Style.Encoding is not set to -1 for subs anymore
  (assuming subs use VSFilter direction in -no-ass mode too)
- use a different WrapStyle for OSD
- ASS forced styles are not applied to OSD
m_option: print valid integer range for choices on parsing errors

Only some choices have an additional integer range. For those which
do, printing the choices only would be confusing.

E.g. --cursor-autohide accepts the choices "always", "no", or an
integer value. The help text printed on option parse errors should
print the accepted integer range additional to "always" and "no".
manpage: minor fixes

The typo in options.rst was introduced in a54088.

--hardframedrop mentioned in mpv.rst has been merged with --framedrop.
mplayer: disable auto-loading of external codecs.conf

Do not load codecs.conf files located in $PREFIX/etc/mpv/ or ~/.mpv/.
There really is no use for this, other than possibly breaking things.
It's still possible to use --codecs-file explicitly to load an external
config file, and this option can be used in ~/.mpv/config.

While we're at it, remove the global codecs_file variable, and another
unused variable.
configure: add --disable-optimization, change --enable-debug semantics

--disable-optimization removes -O2 from CFLAGS.

Now --enable-debug only adds -g to CFLAGS, and doesn't disable
optimization anymore.

As an obscure feature, --enable-optimization=<n> adds -O<n> to CFLAGS.

Also remove stray $def_debug from configure.
configure: make --enable-debug default

This may result in larger binaries by default, and should be harmless
otherwise. Users are advised to use "make install-strip" if they want
binaries without debug symbols.
command: use yes/no instead of enabled/disabled for consistency

The idea is that the OSD uses the same names as the options, if
possible.
osd: fix OSD status symbol display in some cases

The playback status symbol in the OSD status display on video (such as
displayed when seeking or with the show_progress input command)
sometimes kept displaying the last seek, without resetting the symbol.
(For example: disable the OSD, seek, enable the OSD, run show_progress;
but also other cases.)

The main reason for that was the code clearing the OSD bar is also
responsible for clearing the osd_function (which stores the playback
symbol). If no OSD bar was set, the osd_function was never reset.

Fix by always setting the timer for clearing the OSD bar and the
osd_function whenever the osd_function is set. Clearing the OSD bar
when it wasn't set is OK. If the OSD bar is set some time after
osd_function is set, the timer is overwritten - that's a good thing,
as it makes both disappear from the screen at exactly the same time.

Always reset osd_function to 0 and determine the playback status
explicitly from mpctx->paused when displaying the status on screen.
core: minor cleanups

Enable printf format warnings for set_osd_[t]msg.
Remove the pointless assertion in mplayer.c (the assertion proved that
the following NULL check is probably pointless, but leave that check
anyway for robustness - it's not really clear whether it's needed).
gl_common: improve Mesa compatibility for GL3 context creation

Don't request CONTEXT_FORWARD_COMPATIBLE when creating a GL3 context on
X11. This improves compatibility with some Mesa drivers.

Setting this bit was originally intended to make the code compatible
to newer (future, possibly not yet existing) OpenGL implementations.
These implementations wouldn't have to support deprecated legacy GL
features, which we know that we don't use, and could return a context
with a higher OpenGL version than requested.

In practice, this didn't work out. CONTEXT_FORWARD_COMPATIBLE requires
the driver to explicitly disable deprecated functionality. If it doesn't
do that, it has to reject context creation with that flag set. And it
turns out there are Mesa drivers which suffer from this caveat. See [1].

This probably also means that a GL application with a fixed set of
required GL features (such as a subset of GL 3.2 core, like vo_opengl.c)
may need to probe several GL versions if drivers really start dropping
legacy GL.

On Windows, CONTEXT_FORWARD_COMPATIBLE is still set. It is not known
if this is ideal, but fortunately there is no Mesa on Windows.

CONTEXT_CORE_PROFILE is still always set. For requested GL versions
lower than 3.2, this flag is ignored. Should we requires higher versions
later, we want it to be set, so don't remove it.

[1] https://bugs.freedesktop.org/show_bug.cgi?id=57241