The function is not implemented (and possibly useless).

The scale filter is used for internal colorspace conversions, so it must
always be present.

This is not an erroneous condition, do not print a warning.
Signed-off-by: Anton Khirnov <anton@khirnov.net>

Prevents it from referring to the rest of the list.

The user submitted variable in this function is frame, not buf.

This is required for letting applications to create and destroy
AVFilterInOut structs in a convenient way.
Signed-off-by: Anton Khirnov <anton@khirnov.net>

Right now, e.g. scale,[in]overlay would connect scale to the first
overlay input and [in] to the second, which goes against the
documentation and is unintuitive.

The bug happens because of the ordering mess in curr_inputs variable:
1) the unlabeled links from the previous filter are added to it in
correct order
2) input labels are parsed and inserted to the beginning one by one
(i.e. in reverse order)
3) curr_inputs is matched against filter inputs in reverse order

Fix the problem by always using proper ordering without trying to be
clever.

Unlike avfilter_graph_parse(), it returns unlinked inputs and outputs
to the caller, which allows parsing of graphs where inputs/outputs are
not known in advance.

Signal that it can output a frame when there are frames on the main
input and EOF on the overlay input, but a frame is buffered -- e.g.
single picture overlay.

This fixes the following warning:
libavfilter/vf_unsharp.c:106: warning: initialization discards qualifiers from pointer target type

I.e. just pass the buffer along when src parameters == dst parameters.

Current code, with a filterchain such as
(input - yuv411) -> (scale - any) -> (sink - any)
will result in yuv420 being chosen for the second link, which is clearly
not right.

This commit attempts to improve in the following way:
repeat until convergence:
  loop over all filters
    find input link with exactly one format
    force this format on all output links of the same type (if possible)

It will be used for logging, possibly also AVOptions.

This allows simplifying the Makefiles; it is no longer necessary to register
arch subdirectory Makefiles, just putting them in place is enough.

This makes it possible to dintinguish them from PAL8.

Fixes an invalid write in avpicture_layout().

Before, drawtext filter deliberately altered given text coordinates if
text didn't fully fit on the picture. This breaks the use case of
scrolling large text, e.g. movie closing credits.
Add 'fix_bounds', to make it usable in such cases (by setting its value to 0).
Default behavior is not changed, and non-fitting text coords are fixed.
Signed-off-by: Anton Khirnov <anton@khirnov.net>

Before, {text_,}{w,h} vars hadn't got initialized
Signed-off-by: Anton Khirnov <anton@khirnov.net>

Prevents uninitialized read.
Signed-off-by: Anton Khirnov <anton@khirnov.net>

Fixes several "‘static’ is not at beginning of declaration" warnings.

Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>