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>

It can be used to directly pass a AVFilterBufferRef to lavfi, avoiding a
memcpy.

avfilter_copy_frame_props() avoids code duplication and increases
robustness.

The sample aspect ratio is a per-frame property, so it makes sense to
define it in AVFrame rather than in the codec/stream context.
Simplify application-level sample aspect ratio information extraction,
and allow further simplifications.

It's a part of public API.

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>

Signed-off-by: Mans Rullgard <mans@mansr.com>

It declares API necessary for filtering apps.

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

It slipped through the last two iterations.

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>

Introduce variables "E", "PHI", "PI", "main_w"/"W", "main_h"/"H",
"text_w"/"w", "text_h"/"h", "x", "y", "n" and "t" in line with
vf_overlay and refactor the code accordingly.

Call dtext_prepare_text as early as possible
Do not draw if the memory allocation failed

Split the memory allocation from the actual drawing.

It makes more sense for a bit mask to use an unsigned type.
The change should be source and binary compatible on all
supported systems, hence micro version bump.

Fixes a few invalid shifts.

Signed-off-by: Mans Rullgard <mans@mansr.com>

The licence was changed from GPL to LGPL with explicit approval from
the original author.

See thread:
Subject: [FFmpeg-devel] [PATCH] lavfi: add rgbtestsrc source,
        ported from MPlayer libmpcodecs
Date: Mon, 11 Jul 2011 16:32:41 +0200

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

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

The ported filter supports named option parsing and more YUV formats.

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

With the following additions:
* support to gray format
* support to yuva420p format
* parametric luma/chroma/alpha radius
* consistency check on the radius values, avoid crashes with invalid values

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