Address trac issue #378.

Signed-off-by: Martin Storsjö <martin@martin.st>

Beautify.

0 is top-field-first, 1 is bottom-field-first, not the other way
around.

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

Signed-off-by: Joakim Plate <elupus@ecce.se>
Signed-off-by: Anton Khirnov <anton@khirnov.net>

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

This is mainly useful for filters (like the sox synth), which
overwrite the content of the passed data.

The new syntax is more extensible and more user-friendly.

This breaks the previous syntax, should not be an issue as possibly
no-one is already using anullsrc.

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

Add aconvert filter to perform sample format, channel layout, and
packing format conversion.

The aconvert code depends on audio conversion code in libavcodec, so
this requires a dependency on libavcodec.

Based on previous work by S.N. Hemanth Meenakshisundaram and Mina Nagy
Zaki, performed for the GSoC 2010 and 2011.

Signed-off-by: Stefano Sabatini <stefasab@gmail.com>

Decoder and demuxer for various binary text formats.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

This list is mainly useful to be directly used as a parameter by the
audio sink buffer, when there is no need to force a specific channel
layout.

The list of formats is generated programmatically, and avoids channel
layouts not supported by libavfilter (with more than 8 channels).

We preferred to avoid compile-time generation in order to avoid some
unnecessary complexity (build hacks, generating code maintainance
etc.).

A more compact way to express this list through the use of macros
should be possible when libavfilter will support more than 8 channels,
as there will be no need to filter out channel layouts with more than
8 channels.

See thread:
Subject: [FFmpeg-devel] [PATCH] lavfi: add ff_all_channel_layouts internal symbol
Date: Sat, 20 Aug 2011 15:33:16 +0200

A function name should tell what the function does rather than what
the function returns. This also avoids possible conflicts
(e.g. between a function and a public list of all supported formats),
and clarifies the code.

Breaks audio API/ABI, add a backward compatibility layer for video
API/ABI.

It is not an API change.

Signed-off-by: Elvis Presley <elvis@e.p>

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

These changes were forgotten in commits:
  lavfi: simplify signature for avfilter_get_audio_buffer() and friends
  (commit 2c0317419b)
and
  lavfi: consistently use int for sample_rate in AVFilterLink and AVFilterBufferRefAudioProps
  (commit 4381bddc9f)

The additional parameters were never used and are complicating the
function interface. Also, they were inconsistent with the way the
video API works.

So this assumes that a requested samples buffer will have *always* the
format specified in the requested link.

This breaks audio filtering API and ABI.

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

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Also trim some redundant stream specifiers descriptions.

They are misleading and carry no useful information.

Add a per-stream -filter option, make -vf an alias for -filter:v. Move
vfilters to the options context.

It's redundant -- -flags +psnr does the same thing.

Also remove redundant -pix_fmt list syntax, it's inconsistent and  only
makes the code more complicated. -pix_fmts should be enough for
everyone.

Merge video_qscale (set by -qscale) and audio_qscale (set by -aq) into
one 'qscale' field in the options context. Add a shortcut -q for -qscale
and make -aq an alias for -q:a.

Also document it and replace undocumented and inconsistent
'-sample_fmt list' syntax with -sample_fmts.

The libavfilter SOC SVN repo is badly outdated, and some filters
supports a syntax different from the current code, so it is better do
not misled users into using it and just drop its reference.

In order to build C++ programs using libav you need
-D__STDC_CONSTANT_MACROS appened to the CXXFLAGS.