Channel coupling is an optional AC-3 feature that increases quality by
combining high frequency information from multiple channels into a
single channel. The per-channel high frequency information is sent with
less accuracy in both the frequency and time domains. This allows more
bits to be used for lower frequencies while preserving enough
information to reconstruct the high frequencies.
The new function accepts a slightly more intuitive order of paramters,
and returns an error code, thus allowing applications to report a
meaningful error message.
Make Audio Encoders a separate chapter, and decrese the contained
sections level by one.
Improve rendering, and improve consistency with the other parts of the
manual.
The new function is a wrapper around
av_vsrc_buffer_add_video_buffer_ref(), and allows to simplify the act
of pushing AVFrame data to the source buffer.
Adding _POSIX_C_SOURCE to CPPFLAGS globally produces all sorts of problems
since it causes certain system functions to be hidden on some (BSD) systems.
The solution is to only add the flag on systems that really require it, i.e.
glibc-based ones.
This change makes BSD systems compile out-of-the-box without the need for
adding specific flags manually. It also allows dropping a number of flags
set manually on a file-per-file basis, but were only present to work around
breakage introduced by the presence of _POSIX_C_SOURCE.
Also add _XOPEN_SOURCE to CPPFLAGS for glibc systems. We use XSI extensions
in several places already, so it is preferable to define it globally instead
of littering source files with individual #defines only needed for glibc.
The softfloat functionality is unused, not installed and incomplete.
On platforms without floating point units, the compiler provides a softfloat
implementation so there is no point in carrying this code around locally.
avfilter_copy_frame_props() avoids code duplication and increases
robustness.
The added files libavfilter/avcodec.[ch] are used for containing
utilities useful for gluing togheter libavfilter and libavcodec.
The format is a per-frame property, having it in AVFrame simplify the
operation of extraction of that information, since avoids the need to
access the codec/stream context.
width and height are per-frame properties, setting these values in
AVFrame simplify the operation of extraction of that information,
since avoids the need to check the codec/stream context.
With the following additions:
* support to anti-aliased glyph rendering
* support to UTF-8 text and Unicode chars rendering
* support for RGB packed formats
* fix minor errors and typos in the filter description
* extend/clarify examples in the filter description
Signed-off-by: Anton Khirnov <anton@khirnov.net>
Improve consistency with libavcodec.
This breaks libavfilter API/ABI.
The non-sequential 2.1.0 -> 2.4.0 bump is due to the mess previously
done with the lavfi minor number.
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.