Release Notes
=============

* 9 "Plain Nine"

General notes
-------------

From this release onwards, we have decided to drop the leading zero from our
release numbers. There were no plans of ever changing it, so it carried no
information. Thus this release is just a plain 9, the next will be 10 etc.

A new library arrived in Libav during this development cycle -- its name is
libavresample and it handles audio conversion and mixing. All users are
encouraged to use it instead of the old, now deprecated, audio conversion
API in libavcodec.

The libpostproc library now resides in a separate tree. It was fully independent
of the other Libav libraries, not used by any of the tools and saw very little
development. For these reasons we decided that it has no place in Libav. A
standalone Git tree is available at http://git.videolan.org/?p=libpostproc.git
for people wishing to use libpostproc.

The major versions of the libavcodec, libavformat and libavfilter libraries have
been bumped, so they are not API or ABI compatible with the 0.8 release. The
ffmpeg transcoding tool, kept for compatibility in 0.8, has also been dropped.

This release brings a number of significant changes in the libavfilter library.
Firstly, all the API dealing with filter internals is no longer public. The
result is that creating user-side filters will not be supported until
libavfilter is more mature.
Secondly, full audio filtering support is now available along with a set of
basic audio filters. We hope that their number will soon grow significantly.
The avconv transcoding tool has of course been extended to handle audio
filtering as well.
There were a number of other API changes, most importantly the addition of
the buffer sink public API.

In the libavcodec library, one of the most notable changes is added support for
planar audio (i.e. not interleaved). Many decoders and encoders, that previously
did inefficient (de)interleaving internally, now only work with planar audio
formats. Libavresample can be used for optimized conversion between interleaved
and planar formats.

Of big interest to our Windows users, Libav now supports building with the MSVC
compiler. Since MSVC does not support C99 features used extensively by Libav,
this has been accomplished using a converter that turns C99 code to C89. See the
platform-specific documentation for more detailed documentation on building
Libav with MSVC.

As usual, this release also contains support for some new formats, many smaller
new features and countless bug fixes. We can highlight Opus decoding / encoding
through libopus, encoders for Apple ProRes and Ut Video, WMA Lossless and
RealAudio Lossless decoders, fragmented MOV/MP4 and ISMV (Smooth Streaming)
muxers, 24-bit FLAC encoding, a large number of RTMP improvements and support
for cover art in ID3v2, WMA, MP4 and FLAC.

See the Changelog file for a list of significant changes.

Please note that our policy on bug reports has not changed. We still only accept
bug reports against HEAD of the Libav trunk repository. If you are experiencing
issues with any formally released version of Libav, please try a current version
of the development code to check if the issue still exists. If it does, make
your report against the development code following the usual bug reporting
guidelines.


API changes
-----------

A number of additional APIs have been introduced and some existing functions
have been deprecated and are scheduled for removal in the next release.
Significant API changes include:

[libavcodec]:
* New video encoding API, similar to the previously introduced audio  encoding
  API, which encodes from an AVFrame to an AVPacket, thus allowing it to
  properly output timing information and side data.

* All CODEC_ID_* symbols now carry AV_ prefixes. Non-prefixed codec IDs are
  deprecated.

* New codec descriptor API, which allows getting the properties of a given codec
  (identified by its ID), without referring to a specific decoder or encoder.

* An AVFrame must now be freed with a dedicated function, avcodec_free_frame().

[libavutil]:
* New audio FIFO API, which simplifies managing/merging/splitting audio buffers.

* new int/float type punning API

[libavfilter]:
* All filter internals were hidden.

* audio filtering.

* new buffer sink API for getting frames out of libavfilter.

Please see the file doc/APIchanges for details along with similar
programmer-centric information.