APIchanges

Never assume the API of libav* to be stable unless at least 1 month has passed
since the last major version increase or the API was added.

The last version increases were:
libavcodec:    2013-03-xx
libavdevice:   2013-03-xx
libavfilter:   2012-06-22
libavformat:   2013-03-xx
libavresample: 2012-10-05
libpostproc:   2011-04-18
libswresample: 2011-09-19
libswscale:    2011-06-20
libavutil:     2012-10-22


API changes, most recent first:

2013-03-07 - xxxxxx - lavu 52.18.100 - avstring.h,bprint.h
  Add av_escape() and av_bprint_escape() API.

2013-02-24 - xxxxxx - lavfi 3.41.100 - buffersink.h
  Add sample_rates field to AVABufferSinkParams.

2013-01-17 - a1a707f - lavf 54.61.100
  Add av_codec_get_tag2().

2013-01-01 - 2eb2e17 - lavfi 3.34.100
  Add avfilter_get_audio_buffer_ref_from_arrays_channels.

2012-12-20 - 34de47aa - lavfi 3.29.100 - avfilter.h
  Add AVFilterLink.channels, avfilter_link_get_channels()
  and avfilter_ref_get_channels().

2012-12-15 - 2ada584d - lavc 54.80.100 - avcodec.h
  Add pkt_size field to AVFrame.

2012-11-25 - c70ec631 - lavu 52.9.100 - opt.h
  Add the following convenience functions to opt.h:
   av_opt_get_image_size
   av_opt_get_pixel_fmt
   av_opt_get_sample_fmt
   av_opt_set_image_size
   av_opt_set_pixel_fmt
   av_opt_set_sample_fmt

2012-11-17 - 4cd74c81 - lavu 52.8.100 - bprint.h
  Add av_bprint_strftime().

2012-11-15 - 92648107 - lavu 52.7.100 - opt.h
  Add av_opt_get_key_value().

2012-11-13 - 79456652 - lavfi 3.23.100 - avfilter.h
  Add channels field to AVFilterBufferRefAudioProps.

2012-11-03 - 481fdeee - lavu 52.3.100 - opt.h
  Add AV_OPT_TYPE_SAMPLE_FMT value to AVOptionType enum.

2012-10-21 - 6fb2fd8 - lavc  54.68.100 - avcodec.h
                       lavfi  3.20.100 - avfilter.h
  Add AV_PKT_DATA_STRINGS_METADATA side data type, used to transmit key/value
  strings between AVPacket and AVFrame, and add metadata field to
  AVCodecContext (which shall not be accessed by users; see AVFrame metadata
  instead).

2012-09-27 - a70b493 - lavd 54.3.100 - version.h
  Add LIBAVDEVICE_IDENT symbol.

2012-09-27 - a70b493 - lavfi 3.18.100 - version.h
  Add LIBAVFILTER_IDENT symbol.

2012-09-27 - a70b493 - libswr 0.16.100 - version.h
  Add LIBSWRESAMPLE_VERSION, LIBSWRESAMPLE_BUILD
  and LIBSWRESAMPLE_IDENT symbols.

2012-09-06 - 29e972f - lavu 51.72.100 - parseutils.h
  Add av_small_strptime() time parsing function.

  Can be used as a stripped-down replacement for strptime(), on
  systems which do not support it.

2012-08-25 - 2626cc4 - lavf 54.28.100
  Matroska demuxer now identifies SRT subtitles as AV_CODEC_ID_SUBRIP instead
  of AV_CODEC_ID_TEXT.

2012-08-13 - 5c0d8bc - lavfi 3.8.100 - avfilter.h
  Add avfilter_get_class() function, and priv_class field to AVFilter
  struct.

2012-08-12 - a25346e - lavu 51.69.100 - opt.h
  Add AV_OPT_FLAG_FILTERING_PARAM symbol in opt.h.

2012-07-31 - 23fc4dd - lavc 54.46.100
  Add channels field to AVFrame.

2012-07-30 - f893904 - lavu 51.66.100
  Add av_get_channel_description()
  and av_get_standard_channel_layout() functions.

2012-07-21 - 016a472 - lavc 54.43.100
  Add decode_error_flags field to AVFrame.

2012-07-20 - b062936 - lavf 54.18.100
  Add avformat_match_stream_specifier() function.

2012-07-14 - f49ec1b - lavc 54.38.100 - avcodec.h
  Add metadata to AVFrame, and the accessor functions
  av_frame_get_metadata() and av_frame_set_metadata().

2012-07-10 - 0e003d8 - lavc 54.33.100
  Add av_fast_padded_mallocz().

2012-07-10 - 21d5609 - lavfi 3.2.0 - avfilter.h
  Add init_opaque() callback to AVFilter struct.

2012-06-26 - e6674e4 - lavu 51.63.100 - imgutils.h
  Add functions to libavutil/imgutils.h:
  av_image_get_buffer_size()
  av_image_fill_arrays()
  av_image_copy_to_buffer()

2012-06-24 - c41899a - lavu 51.62.100 - version.h
  version moved from avutil.h to version.h

2012-04-11 - 359abb1 - lavu 51.58.100 - error.h
  Add av_make_error_string() and av_err2str() utilities to
  libavutil/error.h.

2012-06-05 - 62b39d4 - lavc 54.24.100
  Add pkt_duration field to AVFrame.

2012-05-24 - f2ee065 - lavu 51.54.100
  Move AVPALETTE_SIZE and AVPALETTE_COUNT macros from
  libavcodec/avcodec.h to libavutil/pixfmt.h.

2012-05-14 - 94a9ac1 - lavf 54.5.100
  Add av_guess_sample_aspect_ratio() function.

2012-04-20 - 65fa7bc - lavfi 2.70.100
  Add avfilter_unref_bufferp() to avfilter.h.

2012-04-13 - 162e400 - lavfi 2.68.100
  Install libavfilter/asrc_abuffer.h public header.

2012-03-26 - a67d9cf - lavfi 2.66.100
  Add avfilter_fill_frame_from_{audio_,}buffer_ref() functions.

2013-xx-xx - lavu 52.9.0 - pixdesc.h
  Add av_pix_fmt_count_planes() function for counting planes in a pixel format.

2013-xx-xx - lavfi 3.6.0
  Add AVFilterGraph.nb_filters, deprecate AVFilterGraph.filter_count.

2013-03-xx - Reference counted buffers - lavu 52.8.0, lavc 55.0.0, lavf 55.0.0,
lavd 54.0.0, lavfi 3.5.0
  xxxxxxx, xxxxxxx - add a new API for reference counted buffers and buffer
                     pools (new header libavutil/buffer.h).
  xxxxxxx - add AVPacket.buf to allow reference counting for the AVPacket data.
            Add av_packet_from_data() function for constructing packets from
            av_malloc()ed data.
  xxxxxxx - move AVFrame from lavc to lavu (new header libavutil/frame.h), add
            AVFrame.buf/extended_buf to allow reference counting for the AVFrame
            data. Add new API for working with reference-counted AVFrames.
  xxxxxxx - add the refcounted_frames field to AVCodecContext to make audio and
            video decoders return reference-counted frames. Add get_buffer2()
            callback to AVCodecContext which allocates reference-counted frames.
            Add avcodec_default_get_buffer2() as the default get_buffer2()
            implementation.
            Deprecate AVCodecContext.get_buffer() / release_buffer() /
            reget_buffer(), avcodec_default_get_buffer(),
            avcodec_default_reget_buffer(), avcodec_default_release_buffer().
            Remove avcodec_default_free_buffers(), which should not have ever
            been called from outside of lavc.
            Deprecate the following AVFrame fields:
                * base -- is now stored in AVBufferRef
                * reference, type, buffer_hints -- are unnecessary in the new API
                * hwaccel_picture_private, owner, thread_opaque -- should not
                  have been acessed from outside of lavc
                * qscale_table, qstride, qscale_type, mbskip_table, motion_val,
                  mb_type, dct_coeff, ref_index -- mpegvideo-specific tables,
                  which are not exported anymore.
  xxxxxxx - switch libavfilter to use AVFrame instead of AVFilterBufferRef. Add
            av_buffersrc_add_frame(), deprecate av_buffersrc_buffer().
            Add av_buffersink_get_frame() and av_buffersink_get_samples(),
            deprecate av_buffersink_read() and av_buffersink_read_samples().
            Deprecate AVFilterBufferRef and all functions for working with it.

2013-xx-xx - xxxxxxx - lavu 52.8.0 - avstring.h
  Add av_isdigit, av_isgraph, av_isspace, av_isxdigit.

2013-xx-xx - xxxxxxx - lavfi 3.4.0 - avfiltergraph.h
  Add resample_lavr_opts to AVFilterGraph for setting libavresample options
  for auto-inserted resample filters.

2013-xx-xx - xxxxxxx - lavu 52.7.0 - dict.h
  Add av_dict_parse_string() to set multiple key/value pairs at once from a
  string.

2013-01-xx - xxxxxxx - lavu 52.6.0 - avstring.h
  Add av_strnstr()