Never assume the API of libav* to be stable unless at least 1 week has passed since
the last major version increase.
The last version increases were:
libavcodec:  ?
libavcore:   2010-07-21
libavdevice: ?
libavfilter: 2009-10-18
libavformat: ?
libpostproc: ?
libswscale:  ?
libavutil:   2009-03-08


API changes, most recent first:

2011-01-07 - r26262 - lavc 52.107.0 - deprecate reordered_opaque
  Deprecate reordered_opaque in favor of pkt_pts/dts.

2011-01-07 - r26261 - lavc 52.106.0 - pkt_dts
  Add pkt_dts to AVFrame, this will in the future allow multithreading decoders
  to not mess up dts.

2011-01-07 - r26260 - lavc 52.105.0 - pkt_pts
  Add pkt_pts to AVFrame.

2011-01-XX - r26XXX - lavc 52.104.0 - av_get_profile_name()
  Add av_get_profile_name to libavcodec/avcodec.h.

2010-12-27 - r26108 - lavfi 1.71.0 - AV_PERM_NEG_LINESIZES
  Add AV_PERM_NEG_LINESIZES in avfilter.h.

2010-12-27 - r26104 - lavf 52.91.0 - av_find_best_stream()
  Add av_find_best_stream to libavformat/avformat.h.

2010-12-27 - r26103 - lavf 52.90.0
  Add AVFMT_NOSTREAMS flag for formats with no streams,
  like e.g. text metadata.

2010-12-22 - r26073 - lavu 50.36.0 - file.h
  Add functions av_file_map() and av_file_unmap() in file.h.

2010-12-19 - r26056 - lavu 50.35.0 - error.h
  Add "not found" error codes:
  AVERROR_DEMUXER_NOT_FOUND
  AVERROR_MUXER_NOT_FOUND
  AVERROR_DECODER_NOT_FOUND
  AVERROR_ENCODER_NOT_FOUND
  AVERROR_PROTOCOL_NOT_FOUND
  AVERROR_FILTER_NOT_FOUND
  AVERROR_BSF_NOT_FOUND
  AVERROR_STREAM_NOT_FOUND

2010-12-09 - r25923 - lavcore 0.16.0 - avcore.h
  Move AV_NOPTS_VALUE, AV_TIME_BASE, AV_TIME_BASE_Q symbols from
  avcodec.h to avcore.h.

2010-12-04 - r25886 - lavc 52.98.0 - CODEC_CAP_NEG_LINESIZES
  Add CODEC_CAP_NEG_LINESIZES codec capability flag in avcodec.h.

2010-12-04 - r25879 - lavu 50.34.0 - av_get_pix_fmt_string()
  Deprecate avcodec_pix_fmt_string() in favor of
  pixdesc.h/av_get_pix_fmt_string().

2010-12-04 - r25878 - lavcore 0.15.0 - av_image_alloc()
  Add av_image_alloc() to libavcore/imgutils.h.

2010-12-02 - r25862 - lavfi 1.67.0 - avfilter_graph_create_filter()
  Add function avfilter_graph_create_filter() in avfiltergraph.h.

2010-11-25 - r25826 - lavfi 1.65.0 - avfilter_get_video_buffer_ref_from_arrays()
  Add function avfilter_get_video_buffer_ref_from_arrays() in
  avfilter.h.

2010-11-21 - r25787 - lavcore 0.14.0 - audioconvert.h
  Add a public audio channel API in audioconvert.h, and deprecate the
  corresponding functions in libavcodec:
  avcodec_get_channel_name()
  avcodec_get_channel_layout()
  avcodec_get_channel_layout_string()
  avcodec_channel_layout_num_channels()
  and the CH_* macros defined in libavcodec/avcodec.h.

2010-11-21 - r25777 - lavf 52.85.0 - avformat.h
  Add av_append_packet().

2010-11-21 - r25776 - lavc 52.97.0 - avcodec.h
  Add av_grow_packet().

2010-11-17 - r25761 - lavcore 0.13.0 - parseutils.h
  Add av_parse_color() declared in libavcore/parseutils.h.

2010-11-13 - r25745 - lavc 52.95.0 - AVCodecContext
  Add AVCodecContext.subtitle_header and AVCodecContext.subtitle_header_size
  fields.

2010-11-13 - r25740 - lavfi 1.62.0 - avfiltergraph.h
  Make avfiltergraph.h public.

2010-11-13 - r25737 - lavfi 1.61.0 - avfiltergraph.h
  Remove declarations from avfiltergraph.h for the functions:
  avfilter_graph_check_validity()
  avfilter_graph_config_links()
  avfilter_graph_config_formats()
  which are now internal.
  Use avfilter_graph_config() instead.

2010-11-08 - r25708 - lavu 50.33.0 - eval.h
  Deprecate functions:
  av_parse_and_eval_expr(),
  av_parse_expr(),
  av_eval_expr(),
  av_free_expr(),
  in favor of the functions:
  av_expr_parse_and_eval(),
  av_expr_parse(),
  av_expr_eval(),
  av_expr_free().

2010-11-08 - r25707 - lavfi 1.59.0 - avfilter_free()
  Rename avfilter_destroy() to avfilter_free().
  This change breaks libavfilter API/ABI.

2010-11-07 - r25705 - lavfi 1.58.0 - avfiltergraph.h
  Remove graphparser.h header, move AVFilterInOut and
  avfilter_graph_parse() declarations to libavfilter/avfiltergraph.h.

2010-11-07 - r25700 - lavfi 1.57.0 - AVFilterInOut
  Rename field AVFilterInOut.filter to AVFilterInOut.filter_ctx.
  This change breaks libavfilter API.

2010-11-04 - r25674 - lavfi 1.56.0 - avfilter_graph_free()
  Rename avfilter_graph_destroy() to avfilter_graph_free().
  This change breaks libavfilter API/ABI.

2010-11-04 - r25673 - lavfi 1.55.0 - avfilter_graph_alloc()
  Add avfilter_graph_alloc() to libavfilter/avfiltergraph.h.

2010-11-02 - r25654 - lavcore 0.12.0 - av_get_bits_per_sample_fmt()
  Add av_get_bits_per_sample_fmt() to libavcore/samplefmt.h and
  deprecate av_get_bits_per_sample_format().

2010-11-02 - r25653 - lavcore 0.11.0 - samplefmt.h
  Add sample format functions in libavcore/samplefmt.h:
  av_get_sample_fmt_name(),
  av_get_sample_fmt(),
  av_get_sample_fmt_string(),
  and deprecate the corresponding libavcodec/audioconvert.h functions:
  avcodec_get_sample_fmt_name(),
  avcodec_get_sample_fmt(),
  avcodec_sample_fmt_string().

2010-11-02 - r25652 - lavcore 0.10.0 - samplefmt.h
  Define enum AVSampleFormat in libavcore/samplefmt.h, deprecate enum
  SampleFormat.

2010-10-16 - r25502 - lavfi 1.52.0 - avfilter_graph_config()
  Add the function avfilter_graph_config() in avfiltergraph.h.

2010-10-15 - r25493 - lavf 52.83.0 - metadata API
  Change demuxers to export metadata in generic format and
  muxers to accept generic format. Deprecate the public
  conversion API.

2010-10-10 - r25441 - lavfi 1.49.0 - AVFilterLink.time_base
  Add time_base field to AVFilterLink.

2010-09-27 - r25236 - lavu 50.31.0 - av_set_options_string()
  Move av_set_options_string() from libavfilter/parseutils.h to
  libavutil/opt.h.

2010-09-27 - r25227 - lavfi 1.47.0 - AVFilterLink
  Make the AVFilterLink fields srcpad and dstpad store the pointers to
  the source and destination pads, rather than their indexes.

2010-09-27 - r25225 - lavu 50.30.0 - av_get_token()
  Move av_get_token() from libavfilter/parseutils.h to
  libavutil/avstring.h.

2010-09-26 - r32368 - lsws 0.12.0 - swscale.h
  Add the functions sws_alloc_context() and sws_init_context().

2010-09-26 - r25210 - lavu 50.29.0 - opt.h
  Move libavcodec/opt.h to libavutil/opt.h.

2010-09-24 - r25174 - lavu 50.28.0 - av_log_set_flags()
  Default of av_log() changed due to many problems to the old no repeat
  detection. Read the docs of AV_LOG_SKIP_REPEATED in log.h before
  enabling it for your app!.

2010-09-24 - r25167 - lavc 52.90.0 - av_opt_show2()
  Deprecate av_opt_show() in favor or av_opt_show2().

2010-09-14 - r25120 - lavu 50.27.0 - av_popcount()
  Add av_popcount() to libavutil/common.h.

2010-09-08 - r25076 - lavu 50.26.0 - av_get_cpu_flags()
  Add av_get_cpu_flags().

2010-09-07 - r25067 - lavcore 0.9.0 - av_image_copy()
  Add av_image_copy().

2010-09-07 - r25064 - lavcore 0.8.0 - av_image_copy_plane()
  Add av_image_copy_plane().

2010-09-07 - r25057 - lavcore 0.7.0 - imgutils.h
  Adopt hierarchical scheme for the imgutils.h function names,
  deprecate the old names.

2010-09-04 - r25040 - lavu 50.25.0 - AV_CPU_FLAG_*
  Deprecate the FF_MM_* flags defined in libavcodec/avcodec.h in favor
  of the AV_CPU_FLAG_* flags defined in libavutil/cpu.h.

2010-08-26 - r24936 - lavc 52.87.0 - avcodec_get_channel_layout()
  Add avcodec_get_channel_layout() in audioconvert.h.

2010-08-20 - r24851 - lavcore 0.6.0 - av_fill_image_max_pixsteps()
  Rename av_fill_image_max_pixstep() to av_fill_image_max_pixsteps().

2010-08-18 - r24827 - lavcore 0.5.0 - av_fill_image_max_pixstep()
  Add av_fill_image_max_pixstep() in imgutils.h.

2010-08-17 - r24814 - lavu 50.24.0 - AV_NE()
  Add the AV_NE macro.

2010-08-17 - r24811 - lavfi 1.36.0 - audio framework
  Implement AVFilterBufferRefAudioProps struct for audio properties,
  get_audio_buffer(), filter_samples() functions and related changes.

2010-08-12 - r24787 - lavcore 0.4.0 - av_get_image_linesize()
  Add av_get_image_linesize() in imgutils.h.

2010-08-11 - r24773 - lavfi 1.34.0 - AVFilterBufferRef
  Resize data and linesize arrays in AVFilterBufferRef to 8.

  This change breaks libavfilter API/ABI.

2010-08-11 - r24768 - lavc 52.85.0 - av_picture_data_copy()
  Add av_picture_data_copy in avcodec.h.

2010-08-11 - r24765 - lavfi 1.33.0 - avfilter_open()
  Change avfilter_open() signature:
  AVFilterContext *avfilter_open(AVFilter *filter, const char *inst_name) ->
  int avfilter_open(AVFilterContext **filter_ctx, AVFilter *filter, const char *inst_name);

  This change breaks libavfilter API/ABI.

2010-08-11 - r24763 - lavfi 1.32.0 - AVFilterBufferRef
  Add a type field to AVFilterBufferRef, and move video specific
  properties to AVFilterBufferRefVideoProps.

  This change breaks libavfilter API/ABI.

2010-08-07 - r24732 - lavfi 1.31.0 - AVFilterLink
  Rename AVFilterLink fields:
  AVFilterLink.srcpic    ->  AVFilterLink.src_buf
  AVFilterLink.cur_pic   ->  AVFilterLink.cur_buf
  AVFilterLink.outpic    ->  AVFilterLink.out_buf

2010-08-07 - r24731 - lavfi 1.30.0
  Rename functions and fields:
  avfilter_(un)ref_pic       -> avfilter_(un)ref_buffer
  avfilter_copy_picref_props -> avfilter_copy_buffer_ref_props
  AVFilterBufferRef.pic      -> AVFilterBufferRef.buffer

2010-08-07 - r24730 - lavfi 1.29.0 - AVFilterBufferRef
  Rename AVFilterPicRef to AVFilterBufferRef.

2010-08-07 - r24728 - lavfi 1.28.0 - AVFilterBuffer
  Move format field from AVFilterBuffer to AVFilterPicRef.

2010-08-06 - r24709 - lavcore 0.3.0 - av_check_image_size()
  Deprecate avcodec_check_dimensions() in favor of the function
  av_check_image_size() defined in libavcore/imgutils.h.

2010-07-30 - r24592 - lavfi 1.27.0 - AVFilterBuffer
  Increase size of the arrays AVFilterBuffer.data and
  AVFilterBuffer.linesize from 4 to 8.

  This change breaks libavfilter ABI.

2010-07-29 - r24583 - lavcore 0.2.0 - imgutils.h
  Add functions av_fill_image_linesizes() and
  av_fill_image_pointers(), declared in libavcore/imgutils.h.

2010-07-27 - r24518 - lavcore 0.1.0 - parseutils.h
  Deprecate av_parse_video_frame_size() and av_parse_video_frame_rate()
  defined in libavcodec in favor of the newly added functions
  av_parse_video_size() and av_parse_video_rate() declared in
  libavcore/parseutils.h.

2010-07-23 - r24439 - lavu 50.23.0 - mathematics.h
  Add the M_PHI constant definition.

2010-07-22 - r24424 - lavfi 1.26.0 - media format generalization
  Add a type field to AVFilterLink.

  Change the field types:
  enum PixelFormat format   -> int format   in AVFilterBuffer
  enum PixelFormat *formats -> int *formats in AVFilterFormats
  enum PixelFormat *format  -> int format   in AVFilterLink

  Change the function signatures:
  AVFilterFormats *avfilter_make_format_list(const enum PixelFormat *pix_fmts); ->
  AVFilterFormats *avfilter_make_format_list(const int *fmts);

  int avfilter_add_colorspace(AVFilterFormats **avff, enum PixelFormat pix_fmt); ->
  int avfilter_add_format    (AVFilterFormats **avff, int fmt);

  AVFilterFormats *avfilter_all_colorspaces(void); ->
  AVFilterFormats *avfilter_all_formats    (enum AVMediaType type);

  This change breaks libavfilter API/ABI.

2010-07-21 - r24393 - lavcore 0.0.0
  Add libavcore.

2010-07-17 - r24291 - lavfi 1.25.0 - AVFilterBuffer
  Remove w and h fields from AVFilterBuffer.

2010-07-17 - r24284 - lavfi 1.24.0 - AVFilterBuffer
  Rename AVFilterPic to AVFilterBuffer.

2010-07-17 - r24278 - lavf 52.74.0 - url_fskip()
  Make url_fskip() return an int error code instead of void.

2010-07-11 - r24199 - lavc 52.83.0
  Add AVCodecContext.lpc_type and AVCodecContext.lpc_passes fields.
  Add AVLPCType enum.
  Deprecate AVCodecContext.use_lpc.

2010-07-11 - r24185 - lavc 52.82.0 - avsubtitle_free()
  Add a function for free the contents of a AVSubtitle generated by
  avcodec_decode_subtitle.

2010-07-11 - r24174 - lavu 50.22.0 - bswap.h and intreadwrite.h
  Make the bswap.h and intreadwrite.h API public.

2010-07-08 - r24101 - lavu 50.21.0 - pixdesc.h
  Rename read/write_line() to av_read/write_image_line().

2010-07-07 - r24091 - lavfi 1.21.0 - avfilter_copy_picref_props()
  Add avfilter_copy_picref_props().

2010-07-03 - r24021 - lavc 52.79.0
  Add FF_COMPLIANCE_UNOFFICIAL and change all instances of
  FF_COMPLIANCE_INOFFICIAL to use FF_COMPLIANCE_UNOFFICIAL.

2010-07-02 - r23985 - lavu 50.20.0 - lfg.h
  Export av_lfg_init(), av_lfg_get(), av_mlfg_get(), and av_bmg_get() through
  lfg.h.

2010-06-28 - r23835 - lavfi 1.20.1 - av_parse_color()
  Extend av_parse_color() syntax, make it accept an alpha value specifier and
  set the alpha value to 255 by default.

2010-06-22 - r23706 - lavf 52.71.0 - URLProtocol.priv_data_size, priv_data_class
  Add priv_data_size and priv_data_class to URLProtocol.

2010-06-22 - r23704 - lavf 52.70.0 - url_alloc(), url_connect()
  Add url_alloc() and url_connect().

2010-06-22 - r23702 - lavf 52.69.0 - av_register_protocol2()
  Add av_register_protocol2(), deprecating av_register_protocol().

2010-06-09 - r23551 - lavu 50.19.0 - av_compare_mod()
  Add av_compare_mod() to libavutil/mathematics.h.

2010-06-05 - r23485 - lavu 50.18.0 - eval API
  Make the eval API public.

2010-06-04 - r23461 - lavu 50.17.0 - AV_BASE64_SIZE
  Add AV_BASE64_SIZE() macro.

2010-06-02 - r23421 - lavc 52.73.0 - av_get_codec_tag_string()
  Add av_get_codec_tag_string().

2010-06-01 - r31301 - lsws 0.11.0 - convertPalette API
  Add sws_convertPalette8ToPacked32() and sws_convertPalette8ToPacked24().

2010-05-26 - r23334 - lavc 52.72.0 - CODEC_CAP_EXPERIMENTAL
  Add CODEC_CAP_EXPERIMENTAL flag.

2010-05-23 - r23255 - lavu 50.16.0 - av_get_random_seed()
  Add av_get_random_seed().

2010-05-18 - r23161 - lavf 52.63.0 - AVFMT_FLAG_RTP_HINT
  Add AVFMT_FLAG_RTP_HINT as possible value for AVFormatContext.flags.

2010-05-09 - r23066 - lavfi 1.20.0 - AVFilterPicRef
  Add interlaced and top_field_first fields to AVFilterPicRef.

2010-05-01 - r23002 - lavf 52.62.0 - probe function
  Add av_probe_input_format2 to API, it allows ignoring probe
  results below given score and returns the actual probe score.

2010-04-01 - r22806 - lavf 52.61.0 - metadata API
  Add a flag for av_metadata_set2() to disable overwriting of
  existing tags.

2010-04-01 - r22753 - lavc 52.66.0
  Add avcodec_get_edge_width().

2010-03-31 - r22750 - lavc 52.65.0
  Add avcodec_copy_context().

2010-03-31 - r22748 - lavf 52.60.0 - av_match_ext()
  Make av_match_ext() public.

2010-03-31 - r22736 - lavu 50.14.0 - AVMediaType
  Move AVMediaType enum from libavcodec to libavutil.

2010-03-31 - r22735 - lavc 52.64.0 - AVMediaType
  Define AVMediaType enum, and use it instead of enum CodecType, which
  is deprecated and will be dropped at the next major bump.

2010-03-25 - r22684 - lavu 50.13.0 - av_strerror()
  Implement av_strerror().

2010-03-23 - r22649 - lavc 52.60.0 - av_dct_init()
  Support DCT-I and DST-I.

2010-03-15 - r22540 - lavf 52.56.0 - AVFormatContext.start_time_realtime
  Add AVFormatContext.start_time_realtime field.

2010-03-13 - r22506 - lavfi 1.18.0 - AVFilterPicRef.pos
  Add AVFilterPicRef.pos field.

2010-03-13 - r22501 - lavu 50.12.0 - error.h
  Move error code definitions from libavcodec/avcodec.h to
  the new public header libavutil/error.h.

2010-03-07 - r22291 - lavc 52.56.0 - avfft.h
  Add public FFT interface.

2010-03-06 - r22251 - lavu 50.11.0 - av_stristr()
  Add av_stristr().

2010-03-03 - r22174 - lavu 50.10.0 - av_tree_enumerate()
  Add av_tree_enumerate().

2010-02-07 - r21673 - lavu 50.9.0 - av_compare_ts()
  Add av_compare_ts().

2010-02-05 - r30513 - lsws 0.10.0 - sws_getCoefficients()
  Add sws_getCoefficients().

2010-02-01 - r21587 - lavf 52.50.0 - metadata API
  Add a list of generic tag names, change 'author' -> 'artist',
  'year' -> 'date'.

2010-01-30 - r21545 - lavu 50.8.0 - av_get_pix_fmt()
  Add av_get_pix_fmt().

2010-01-21 - r30381 - lsws 0.9.0 - sws_scale()
  Change constness attributes of sws_scale() parameters.

2010-01-10 - r21121 - lavfi 1.15.0 - avfilter_graph_config_links()
  Add a log_ctx parameter to avfilter_graph_config_links().

2010-01-07 - r30236 - lsws 0.8.0 - sws_isSupported{In,Out}put()
  Add sws_isSupportedInput() and sws_isSupportedOutput() functions.

2010-01-06 - r21035 - lavfi 1.14.0 - avfilter_add_colorspace()
  Change the avfilter_add_colorspace() signature, make it accept an
  (AVFilterFormats **) rather than an (AVFilterFormats *) as before.

2010-01-03 - r21007 - lavfi 1.13.0 - avfilter_add_colorspace()
  Add avfilter_add_colorspace().

2010-01-02 - r20998 - lavf 52.46.0 - av_match_ext()
  Add av_match_ext(), it should be used in place of match_ext().

2010-01-01 - r20991 - lavf 52.45.0 - av_guess_format()
  Add av_guess_format(), it should be used in place of guess_format().

2009-12-13 - r20834 - lavf 52.43.0 - metadata API
  Add av_metadata_set2(), AV_METADATA_DONT_STRDUP_KEY and
  AV_METADATA_DONT_STRDUP_VAL.

2009-12-13 - r20829 - lavu 50.7.0 - avstring.h API
  Add av_d2str().

2009-12-13 - r20826 - lavc 52.42.0 - AVStream
  Add avg_frame_rate.

2009-12-12 - r20808 - lavu 50.6.0 - av_bmg_next()
  Introduce the av_bmg_next() function.

2009-12-05 - r20734 - lavfi 1.12.0 - avfilter_draw_slice()
  Add a slice_dir parameter to avfilter_draw_slice().

2009-11-26 - r20611 - lavfi 1.11.0 - AVFilter
  Remove the next field from AVFilter, this is not anymore required.

2009-11-25 - r20607 - lavfi 1.10.0 - avfilter_next()
  Introduce the avfilter_next() function.

2009-11-25 - r20605 - lavfi 1.9.0 - avfilter_register()
  Change the signature of avfilter_register() to make it return an
  int. This is required since now the registration operation may fail.

2009-11-25 - r20603 - lavu 50.5.0 - pixdesc.h API
  Make the pixdesc.h API public.

2009-10-27 - r20385 - lavfi 1.5.0 - AVFilter.next
  Add a next field to AVFilter, this is used for simplifying the
  registration and management of the registered filters.

2009-10-23 - r20356 - lavfi 1.4.1 - AVFilter.description
  Add a description field to AVFilter.

2009-10-19 - r20302 - lavfi 1.3.0 - avfilter_make_format_list()
  Change the interface of avfilter_make_format_list() from
  avfilter_make_format_list(int n, ...) to
  avfilter_make_format_list(enum PixelFormat *pix_fmts).

2009-10-18 - r20272 - lavfi 1.0.0 - avfilter_get_video_buffer()
  Make avfilter_get_video_buffer() recursive and add the w and h
  parameters to it.

2009-10-07 - r20189 - lavfi 0.5.1 - AVFilterPic
  Add w and h fields to AVFilterPic.

2009-06-22 - r19250 - lavf 52.34.1 - AVFormatContext.packet_size
  This is now an unsigned int instead of a signed int.

2009-06-19 - r19222 - lavc 52.32.0 - AVSubtitle.pts
  Add a pts field to AVSubtitle which gives the subtitle packet pts
  in AV_TIME_BASE. Some subtitle de-/encoders (e.g. XSUB) will
  not work right without this.

2009-06-03 - r19078 - lavc 52.30.2 - AV_PKT_FLAG_KEY
  PKT_FLAG_KEY has been deprecated and will be dropped at the next
  major version. Use AV_PKT_FLAG_KEY instead.

2009-06-01 - r19025 - lavc 52.30.0 - av_lockmgr_register()
  av_lockmgr_register() can be used to register a callback function
  that lavc (and in the future, libraries that depend on lavc) can use
  to implement mutexes. The application should provide a callback function
  that implements the AV_LOCK_* operations described in avcodec.h.
  When the lock manager is registered, FFmpeg is guaranteed to behave
  correctly in a multi-threaded application.

2009-04-30 - r18719 - lavc 52.28.0 - av_free_packet()
  av_free_packet() is no longer an inline function. It is now exported.

2009-04-11 - r18431 - lavc 52.25.0 - deprecate av_destruct_packet_nofree()
  Please use NULL instead. This has been supported since r16506
  (lavf > 52.23.1, lavc > 52.10.0).

2009-04-07 - r18351 - lavc 52.23.0 - avcodec_decode_video/audio/subtitle
  The old decoding functions are deprecated, all new code should use the
  new functions avcodec_decode_video2(), avcodec_decode_audio3() and
  avcodec_decode_subtitle2(). These new functions take an AVPacket *pkt
  argument instead of a const uint8_t *buf / int buf_size pair.

2009-04-03 - r18321 - lavu 50.3.0 - av_fifo_space()
  Introduce the av_fifo_space() function.

2009-04-02 - r18317 - lavc 52.23.0 - AVPacket
  Move AVPacket declaration from libavformat/avformat.h to
  libavcodec/avcodec.h.

2009-03-22 - r18163 - lavu 50.2.0 - RGB32 pixel formats
  Convert the pixel formats PIX_FMT_ARGB, PIX_FMT_RGBA, PIX_FMT_ABGR,
  PIX_FMT_BGRA, which were defined as macros, into enum PixelFormat values.
  Conversely PIX_FMT_RGB32, PIX_FMT_RGB32_1, PIX_FMT_BGR32 and
  PIX_FMT_BGR32_1 are now macros.
  avcodec_get_pix_fmt() now recognizes the "rgb32" and "bgr32" aliases.
  Re-sort the enum PixelFormat list accordingly.
  This change breaks API/ABI backward compatibility.

2009-03-22 - r18133 - lavu 50.1.0 - PIX_FMT_RGB5X5 endian variants
  Add the enum PixelFormat values:
  PIX_FMT_RGB565BE, PIX_FMT_RGB565LE, PIX_FMT_RGB555BE, PIX_FMT_RGB555LE,
  PIX_FMT_BGR565BE, PIX_FMT_BGR565LE, PIX_FMT_BGR555BE, PIX_FMT_BGR555LE.

2009-03-21 - r18116 - lavu 50.0.0  - av_random*
  The Mersenne Twister PRNG implemented through the av_random* functions
  was removed. Use the lagged Fibonacci PRNG through the av_lfg* functions
  instead.

2009-03-08 - r17869 - lavu 50.0.0  - AVFifoBuffer
  av_fifo_init, av_fifo_read, av_fifo_write and av_fifo_realloc were dropped
  and replaced by av_fifo_alloc, av_fifo_generic_read, av_fifo_generic_write
  and av_fifo_realloc2.
  In addition, the order of the function arguments of av_fifo_generic_read
  was changed to match av_fifo_generic_write.
  The AVFifoBuffer/struct AVFifoBuffer may only be used in an opaque way by
  applications, they may not use sizeof() or directly access members.

2009-03-01 - r17682 - lavf 52.31.0 - Generic metadata API
  Introduce a new metadata API (see av_metadata_get() and friends).
  The old API is now deprecated and should not be used anymore. This especially
  includes the following structure fields:
    - AVFormatContext.title
    - AVFormatContext.author
    - AVFormatContext.copyright
    - AVFormatContext.comment
    - AVFormatContext.album
    - AVFormatContext.year
    - AVFormatContext.track
    - AVFormatContext.genre
    - AVStream.language
    - AVStream.filename
    - AVProgram.provider_name
    - AVProgram.name
    - AVChapter.title
