API changes, most recent first:
+2013-03-30 - xxxxxxx - lavu 52.24.100 - samplefmt.h
+ Add av_samples_alloc_array_and_samples().
+
+2013-03-29 - xxxxxxx - lavf 55.1.100 - avformat.h
+ Add av_guess_frame_rate()
+
2013-03-20 - xxxxxxx - lavu 52.22.100 - opt.h
Add AV_OPT_TYPE_DURATION value to AVOptionType enum.
2012-03-26 - a67d9cf - lavfi 2.66.100
Add avfilter_fill_frame_from_{audio_,}buffer_ref() functions.
+2013-xx-xx - lavfi 3.8.0
+ Move all content from avfiltergraph.h to avfilter.h. Deprecate
+ avfilterhraph.h, user applications should include just avfilter.h
+
+2013-xx-xx - lavfi 3.7.0 - avfilter.h
+ Add AVFilter.priv_class for exporting filter options through the AVOptions API
+ in the similar way private options work in lavc and lavf.
+ Add avfilter_get_class().
+ Switch all filters to use AVOptions.
+
2013-xx-xx - lavu 52.9.0 - pixdesc.h
Add av_pix_fmt_count_planes() function for counting planes in a pixel format.