API changes, most recent first:
+2016-xx-xx - xxxxxxx
+ Change av_sha_update() and av_md5_sum()/av_md5_update() length
+ parameter type to size_t at next major bump.
+
2016-xx-xx - xxxxxxx - lavc 57.29.0 - avcodec.h
Add AV_PKT_DATA_SPHERICAL packet side data to export AVSphericalMapping
information from containers.
Deprecate struct vaapi_context and the vaapi.h installed header.
Callers should set AVCodecContext.hw_frames_ctx instead.
+------------------------------8<-------------------------------------
+ 12 branch was cut here
+----------------------------->8--------------------------------------
+
2016-07-20 - xxxxxxx - lavu 55.20.0 - cpu.h
Add AV_CPU_FLAG_SSSE3SLOW.