API changes, most recent first:
+2017-xx-xx - xxxxxxx - lavc 57.95.100 / 57.31.0 - avcodec.h
+ Add AVCodecContext.apply_cropping to control whether cropping
+ is handled by libavcodec or the caller.
+
+2017-xx-xx - xxxxxxx - lavu 55.62.100 / 55.30.0 - frame.h
+ Add AVFrame.crop_left/right/top/bottom fields for attaching cropping
+ information to video frames.
+
+2017-xx-xx - xxxxxxxxxx
+ Change av_sha_update(), av_sha512_update() and av_md5_sum()/av_md5_update() length
+ parameter type to size_t at next major bump.
+
+2017-05-05 - xxxxxxxxxx - lavc 57.94.100 - avcodec.h
+ The cuvid decoders now support AVCodecContext.hw_device_ctx, which removes
+ the requirement to set an incomplete AVCodecContext.hw_frames_ctx only to
+ set the Cuda device handle.
+
2017-04-11 - 8378466507 - lavu 55.61.100 - avstring.h
Add av_strireplace().