+- use of the new AVFrame crop fields in h264/hevc/theora (see https://ffmpeg.org/pipermail/ffmpeg-devel/2017-May/211239.html)
+ - a02ae1c683 hevcdec: export cropping information instead of handling it internally
+ - 4fded0480f h264dec: be more explicit in handling container cropping
+ - c3e84820d6 h264dec: export cropping information instead of handling it internally
+ - 1202b71269 theora: export cropping information instead of handling it internally