-- 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