The AVCodecParameters weren't introduced until avcodec version 57.48.101
(FFmpeg version 3.1), so this will make sure to still use the older
avcodec_copy_context if the detected FFmpeg version is earlier.
(This commit also modifies the deps/media-playback, obs-ffmpeg, and
win-dshow modules)
More fixes due to ffmpeg renaming some constants and deprecating
AVFMT_RAWPICTURE and AV_PIX_FMT_VDA_VLD.
Latter replaced by AV_PIX_FMT_VIDEOTOOLBOX per ffmpeg dev advice.
Closesjp9000/obs-studio#1061