libavdevice: 2017-10-21
libavfilter: 2017-10-21
libavformat: 2017-10-21
-libavresample: 2017-10-21
libpostproc: 2017-10-21
libswresample: 2017-10-21
libswscale: 2017-10-21
API changes, most recent first:
+2021-04-27 - xxxxxxxxxx - lavc yyyyyyyyy - codec.h
+ avcodec_find_encoder_by_name(), avcodec_find_encoder(),
+ avcodec_find_decoder_by_name() and avcodec_find_decoder()
+ now return a pointer to const AVCodec.
+
+2021-04-27 - xxxxxxxxxx - lavf yyyyyyyyy - avformat.h
+ Constified AVFormatContext.*_codec.
+
2021-04-27 - xxxxxxxxxx - lavf yyyyyyyyy - avformat.h
Constified the pointers to AVInputFormats and AVOutputFormats
in AVFormatContext, avformat_alloc_output_context2(),