crate: ffmpeg43 feature flag (noop since 4.3.4) has been dropped from default features.

codec: deprecate APIs based on deprecated (since FFmpeg 3.1) avcodec_decode_video2() / avcodec_decode_audio4() / avcodec_encode_video2() /avcodec_encode_audio2() -- decoder::Video::decode(), decode::Audio::decode(), encoder::Video::encode() and encoder::Audio::decode(). Users should migrate to send_packet() / send_eof(), receive_frame(), send_frame() / send_eof(), and receive_packet() APIs instead, which are based on the modern send/receive APIs. See documentation in libavcodec/avcodec.h for details. (#28)

codec: fix signature of Packet::write_interleaved; previously Result<bool, Error>, now Result<(), Error>. (#25)

util: add util::log module to expose FFmpeg's logging facilities.

filter: add method Source::close() to expose av_buffersrc_close. (#23)

codec: add new encoding/decoding APIs send_frame() / send_eof(), receive_packet() to encoder::{Audio, Video} and send_packet() / send_eof(), receive_frame() to decoder::{Audio, Video} based on modern send/receive APIs (instead of avcodec_decode_video2() / avcodec_decode_audio4() / avcodec_encode_video2() /avcodec_encode_audio2() which have been deprecated since FFmpeg 3.1). Users should consider switching to the new APIs. See documentation in libavcodec/avcodec.h for details. (#28)

util: introduce new Error variant Error::Other { errno } for wrapped POSIX error codes (see the AVERROR macro in libavutil/error.h), and reexport common POSIX error codes under util::error. (#24)