What an idiotic format. It makes no sense, and should have been
converted to S32 in the demuxer, rather than plague everyone with
another extremely obscure nonsense format. Why doesn't ffmpeg add S24
instead? That's an actually useful format.
May cause compilation failure with old FFmpeg or Libav libs, but I don't
care.
Although pretty similar to the probably unrelicensable
video/fmt-conversion.c/h (basically using the same idea, but for audio),
it was written by someone else. The format mapping was first added in
commit ad95e046c2.
It spams these in verbose mode. It's caused by format negotiation code
in af.c. It's for the mpv format to ffmpeg-format case, and that one is
very uninteresting. (The ffmpeg supported audio formats are practically
never extended.)
To make this easier, get rid of the direct mapping of the
AF_FORMAT_BITS_MASK bit field to number of bytes. This way we can throw
away the unused AF_FORMAT_48BIT and don't have to add ..._56BIT.
