[Libav-user] error avformat.h: avformat undeclared

[curer57458 at mypacks.net]

Hi libav user,

Where is AVFormat declared for the ffmpeg header file avformat.h found in /usr/include/libavformat/avformat.h? 

  libavutil      51. 34.101 / 51. 34.101
  libavcodec     53. 60.100 / 53. 60.100
  libavformat    53. 31.100 / 53. 31.100
  libavdevice    53.  4.100 / 53.  4.100
  libavfilter     2. 60.100 /  2. 60.100
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0.  6.100 /  0.  6.100
  libpostproc    52.  0.100 / 52.  0.100

The compilation error is from an application including the header file avformat.h:
error: ‘AVPacket’ was not declared in this scope

This error was also there with an older version of libavformat: 52 75 0.
A google search was not helpful in finding out where AVFormat is declared. Are there some CFLAGS that are needed to work with avformat.h, or what is missing? Also, the older version avformat.h 52 75 0 had the version defined in a MACRO and had a comment with swear words in it and "douchebag" while the newer version 53 31 100 did not.