How to retrieve codec information using libvlc?

I need to get codec information when using libvlc to play remote media. Since the VLC player can achieve this(see the link below), libvlc may well do it too.

a screenshot of VLC

Also, I find that libvlc_media_tracks_get can retu a related struct as follows:

typedef struct libvlc_media_track_t
{
  /* Codec fourcc */
  uint32_t    i_codec;
  uint32_t    i_original_fourcc;
  int         i_id;
  libvlc_track_type_t i_type;

  /* Codec specific */
  int         i_profile;
  int         i_level;

  union {
      libvlc_audio_track_t *audio;
      libvlc_video_track_t *video;
      libvlc_subtitle_track_t *subtitle;
  };

  unsigned int i_bitrate;
  char *psz_language;
  char *psz_description;
} libvlc_media_track_t;

Maybe the member i_codec stores such information, but it's not human-readable and I don't know the meaning of a specific value. Probably there is a map between them and I haven't found it yet.