TODO:
- equalizer support to divx4, dshow
- vo_config callbacks to ffmpeg, cinepak
- better mpi support to xanim (now it's EXPORT but could be better)
- fix initial postprocessing flags (divx_quality)
- add common postprocessing filter support (export qscale array)
- IP buffering for NUV
- finish MPNG (8bpp support)
- IPB buffering to libmpeg2
- review authors

DONE:
#define VFM_CINEPAK 13
#define VFM_QTRPZA 20
#define VFM_FFMPEG 5
#define VFM_DSHOW 4
#define VFM_VFW 2
#define VFM_VFWEX 6
#define VFM_ODIVX 3
#define VFM_DIVX4 7
#define VFM_RAW 8
#define VFM_XANIM 10
#define VFM_RLE 9
#define VFM_MSVIDC 11
#define VFM_FLI 12
#define VFM_QTRLE 14
#define VFM_QTSMC 17
#define VFM_ROQVIDEO 19
#define VFM_CYUV 16
#define VFM_NUV 15
#define VFM_MPNG 21
#define VFM_MPEG 1