initial XvMC support, define common packet for decoder <-> libXvMC communication

Originally committed as revision 2086 to svn://svn.ffmpeg.org/ffmpeg/trunk

xvmc_render.h

+#include <X11/Xlib.h>
+#include <X11/Xutil.h>
+#include <X11/Xatom.h>
+#include <X11/extensions/Xv.h>
+#include <X11/extensions/Xvlib.h>
+#include <X11/extensions/XvMClib.h>
+
+
+//the surface should be shown, video driver manipulate this
+#define MP_XVMC_STATE_DISPLAY_PENDING 1
+//the surface is needed for prediction, codec manipulate this
+#define MP_XVMC_STATE_PREDICTION 2
+//                     1337    IDCT MCo
+#define MP_XVMC_RENDER_MAGIC 0x1DC711C0
+
+typedef   struct{
+//these are not changed by decoder!
+  int  magic;
+
+  short * data_blocks;
+  XvMCMacroBlock * mv_blocks;
+  int total_number_of_mv_blocks;
+  int total_number_of_data_blocks;
+  int mc_type;//XVMC_MPEG1/2/4,XVMC_H263 without XVMC_IDCT
+  int idct;//does we use IDCT acceleration?
+  int chroma_format;//420,422,444
+  int unsigned_intra;//+-128 for intra pictures after clip
+  int reserved1[13];//future extenstions (e.g. gmc,qpel)
+  XvMCSurface* p_surface;//pointer to rendered surface, never changed
+
+//these are changed by decoder
+//used by XvMCRenderSurface function
+  XvMCSurface* p_past_surface;//pointer to the past surface
+  XvMCSurface* p_future_surface;//pointer to  the future prediction surface
+
+  unsigned int picture_structure;//top/bottom fields or frame  !
+  unsigned int flags;//XVMC_SECOND_FIELD - 1'st or 2'd field in the sequence
+  unsigned int display_flags; //1,2 or 1+2 fields for XvMCPutSurface, 
+
+//these are internal communication one
+  int state;//0-free,1 Waiting to Display,2 Waiting for prediction
+  int start_mv_blocks_num;//offset in the array for the current slice,updated by vo
+  int filled_mv_blocks_num;//processed mv block in this slice,change by decoder
+  
+  int next_free_data_block_num;//used in add_mv_block, pointer to next free block
+
+} xvmc_render_state_t;