/* 
 * gdith.c --
 *
 *      Procedures dealing with grey-scale and mono dithering, 
 *      as well as X Windows set up procedures.
 *
 */

/*
 * Copyright (c) 1995 The Regents of the University of California.
 * All rights reserved.
 * 
 * Permission to use, copy, modify, and distribute this software and its
 * documentation for any purpose, without fee, and without written agreement is
 * hereby granted, provided that the above copyright notice and the following
 * two paragraphs appear in all copies of this software.
 * 
 * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR
 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
 * OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF
 * CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * 
 * THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
 * ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATION TO
 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
 */

/*
 * Portions of this software Copyright (c) 1995 Brown University.
 * All rights reserved.
 * 
 * Permission to use, copy, modify, and distribute this software and its
 * documentation for any purpose, without fee, and without written agreement
 * is hereby granted, provided that the above copyright notice and the
 * following two paragraphs appear in all copies of this software.
 * 
 * IN NO EVENT SHALL BROWN UNIVERSITY BE LIABLE TO ANY PARTY FOR
 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
 * OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF BROWN
 * UNIVERSITY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * 
 * BROWN UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS"
 * BASIS, AND BROWN UNIVERSITY HAS NO OBLIGATION TO PROVIDE MAINTENANCE,
 * SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
 */

#include <math.h>
#include "video.h"
#include "proto.h"
#include "dither.h"
#include "SDL_timer.h"

#include <stdlib.h>
#include <string.h>


/* 
   Changes to make the code reentrant:
      X variables now passed in xinfo: display, ximage,cmap,window, gc, etc
      De-globalized: ditherType, matched_depth, totNumFrames
      vid_stream->film_has_ended instead of FilmState

   Additional changes:
      Now can name and position each movie window individually
      DISABLE_DITHER cpp define - do not include dither code if defined
      NOFRAMECOUNT cpp define - do not count frames when running without
         controls
      Short circuit InitColorDisplay if not displaying anything
      ExistingWindow default now 0
   -lsh@cs.brown.edu (Loring Holden)
*/

/* Frame Rate Info */
extern int framerate;

/* Video rates table */
/* Cheat on Vid rates, round to 30, and use 30 if illegal value 
   Except for 9, where Xing means 15, and given their popularity, we'll
   be nice and do it */
static double VidRateNum[16]={ 30, 23.97, 24, 25, 29.97, 30, 50, 59.94, 
                            60, 15, 30, 30, 30, 15, 30, 30 };

#ifdef CALCULATE_FPS
static inline void TimestampFPS( VidStream* vid_stream )
{
    MPEGvideo* mpeg = (MPEGvideo*) vid_stream->_smpeg;

    vid_stream->frame_time[vid_stream->timestamp_index] = mpeg->Time();
    ++vid_stream->timestamp_index;
    if ( vid_stream->timestamp_index == FPS_WINDOW ) {
        vid_stream->timestamp_index = 0;
    }
}
#endif

/*
   Do frame rate control.  Returns _skipFrame
*/
#define LOOSE_MPEG_SCHEDULING
#ifdef LOOSE_MPEG_SCHEDULING
#define MAX_FRAME_SKIP  4
#define MAX_FUDGE_TIME  (MAX_FRAME_SKIP*vid_stream->_oneFrameTime)
#else
#ifdef TIGHT_MPEG_SCHEDULING
#define MAX_FRAME_SKIP  1
#define MAX_FUDGE_TIME  (MAX_FRAME_SKIP*vid_stream->_oneFrameTime)
#else
#define MAX_FRAME_SKIP  3
#define MAX_FUDGE_TIME  (MAX_FRAME_SKIP*vid_stream->_oneFrameTime)
#endif /* TIGHT_MPEG_SCHEDULING */
#endif /* LOOSE_MPEG_SCHEDULING */
#define FUDGE_TIME	(((MAX_FRAME_SKIP+1)/2)*vid_stream->_oneFrameTime)

/* This results in smoother framerate, but more dropped frames on
   systems that can play most of the video fine, but have problems
   with jerkiness in a few spots.
*/
//#define SLOW_START_SCHEDULING
#define SLOW_START_INCREMENT    0.3

/* Define this to debug the frame scheduler */
//#define DEBUG_MPEG_SCHEDULING

inline double CurrentTime( VidStream* vid_stream )
{
    MPEGvideo* mpeg = (MPEGvideo*) vid_stream->_smpeg;
    double now;

    if ( mpeg->TimeSource() ) {
        now = mpeg->TimeSource()->Time();
    } else {
        now = ReadSysClock() - vid_stream->realTimeStart;
    }
    return now;
}

int MPEGvideo::timeSync( VidStream* vid_stream )
{
    static double correction = -1;

    /* Update the number of frames displayed */
    vid_stream->totNumFrames++;
    vid_stream->current_frame++;

    /* Do we need to initialize framerate? */
    if ( vid_stream->rate_deal < 0 ) {
        switch( framerate ) {
          case -1: /* Go with stream Value */
            vid_stream->rate_deal = VidRateNum[ vid_stream->picture_rate ];
            break;

          case 0: /* as fast as possible */
            vid_stream->rate_deal = 0;
            break;

          default:
            vid_stream->rate_deal = framerate;
            break;
        }
        if ( vid_stream->rate_deal ) {
            vid_stream->_oneFrameTime = 1.0 / vid_stream->rate_deal;
        }
    }

    /* Update the current play time */
    play_time += vid_stream->_oneFrameTime;

    /* Synchronize using system timestamps */
    if(vid_stream->current && vid_stream->current->show_time > 0){
#ifdef DEBUG_TIMESTAMP_SYNC
      fprintf(stderr, "video: time:%.3f  shift:%.3f\r",
	      play_time,
	      play_time - vid_stream->current->show_time);
#endif
      if(correction == -1)
#ifdef STRANGE_SYNC_TEST
       /* this forces us to maintain the offset we have at the begining
          all the time, and is only usefull for testing */
        correction = play_time - vid_stream->current->show_time;
#else
       correction = 0;
#endif
#ifdef USE_TIMESTAMP_SYNC
      play_time = vid_stream->current->show_time + correction ;
#endif
      vid_stream->current->show_time = -1;
    }

    /* If we are looking for a particular frame... */
    if( vid_stream->_jumpFrame > -1 )
    {
        if ( vid_stream->totNumFrames != vid_stream->_jumpFrame ) {
            vid_stream->_skipFrame = 1;
        } else {
            vid_stream->_skipFrame = 0;
        }
        return vid_stream->_skipFrame;
    }

    /* If we're already behind, don't check timing */
    if ( vid_stream->_skipFrame > 0 )
    {
        return --vid_stream->_skipFrame;
    }

    /* See if we need to skip frames, based on timing */
    if ( vid_stream->rate_deal ) {
        static const double TIMESLICE = 0.01;   // Seconds per OS timeslice
        double time_behind;

        /* Calculate the frame time relative to real time */
        time_behind = CurrentTime(vid_stream) - Time();

#ifdef DEBUG_MPEG_SCHEDULING
printf("Frame %d: frame time: %f, real time: %f, time behind: %f\n", vid_stream->totNumFrames, Time(), CurrentTime(vid_stream), time_behind);
#endif

        /* Allow up to MAX_FUDGE_TIME of delay in output */
        if ( time_behind < -TIMESLICE ) {
            time_behind = -time_behind;
            vid_stream->_skipCount = 0;
#ifdef DEBUG_MPEG_SCHEDULING
printf("Ahead!  Sleeping %f\n", time_behind-TIMESLICE);
#endif
            SDL_Delay((Uint32)((time_behind-TIMESLICE)*1000));
        } else
        if ( time_behind < FUDGE_TIME ) {
            if ( vid_stream->_skipCount > 0 ) {
                vid_stream->_skipCount /= 2;
            }
#ifdef DEBUG_MPEG_SCHEDULING
printf("Just right.\n");
#endif
        } else
        if ( time_behind < MAX_FUDGE_TIME ) {
            if ( vid_stream->_skipCount > 0 ) {
                vid_stream->_skipCount--;
            }
            vid_stream->_skipFrame = 1+(int)(vid_stream->_skipCount/2);
#ifdef DEBUG_MPEG_SCHEDULING
printf("A little behind, skipping %d frames\n", vid_stream->_skipFrame);
#endif
        } else {
            /* time_behind >= MAX_FUDGE_TIME */
            if ( (time_behind > (MAX_FUDGE_TIME*2)) &&
                 (vid_stream->_skipCount == MAX_FRAME_SKIP) ) {
#ifdef DEBUG_MPEG_SCHEDULING
printf("Way too far behind, losing time sync...\n");
#endif
#if 0 // This results in smoother video, but sync's terribly on slow machines
                play_time = CurrentTime(vid_stream) - (MAX_FUDGE_TIME*2);
#endif
            }
#ifdef SLOW_START_SCHEDULING
            vid_stream->_skipCount += SLOW_START_INCREMENT;
#else
            vid_stream->_skipCount += 1.0;
#endif
            if( vid_stream->_skipCount > MAX_FRAME_SKIP ) {
                vid_stream->_skipCount = MAX_FRAME_SKIP;
            }
            vid_stream->_skipFrame = (int)(vid_stream->_skipCount+0.9);
#ifdef DEBUG_MPEG_SCHEDULING
printf("A lot behind, skipping %d frames\n", vid_stream->_skipFrame);
#endif
        }
    }
    return(vid_stream->_skipFrame);
}

/* Do the hard work of copying from the video stream working buffer to the
   screen display and then calling the update callback.
*/
void MPEGvideo::DisplayFrame( VidStream * vid_stream )
{
  Uint8 *image = (Uint8 *)vid_stream->current->image;
  size_t size = (_frame.image_width * _frame.image_height);

  /* Hold the lock while the frame is updated and callback are running */
  if ( _callback_lock )
    SDL_mutexP( _callback_lock );

  SDL_memcpy(_frame.image, image, size + (size/4) + (size/4));

  if ( _callback )
    _callback(_callback_data, &_frame);

  if ( _callback_lock )
    SDL_mutexV( _callback_lock );
}

/*
 *--------------------------------------------------------------
 *
 * ExecuteDisplay --
 *
 *	Actually displays display plane in previously created window.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Updates video frame timing control
 *
 *--------------------------------------------------------------
 */


void MPEGvideo::ExecuteDisplay( VidStream* vid_stream )
{
    if( ! vid_stream->_skipFrame )
    {
      DisplayFrame(vid_stream);

#ifdef CALCULATE_FPS
      TimestampFPS(vid_stream);
#endif
    }
    timeSync( vid_stream );
}

/* EOF */
