/*
 * The contents of this file are subject to the Mozilla Public
 * License Version 1.1 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.mozilla.org/MPL/
 * 
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 * 
 * The Original Code is MPEG4IP.
 * 
 * The Initial Developer of the Original Code is Cisco Systems Inc.
 * Portions created by Cisco Systems Inc. are
 * Copyright (C) Cisco Systems Inc. 2004.  All Rights Reserved.
 * 
 * Contributor(s): 
 *		Bill May wmay@cisco.com
 */

/*
 * mpeg2ps.c - parse program stream and vob files
 */
#include "mpeg2_ps.h"

#ifndef GPAC_DISABLE_MPEG2PS


static GFINLINE u16 convert16 (u8 *p)
{
#ifdef GPAC_BIG_ENDIAN
  return *(u16 *)p;
#else
  u16 val = p[0];
  val <<= 8;
  return (val | p[1]);
#endif
}

static GFINLINE u32 convert32 (u8 *p)
{
#ifdef GPAC_BIG_ENDIAN
  return *(u32 *)p;
#else
  u32 val;
  val = p[0]; val <<= 8;
  val |= p[1]; val <<= 8;
  val |= p[2]; val <<= 8;
  val |= p[3];
  return val;
#endif
}

#define FDNULL 0

/*
 * structure for passing timestamps around
 */
typedef struct mpeg2ps_ts_t
{
  Bool have_pts;
  Bool have_dts;
  u64 pts;
  u64 dts;
} mpeg2ps_ts_t;

typedef struct mpeg2ps_record_pes_t
{
  struct mpeg2ps_record_pes_t *next_rec;
  u64 dts;
  u64 location;
} mpeg2ps_record_pes_t;

/*
 * information about reading a stream
 */
typedef struct mpeg2ps_stream_t 
{
  mpeg2ps_record_pes_t *record_first, *record_last;
  FILE *m_fd;
  Bool is_video;
  u8 m_stream_id;    // program stream id
  u8 m_substream_id; // substream, for program stream id == 0xbd

  mpeg2ps_ts_t next_pes_ts, frame_ts;
  u32 frames_since_last_ts;
  u64 last_ts;

  Bool have_frame_loaded;
  /*
   * pes_buffer processing.  this contains the raw elementary stream data
   */
  u8 *pes_buffer;
  u32 pes_buffer_size;
  u32 pes_buffer_size_max;
  u32 pes_buffer_on;
  u32 frame_len;
  u32 pict_header_offset; // for mpeg video

  // timing information and locations.
  s64 first_pes_loc;
  u64 start_dts;
  Bool first_pes_has_dts;
  s64    end_dts_loc;
  u64 end_dts;
  // audio stuff
  u32 freq;
  u32 channels;
  u32 bitrate;
  u32 samples_per_frame;
  u32 layer;
  // video stuff
  u32 h, w, par;
  Double frame_rate;
  s32 have_mpeg2;
  Double bit_rate;
  u64 ticks_per_frame;

} mpeg2ps_stream_t;

/*
 * main interface structure - contains stream pointers and other
 * information
 */
struct mpeg2ps_ {
  mpeg2ps_stream_t *video_streams[16];
  mpeg2ps_stream_t *audio_streams[32];
  char *filename;
  FILE *fd;
  u64 first_dts;
  u32 audio_cnt, video_cnt;
  s64 end_loc;
  u64 max_dts;
  u64 max_time;  // time is in msec.
};

/*************************************************************************
 * File access routines.  Could all be inlined
 *************************************************************************/
static FILE *file_open (const char *name)
{
  return gf_f64_open(name, "rb");
}

static Bool file_okay (FILE *fd)
{
	return (fd!=NULL) ? 1 : 0;
}

static void file_close (FILE *fd)
{
  fclose(fd);
}

static Bool file_read_bytes(FILE *fd,
			     u8 *buffer, 
			     u32 len)
{
  u32 readval = fread(buffer, 1, len, fd);
  return readval == len;
}

// note: len could be negative.
static void file_skip_bytes (FILE *fd, s32 len)
{
  gf_f64_seek(fd, len, SEEK_CUR);
}

#define file_location(__f) gf_f64_tell(__f)
#define file_seek_to(__f, __off) gf_f64_seek(__f, __off, SEEK_SET)

static u64 file_size(FILE *fd)
{
  u64 ret;
  gf_f64_seek(fd, 0, SEEK_END);
  ret = gf_f64_tell(fd);
  gf_f64_seek(fd, 0, SEEK_SET);
  return ret;
}

static mpeg2ps_record_pes_t *create_record (s64 loc, u64 ts)
{
  mpeg2ps_record_pes_t *ret;
  GF_SAFEALLOC(ret, mpeg2ps_record_pes_t);

  ret->next_rec = NULL;
  ret->dts = ts;
  ret->location = loc;
  return ret;
}

#define MPEG2PS_RECORD_TIME ((u64) (5 * 90000))
void mpeg2ps_record_pts (mpeg2ps_stream_t *sptr, s64 location, mpeg2ps_ts_t *pTs)
{
  u64 ts;
  mpeg2ps_record_pes_t *p, *q;
  if (sptr->is_video) {
    if (pTs->have_dts == 0) return;
    ts = pTs->dts;
  } else {
    if (pTs->have_pts == 0) return;
    ts = pTs->pts;
  }

  if (sptr->record_first == NULL) {
    sptr->record_first = sptr->record_last = create_record(location, ts);
    return;
  } 
  if (ts > sptr->record_last->dts) {
    if (ts < MPEG2PS_RECORD_TIME + sptr->record_last->dts) return;
    sptr->record_last->next_rec = create_record(location, ts);
	sptr->record_last = sptr->record_last->next_rec;
    return;
  }
  if (ts < sptr->record_first->dts) {
    if (ts < MPEG2PS_RECORD_TIME + sptr->record_first->dts) return;
    p = create_record(location, ts);
    p->next_rec = sptr->record_first;
    sptr->record_first = p;
    return;
  }
  p = sptr->record_first;
  q = p->next_rec;

  while (q != NULL && q->dts < ts) {
    p = q;
    q = q->next_rec;
  }
  if (p->dts + MPEG2PS_RECORD_TIME <= ts &&
      ts + MPEG2PS_RECORD_TIME <= q->dts) {
    p->next_rec = create_record(location, ts);
    p->next_rec->next_rec = q;
  }
}
static Double mpeg12_frame_rate_table[16] =
{
  0.0,   /* Pad */
  24000.0/1001.0,       /* Official frame rates */
  24.0,
  25.0,
  30000.0/1001.0,
  30.0,
  50.0,
  ((60.0*1000.0)/1001.0),
  60.0,

  1,                    /* Unofficial economy rates */
  5, 
  10,
  12,
  15,
  0,
  0,
};

#define SEQ_ID 1
int MPEG12_ParseSeqHdr(unsigned char *pbuffer, u32 buflen, s32 *have_mpeg2, u32 *height, u32 *width, 
								  Double *frame_rate, Double *bitrate, u32 *aspect_ratio)
{
  u32 aspect_code;
  u32 framerate_code;
  u32 bitrate_int;
  u32 bitrate_ext;
  u32 scode, ix;
  s32 found = -1;
  *have_mpeg2 = 0;
  buflen -= 6;
  bitrate_int = 0;
  for (ix = 0; ix < buflen; ix++, pbuffer++) {
    scode = (pbuffer[0] << 24) | (pbuffer[1] << 16) | (pbuffer[2] << 8) | 
      pbuffer[3];

    if (scode == MPEG12_SEQUENCE_START_CODE) {
      pbuffer += sizeof(u32);
      *width = (pbuffer[0]);
      *width <<= 4;
      *width |= ((pbuffer[1] >> 4) &0xf);
      *height = (pbuffer[1] & 0xf);
      *height <<= 8;
      *height |= pbuffer[2];
      aspect_code = (pbuffer[3] >> 4) & 0xf;
      if (aspect_ratio != NULL) {
		  u32 par = 0;
			switch (aspect_code) {
			default: *aspect_ratio = 0; break;
			case 2: par = 4; par<<=16; par |= 3; break;
			case 3: par = 16; par<<=16; par |= 9; break;
			case 4: par = 2; par<<=16; par |= 21; break;
			}
			*aspect_ratio = par;
      }
	  
	
      framerate_code = pbuffer[3] & 0xf;
      *frame_rate = mpeg12_frame_rate_table[framerate_code];
      // 18 bits
      bitrate_int = (pbuffer[4] << 10) | 
	(pbuffer[5] << 2) | 
	((pbuffer[6] >> 6) & 0x3);
      *bitrate = bitrate_int;
      *bitrate *= 400.0;
      ix += sizeof(u32) + 7;
      pbuffer += 7;
      found = 0;
    } else if (found == 0) {
      if (scode == MPEG12_EXT_START_CODE) {
	pbuffer += sizeof(u32);
	ix += sizeof(u32);
	switch ((pbuffer[0] >> 4) & 0xf) {
	case SEQ_ID:
	  *have_mpeg2 = 1;
	  *height = ((pbuffer[1] & 0x1) << 13) | 
	    ((pbuffer[2] & 0x80) << 5) |
	    (*height & 0x0fff);
	  *width = (((pbuffer[2] >> 5) & 0x3) << 12) | (*width & 0x0fff);
	  bitrate_ext = (pbuffer[2] & 0x1f) << 7;
	  bitrate_ext |= (pbuffer[3] >> 1) & 0x7f;
	  bitrate_int |= (bitrate_ext << 18);
	  *bitrate = bitrate_int;
	  *bitrate *= 400.0;
	  break;
	default:
	  break;
	}
	pbuffer++;
	ix++;
      } else if (scode == MPEG12_PICTURE_START_CODE) {
	return found;
      }
    }
  }
  return found;
}


s32 MPEG12_PictHdrType (unsigned char *pbuffer)
{
  pbuffer += sizeof(u32);
  return ((pbuffer[1] >> 3) & 0x7);
}

u16 MPEG12_PictHdrTempRef(unsigned char *pbuffer)
{
  pbuffer += sizeof(u32);
  return ((pbuffer[0] << 2) | ((pbuffer[1] >> 6) & 0x3));
}


static u64 read_pts (u8 *pak)
{
  u64 pts;
  u16 temp;
  
  pts = ((pak[0] >> 1) & 0x7);
  pts <<= 15;
  temp = convert16(&pak[1]) >> 1;
  pts |= temp;
  pts <<= 15;
  temp = convert16(&pak[3]) >> 1;
  pts |= temp;
  return pts;
}


static mpeg2ps_stream_t *mpeg2ps_stream_create (u8 stream_id,
						u8 substream)
{
  mpeg2ps_stream_t *ptr;
  GF_SAFEALLOC(ptr, mpeg2ps_stream_t);
  ptr->m_stream_id = stream_id;
  ptr->m_substream_id = substream;
  ptr->is_video = stream_id >= 0xe0;
  ptr->pes_buffer = (u8 *)gf_malloc(4*4096);
  ptr->pes_buffer_size_max = 4 * 4096;
  return ptr;
}

static void mpeg2ps_stream_destroy (mpeg2ps_stream_t *sptr)
{
  mpeg2ps_record_pes_t *p;
  while (sptr->record_first != NULL) {
    p = sptr->record_first;
    sptr->record_first = p->next_rec;
    gf_free(p);
  }
  if (sptr->m_fd != FDNULL) {
    file_close(sptr->m_fd);
    sptr->m_fd = FDNULL;
  }
  if (sptr->pes_buffer) gf_free(sptr->pes_buffer);
  gf_free(sptr);
}


/*
 * adv_past_pack_hdr - read the pack header, advance past it
 * we don't do anything with the data
 */
static void adv_past_pack_hdr (FILE *fd, 
			       u8 *pak,
			       u32 read_from_start)
{
  u8 stuffed;
  u8 readbyte;
  u8 val;
  if (read_from_start < 5) {
    file_skip_bytes(fd, 5 - read_from_start);
    file_read_bytes(fd, &readbyte, 1);
    val = readbyte;
  } else {
    val = pak[4];
  }
    
  // we've read 6 bytes
  if ((val & 0xc0) != 0x40) {
    // mpeg1
    file_skip_bytes(fd, 12 - read_from_start); // skip 6 more bytes
    return;
  }
  file_skip_bytes(fd, 13 - read_from_start);
  file_read_bytes(fd, &readbyte, 1);
  stuffed = readbyte & 0x7;
  file_skip_bytes(fd, stuffed);
}

/*
 * find_pack_start
 * look for the pack start code in the file - read 512 bytes at a time, 
 * searching for that code.
 * Note: we may also be okay looking for >= 00 00 01 bb
 */
static Bool find_pack_start (FILE *fd, 
			     u8 *saved,
			     u32 len)
{
  u8 buffer[512];
  u32 buffer_on = 0, new_offset, scode;
  memcpy(buffer, saved, len);
  if (file_read_bytes(fd, buffer + len, sizeof(buffer) - len) == 0) {
    return 0;
  }
  while (1) {
    if (gf_mv12_next_start_code(buffer + buffer_on,
				 sizeof(buffer) - buffer_on, 
				 &new_offset, 
				 &scode) >= 0) {
      buffer_on += new_offset;
      if (scode == MPEG2_PS_PACKSTART) {
	file_skip_bytes(fd, buffer_on - 512); // go back to header
	return 1;
      }
      buffer_on += 1;
    } else {
      len = 0;
      if (buffer[sizeof(buffer) - 3] == 0 &&
	  buffer[sizeof(buffer) - 2] == 0 &&
	  buffer[sizeof(buffer) - 1] == 1) {
	buffer[0] = 0;
	buffer[1] = 0;
	buffer[2] = 1;
	len = 3;
      } else if (*(u16 *)(buffer + sizeof(buffer) - 2) == 0) {
	buffer[0] = 0;
	buffer[1] = 0;
	len = 2;
      } else if (buffer[sizeof(buffer) - 1] == 0) {
	buffer[0] = 0;
	len = 1;
      }
      if (file_read_bytes(fd, buffer + len, sizeof(buffer) - len) == 0) {
	return 0;
      }
      buffer_on = 0;
    }
  }
  return 0;
}

/*
 * copy_bytes_to_pes_buffer - read pes_len bytes into the buffer, 
 * adjusting it if we need it
 */
static void copy_bytes_to_pes_buffer (mpeg2ps_stream_t *sptr, 
			       u16 pes_len)
{
  u32 to_move;

  if (sptr->pes_buffer_size + pes_len > sptr->pes_buffer_size_max) {
    // if no room in the buffer, we'll move it - otherwise, just fill
    // note - we might want a better strategy about moving the buffer - 
    // right now, we might be moving a number of bytes if we have a large
    // followed by large frame.
    to_move = sptr->pes_buffer_size - sptr->pes_buffer_on;
    memmove(sptr->pes_buffer,
	    sptr->pes_buffer + sptr->pes_buffer_on,
	    to_move);
    sptr->pes_buffer_size = to_move;
    sptr->pes_buffer_on = 0;
    //fprintf(stderr, "moving %d bytes\n", to_move);
    if (to_move + pes_len > sptr->pes_buffer_size_max) {
      sptr->pes_buffer = (u8 *)gf_realloc(sptr->pes_buffer, 
					    to_move + pes_len + 2048);
      sptr->pes_buffer_size_max = to_move + pes_len + 2048;
    }
  }
  file_read_bytes(sptr->m_fd, sptr->pes_buffer + sptr->pes_buffer_size, pes_len);
  sptr->pes_buffer_size += pes_len;
#if 0
  fprintf(stderr, "copying %u bytes - on %u size %u\n",
	 pes_len, sptr->pes_buffer_on, sptr->pes_buffer_size);
#endif
}

/*
 * read_to_next_pes_header - read the file, look for the next valid
 * pes header.  We will skip over PACK headers, but not over any of the
 * headers listed in 13818-1, table 2-18 - basically, anything with the
 * 00 00 01 and the next byte > 0xbb.
 * We return the pes len to read, and the "next byte"
 */
static Bool read_to_next_pes_header (FILE *fd, 
				     u8 *stream_id,
				     u16 *pes_len)
{
  u32 hdr;
  u8 local[6];

  while (1) {
    // read the pes header
    if (file_read_bytes(fd, local, 6) == 0) {
      return 0;
    }

    hdr = convert32(local);
    // if we're not a 00 00 01, read until we get the next pack start
    // we might want to also read until next PES - look into that.
    if (((hdr & MPEG2_PS_START_MASK) != MPEG2_PS_START) ||
	(hdr < MPEG2_PS_END)) {
      if (find_pack_start(fd, local, 6) == 0) {
	return 0;
      }
      continue;
    }
    if (hdr == MPEG2_PS_PACKSTART) {
      // pack start code - we can skip down
      adv_past_pack_hdr(fd, local, 6);
      continue;
    }
    if (hdr == MPEG2_PS_END) {
      file_skip_bytes(fd, -2);
      continue;
    }

    // we should have a valid stream and pes_len here...
    *stream_id = hdr & 0xff;
    *pes_len = convert16(local + 4);
#if 0
    fprintf(stderr, "loc: "X64" %x len %u\n", file_location(fd) - 6,
	   local[3],
	   *pes_len);
#endif
    return 1;
  }
  return 0;
}

/*
 * read_pes_header_data
 * this should read past the pes header for the audio and video streams
 * it will store the timestamps if it reads them
 */
static Bool read_pes_header_data (FILE *fd, 
				  u16 orig_pes_len,
				  u16 *pes_left,
				  Bool *have_ts,
				  mpeg2ps_ts_t *ts)
{
  u16 pes_len = orig_pes_len;
  u8 local[10];
  u32 hdr_len;

  ts->have_pts = 0;
  ts->have_dts = 0;
  *have_ts = 0;
  if (file_read_bytes(fd, local, 1) == 0) {
    return 0;
  }
  pes_len--; // remove this first byte from length
  while (*local == 0xff) {
    if (file_read_bytes(fd, local, 1) == 0) {
      return 0;
    }
    pes_len--;
    if (pes_len == 0) {
      *pes_left = 0;
      return 1;
    }
  }
  if ((*local & 0xc0) == 0x40) { 
    // buffer scale & size
    file_skip_bytes(fd, 1);
    if (file_read_bytes(fd, local, 1) == 0) {
      return 0;
    }
    pes_len -= 2;
  }

  if ((*local & 0xf0) == 0x20) {
    // mpeg-1 with pts
    if (file_read_bytes(fd, local + 1, 4) == 0) {
      return 0;
    }
    ts->have_pts = 1;
    ts->pts = ts->dts = read_pts(local);
    //fprintf(stderr, "mpeg1 pts "U64"\n", ts->pts);
    *have_ts = 1;
    pes_len -= 4;
  } else if ((*local & 0xf0) == 0x30) {
    // have mpeg 1 pts and dts
    if (file_read_bytes(fd, local + 1, 9) == 0) {
      return 0;
    }
    ts->have_pts = 1;
    ts->have_dts = 1;
    *have_ts = 1;
    ts->pts = read_pts(local);
    ts->dts = read_pts(local + 5);
    pes_len -= 9;
  } else if ((*local & 0xc0) == 0x80) {
    // mpeg2 pes header  - we're pointing at the flags field now
    if (file_read_bytes(fd, local + 1, 2) == 0) {
      return 0;
    }
    hdr_len = local[2];
    pes_len -= hdr_len + 2; // first byte removed already
    if ((local[1] & 0xc0) == 0x80) {
      // just pts
      ts->have_pts = 1;
      file_read_bytes(fd, local, 5);
      ts->pts = ts->dts = read_pts(local);
      *have_ts = 1;
      hdr_len -= 5;
    } else if ((local[1] & 0xc0) == 0xc0) {
      // pts and dts
      ts->have_pts = 1;
      ts->have_dts = 1;
      *have_ts = 1;
      file_read_bytes(fd, local, 10);
      ts->pts = read_pts(local);
      ts->dts = read_pts(local  + 5);    
      hdr_len -= 10;
    }
    file_skip_bytes(fd, hdr_len);
  } else if (*local != 0xf) {
    file_skip_bytes(fd, pes_len);
    pes_len = 0;
  } 
  *pes_left = pes_len;
  return 1;
}

static Bool search_for_next_pes_header (mpeg2ps_stream_t *sptr, 
					u16 *pes_len,
					Bool *have_ts, 
					s64 *found_loc)
{
  u8 stream_id;
  u8 local;
  s64 loc;
  while (1) {
    // this will read until we find the next pes.  We don't know if the
    // stream matches - this will read over pack headers
    if (read_to_next_pes_header(sptr->m_fd, &stream_id, pes_len) == 0) {
      return 0;
    }

    if (stream_id != sptr->m_stream_id) {
      file_skip_bytes(sptr->m_fd, *pes_len);
      continue;
    }
    loc = file_location(sptr->m_fd) - 6; 
    // advance past header, reading pts
    if (read_pes_header_data(sptr->m_fd, 
			     *pes_len, 
			     pes_len, 
			     have_ts, 
			     &sptr->next_pes_ts) == 0) {
      return 0;
    }

    // If we're looking at a private stream, make sure that the sub-stream
    // matches.
    if (sptr->m_stream_id == 0xbd) {
      // ac3 or pcm
      file_read_bytes(sptr->m_fd, &local, 1);
      *pes_len -= 1;
      if (local != sptr->m_substream_id) {
	file_skip_bytes(sptr->m_fd, *pes_len);
	continue; // skip to the next one
      }
      *pes_len -= 3;
      file_skip_bytes(sptr->m_fd, 3); // 4 bytes - we don't need now...
      // we need more here...
    }
    if (have_ts) {
      mpeg2ps_record_pts(sptr, loc, &sptr->next_pes_ts);
    }
    if (found_loc != NULL) *found_loc = loc;
    return 1;
  }
  return 0;
}

/*
 * mpeg2ps_stream_read_next_pes_buffer - for the given stream, 
 * go forward in the file until the next PES for the stream is read.  Read
 * the header (pts, dts), and read the data into the pes_buffer pointer
 */
static Bool mpeg2ps_stream_read_next_pes_buffer (mpeg2ps_stream_t *sptr)
{
  u16 pes_len;
  Bool have_ts;

  if (search_for_next_pes_header(sptr, &pes_len, &have_ts, NULL) == 0) {
    return 0;
  }

  copy_bytes_to_pes_buffer(sptr, pes_len);

  return 1;
}


/***************************************************************************
 * Frame reading routine.  For each stream, the fd's should be different.
 * we will read from the pes stream, and save it in the stream's pes buffer.
 * This will give us raw data that we can search through for frame headers, 
 * and the like.  We shouldn't read more than we need - when we need to read, 
 * we'll put the whole next pes buffer in the buffer
 *
 * Audio routines are of the format:
 *   look for header
 *   determine length
 *   make sure length is in buffer
 *
 * Video routines
 *   look for start header (GOP, SEQ, Picture)
 *   look for pict header
 *   look for next start (END, GOP, SEQ, Picture)
 *   
 ***************************************************************************/
#define IS_MPEG_START(a) ((a) == 0xb3 || (a) == 0x00 || (a) == 0xb8)

static Bool 
mpeg2ps_stream_find_mpeg_video_frame (mpeg2ps_stream_t *sptr)
{
  u32 offset, scode;
  Bool have_pict;
  Bool started_new_pes = 0;
  u32 start;
  /*
   * First thing - determine if we have enough bytes to read the header.
   * if we do, we have the correct timestamp.  If not, we read the new
   * pes, so we'd want to use the timestamp we read.
   */
  sptr->frame_ts = sptr->next_pes_ts; 
  if (sptr->pes_buffer_size <= sptr->pes_buffer_on + 4) {
    if (sptr->pes_buffer_size != sptr->pes_buffer_on)
      started_new_pes = 1;
    if (mpeg2ps_stream_read_next_pes_buffer(sptr) == 0) {
      return 0;
    }
  }
  while (gf_mv12_next_start_code(sptr->pes_buffer + sptr->pes_buffer_on, 
				  sptr->pes_buffer_size - sptr->pes_buffer_on,
				  &offset,
				  &scode) < 0 ||
	 (!IS_MPEG_START(scode & 0xff))) {
    if (sptr->pes_buffer_size > 3)
      sptr->pes_buffer_on = sptr->pes_buffer_size - 3;
    else {
      sptr->pes_buffer_on = sptr->pes_buffer_size;
      started_new_pes = 1;
    }
    if (mpeg2ps_stream_read_next_pes_buffer(sptr) == 0) {
      return 0;
    }
  }
  sptr->pes_buffer_on += offset;
  if (offset == 0 && started_new_pes) {
    // nothing...  we've copied the timestamp already.
  } else {
    // we found the new start, but we pulled in a new pes header before
    // starting.  So, we want to use the header that we read.
    sptr->frame_ts = sptr->next_pes_ts; // set timestamp after searching
    // clear timestamp indication
    sptr->next_pes_ts.have_pts = sptr->next_pes_ts.have_dts = 0;
  }
#if 0
  fprintf(stderr, "header %x at %d\n", scode, sptr->pes_buffer_on);
#endif

  if (scode == MPEG12_PICTURE_START_CODE) {
    sptr->pict_header_offset = sptr->pes_buffer_on;
    have_pict = 1;
  } else have_pict = 0;

  start = 4 + sptr->pes_buffer_on;
  while (1) {
    
    if (gf_mv12_next_start_code(sptr->pes_buffer + start, 
				 sptr->pes_buffer_size - start,
				 &offset,
				 &scode) < 0) {
      start = sptr->pes_buffer_size - 3;
      start -= sptr->pes_buffer_on;
      sptr->pict_header_offset -= sptr->pes_buffer_on;
      if (mpeg2ps_stream_read_next_pes_buffer(sptr) == 0) {
	return 0;
      }
      start += sptr->pes_buffer_on;
      sptr->pict_header_offset += sptr->pes_buffer_on;
    } else {
#if 0
      fprintf(stderr, "2header %x at %d\n", scode, start);
#endif

      start += offset;
      if (have_pict == 0) {
	if (scode == MPEG12_PICTURE_START_CODE) {
	  have_pict = 1;
	  sptr->pict_header_offset = start;
	}
      } else {
	if (IS_MPEG_START(scode & 0xff) ||
	    scode == MPEG12_SEQUENCE_END_START_CODE) {
	  sptr->frame_len = start - sptr->pes_buffer_on;
	  sptr->have_frame_loaded = 1;
	  return 1;
	}
      }
      start += 4;
    }
  }
  return 0;
}

static Bool mpeg2ps_stream_find_ac3_frame (mpeg2ps_stream_t *sptr)
{
  u32 diff;
  GF_AC3Header hdr;
  Bool started_new_pes = 0;
  sptr->frame_ts = sptr->next_pes_ts; // set timestamp after searching
  if (sptr->pes_buffer_size <= sptr->pes_buffer_on + 6) {
    if (sptr->pes_buffer_size != sptr->pes_buffer_on)
      started_new_pes = 1;
    if (mpeg2ps_stream_read_next_pes_buffer(sptr) == 0) {
      return 0;
    }
  }
  while (gf_ac3_parser(sptr->pes_buffer + sptr->pes_buffer_on,
			      sptr->pes_buffer_size - sptr->pes_buffer_on,
			       &diff, 
			      &hdr, 0) <= 0) {
    // don't have frame
    if (sptr->pes_buffer_size > 6) {
      sptr->pes_buffer_on = sptr->pes_buffer_size - 6;
      started_new_pes = 1;
    } else {
      sptr->pes_buffer_on = sptr->pes_buffer_size;
    }
    if (mpeg2ps_stream_read_next_pes_buffer(sptr) == 0) {
      return 0;
    }
  }
  sptr->frame_len = hdr.framesize;
  sptr->pes_buffer_on += diff;
  if (diff == 0 && started_new_pes) {
    // we might have a new PTS - but it's not here
  } else {
    sptr->frame_ts = sptr->next_pes_ts;
    sptr->next_pes_ts.have_dts = sptr->next_pes_ts.have_pts = 0;
  }
  while (sptr->pes_buffer_size - sptr->pes_buffer_on < sptr->frame_len) {
#if 0
    fprintf(stderr, "don't have enough - on %u size %u %u %u\n", sptr->pes_buffer_on, 
	   sptr->pes_buffer_size,
	   sptr->pes_buffer_size - sptr->pes_buffer_on, 
	   sptr->frame_len);
#endif
    if (mpeg2ps_stream_read_next_pes_buffer(sptr) == 0) {
      return 0;
    }
  }
  sptr->have_frame_loaded = 1;
  return 1;
}

static Bool mpeg2ps_stream_find_mp3_frame (mpeg2ps_stream_t *sptr)
{
  u32 diff, hdr;
  Bool started_new_pes = 0;

  sptr->frame_ts = sptr->next_pes_ts;
  if (sptr->pes_buffer_size <= sptr->pes_buffer_on + 4) {
    if (sptr->pes_buffer_size != sptr->pes_buffer_on)
      started_new_pes = 1;
    if (mpeg2ps_stream_read_next_pes_buffer(sptr) == 0) {
      return 0;
    }
  }
  while ((hdr=gf_mp3_get_next_header_mem((char*)sptr->pes_buffer + sptr->pes_buffer_on,
			sptr->pes_buffer_size - sptr->pes_buffer_on,
			&diff) ) == 0) {
    // don't have frame
    if (sptr->pes_buffer_size > 3) {
      if (sptr->pes_buffer_on != sptr->pes_buffer_size) {
	sptr->pes_buffer_on = sptr->pes_buffer_size - 3;
      }
      started_new_pes = 1; // we have left over bytes...
    } else {
      sptr->pes_buffer_on = sptr->pes_buffer_size;
    }
    if (mpeg2ps_stream_read_next_pes_buffer(sptr) == 0) {
      return 0;
    }
  }
  // have frame.
  sptr->frame_len = gf_mp3_frame_size(hdr);
  sptr->pes_buffer_on += diff;
  if (diff == 0 && started_new_pes) {

  } else {
    sptr->frame_ts = sptr->next_pes_ts;
    sptr->next_pes_ts.have_dts = sptr->next_pes_ts.have_pts = 0;
  }
  while (sptr->pes_buffer_size - sptr->pes_buffer_on < sptr->frame_len) {
#if 0
    fprintf(stderr, "don't have enough - on %u size %u %u %u\n", sptr->pes_buffer_on, 
	   sptr->pes_buffer_size,
	   sptr->pes_buffer_size - sptr->pes_buffer_on, 
	   sptr->frame_len);
#endif
    if (mpeg2ps_stream_read_next_pes_buffer(sptr) == 0) {
      return 0;
    }
  }
  sptr->have_frame_loaded = 1;
  return 1;
}

/*
 * mpeg2ps_stream_read_frame.  read the correct frame based on stream type.
 * advance_pointers is 0 when we want to use the data
 */
static Bool mpeg2ps_stream_read_frame (mpeg2ps_stream_t *sptr,
				       u8 **buffer, 
				       u32 *buflen,
				       Bool advance_pointers)
{
  //  Bool done = 0;
  if (sptr->is_video) {
    if (mpeg2ps_stream_find_mpeg_video_frame(sptr)) {
      *buffer = sptr->pes_buffer + sptr->pes_buffer_on;
      *buflen = sptr->frame_len;
      if (advance_pointers) {
	sptr->pes_buffer_on += sptr->frame_len;
      }
      return 1;
    }
    return 0;
  } else if (sptr->m_stream_id == 0xbd) {
    // would need to handle LPCM here
    if (mpeg2ps_stream_find_ac3_frame(sptr)) {
      *buffer = sptr->pes_buffer + sptr->pes_buffer_on;
      *buflen = sptr->frame_len;
      if (advance_pointers)
	sptr->pes_buffer_on += sptr->frame_len;
      return 1;
    }
    return 0;
  } else if (mpeg2ps_stream_find_mp3_frame(sptr)) {
    *buffer = sptr->pes_buffer + sptr->pes_buffer_on;
    *buflen = sptr->frame_len;
    if (advance_pointers)
      sptr->pes_buffer_on += sptr->frame_len;
    return 1;
  }
  return 0;
}

/*
 * get_info_from_frame - we have a frame, get the info from it.
 */
static void get_info_from_frame (mpeg2ps_stream_t *sptr, 
				 u8 *buffer, 
				 u32 buflen)
{
  if (sptr->is_video) {
    if (MPEG12_ParseSeqHdr(buffer, buflen,
			       &sptr->have_mpeg2,
			       &sptr->h,
			       &sptr->w,
			       &sptr->frame_rate,
			       &sptr->bit_rate,
			       &sptr->par) < 0) {
      sptr->m_stream_id = 0;
      sptr->m_fd = FDNULL;
    }
    sptr->ticks_per_frame = (u64)(90000.0 / sptr->frame_rate);
    return;
  }

  if (sptr->m_stream_id >= 0xc0) {
    // mpeg audio
    u32 hdr = GF_4CC(buffer[0],buffer[1],buffer[2],buffer[3]);

    sptr->channels = gf_mp3_num_channels(hdr);
    sptr->freq = gf_mp3_sampling_rate(hdr);
    sptr->samples_per_frame = gf_mp3_window_size(hdr);
    sptr->bitrate = gf_mp3_bit_rate(hdr) * 1000; // give bps, not kbps
    sptr->layer = gf_mp3_layer(hdr);
  } else if (sptr->m_stream_id == 0xbd) {
    if (sptr->m_substream_id >= 0xa0) {
      // PCM - ???
    } else if (sptr->m_substream_id >= 0x80) {
		u32 pos;
		GF_AC3Header hdr;
      gf_ac3_parser(buffer, buflen, &pos, &hdr, 0);
	  sptr->bitrate = hdr.bitrate;
	  sptr->freq = hdr.sample_rate;
	  sptr->channels = hdr.channels;
      sptr->samples_per_frame = 256 * 6;
    } else {
      return;
    }
  } else {
    return;
  }
}

/*
 * clear_stream_buffer - called when we seek to clear out any data in 
 * the buffers
 */
static void clear_stream_buffer (mpeg2ps_stream_t *sptr)
{
  sptr->pes_buffer_on = sptr->pes_buffer_size = 0;
  sptr->frame_len = 0;
  sptr->have_frame_loaded = 0;
  sptr->next_pes_ts.have_dts = sptr->next_pes_ts.have_pts = 0;
  sptr->frame_ts.have_dts = sptr->frame_ts.have_pts = 0;
}

/*
 * convert_to_msec - convert ts (at 90000) to msec, based on base_ts and
 * frames_since_last_ts.
 */
static u64 convert_ts (mpeg2ps_stream_t *sptr,
			    mpeg2ps_ts_type_t ts_type,
			    u64 ts,
			    u64 base_ts,
			    u32 frames_since_ts)
{
  u64 ret, calc;
  ret = ts - base_ts;
  if (sptr->is_video) {
    // video
    ret += frames_since_ts * sptr->ticks_per_frame;
  } else {
    // audio
    calc = (frames_since_ts * 90000 * sptr->samples_per_frame) / sptr->freq;
    ret += calc;
  }
  if (ts_type == TS_MSEC)
    ret /= (u64) (90); // * 1000 / 90000

  return ret;
}

/*
 * find_stream_from_id - given the stream, get the sptr.
 * only used in inital set up, really.  APIs use index into 
 * video_streams and audio_streams arrays.
 */
static mpeg2ps_stream_t *find_stream_from_id (mpeg2ps_t *ps, 
					      u8 stream_id, 
					      u8 substream)
{
  u8 ix;
  if (stream_id >= 0xe0) {
    for (ix = 0; ix < ps->video_cnt; ix++) {
      if (ps->video_streams[ix]->m_stream_id == stream_id) {
	return ps->video_streams[ix];
      }
    }
  } else {
    for (ix = 0; ix < ps->audio_cnt; ix++) {
      if (ps->audio_streams[ix]->m_stream_id == stream_id &&
	  (stream_id != 0xbd ||
	   substream == ps->audio_streams[ix]->m_substream_id)) {
	return ps->audio_streams[ix];
      }
    }
  }
  return NULL;
}

/*
 * add_stream - add a new stream
 */
static Bool add_stream (mpeg2ps_t *ps,
			u8 stream_id,
			u8 substream,
			s64 first_loc,
			mpeg2ps_ts_t *ts)
{
  mpeg2ps_stream_t *sptr;
  
  sptr = find_stream_from_id(ps, stream_id, substream);
  if (sptr != NULL) return 0;

  // need to add

  sptr = mpeg2ps_stream_create(stream_id, substream);
  sptr->first_pes_loc = first_loc;
  if (ts == NULL ||
      (ts->have_dts == 0 && ts->have_pts == 0)) {
    sptr->first_pes_has_dts = 0;
  } else {
    sptr->start_dts = ts->have_dts ? ts->dts : ts->pts;
    sptr->first_pes_has_dts = 1;
  }
  if (sptr->is_video) {
    // can't be more than 16 - e0 to ef...
    ps->video_streams[ps->video_cnt] = sptr;
    ps->video_cnt++;
  } else {
    if (ps->audio_cnt >= 32) {
      mpeg2ps_stream_destroy(sptr);
      return 0;
    }
    ps->audio_streams[ps->audio_cnt] = sptr;
    ps->audio_cnt++;
  }
  return 1;
}

static void check_fd_for_stream (mpeg2ps_t *ps, 
			  mpeg2ps_stream_t *sptr)
{
  if (sptr->m_fd != FDNULL) return;

  sptr->m_fd = file_open(ps->filename);
}

/*
 * advance_frame - when we're reading frames, this indicates that we're
 * done.  We will call this when we read a frame, but not when we
 * seek.  It allows us to leave the last frame we're seeking in the
 * buffer
 */
static void advance_frame (mpeg2ps_stream_t *sptr)
{
  sptr->pes_buffer_on += sptr->frame_len;
  sptr->have_frame_loaded = 0;
  if (sptr->frame_ts.have_dts || sptr->frame_ts.have_pts) {
    if (sptr->frame_ts.have_dts) 
      sptr->last_ts = sptr->frame_ts.dts;
    else
      sptr->last_ts = sptr->frame_ts.pts;
    sptr->frames_since_last_ts = 0;
  } else {
    sptr->frames_since_last_ts++;
  }
}
/*
 * get_info_for_all_streams - loop through found streams - read an
 * figure out the info
 */
static void get_info_for_all_streams (mpeg2ps_t *ps)
{
  u8 stream_ix, max_ix, av;
  mpeg2ps_stream_t *sptr;
  u8 *buffer;
  u32 buflen;

	file_seek_to(ps->fd, 0);

  // av will be 0 for video streams, 1 for audio streams
  // av is just so I don't have to dup a lot of code that does the
  // same thing.
  for (av = 0; av < 2; av++) {
    if (av == 0) max_ix = ps->video_cnt;
    else max_ix = ps->audio_cnt;
    for (stream_ix = 0; stream_ix < max_ix; stream_ix++) {
      if (av == 0) sptr = ps->video_streams[stream_ix];
      else sptr = ps->audio_streams[stream_ix];

      // we don't open a seperate file descriptor yet (only when they
      // start reading or seeking).  Use the one from the ps.
      sptr->m_fd = ps->fd; // for now
      clear_stream_buffer(sptr);
      if (mpeg2ps_stream_read_frame(sptr,
				    &buffer, 
				    &buflen,
				    0) == 0) {
	sptr->m_stream_id = 0;
	sptr->m_fd = FDNULL;
	continue;
      }
      get_info_from_frame(sptr, buffer, buflen);
      // here - if (sptr->first_pes_has_dts == 0) should be processed
      if (sptr->first_pes_has_dts == 0) {
	u32 frames_from_beg = 0;
	Bool have_frame;
	do {
	  advance_frame(sptr);
	  have_frame = 
	    mpeg2ps_stream_read_frame(sptr, &buffer, &buflen, 0);
	  frames_from_beg++;
	} while (have_frame && 
		 sptr->frame_ts.have_dts == 0 && 
		 sptr->frame_ts.have_pts == 0 && 
		 frames_from_beg < 1000);
	if (have_frame == 0 ||
	    (sptr->frame_ts.have_dts == 0 &&
	     sptr->frame_ts.have_pts == 0)) {
	} else {
	  sptr->start_dts = sptr->frame_ts.have_dts ? sptr->frame_ts.dts : 
	    sptr->frame_ts.pts;
	  if (sptr->is_video) {
	    sptr->start_dts -= frames_from_beg * sptr->ticks_per_frame;
	  } else {
	    u64 conv;
	    conv = sptr->samples_per_frame * 90000;
	    conv /= (u64)sptr->freq;
	    sptr->start_dts -= conv;
	  }
	}
      }
      clear_stream_buffer(sptr);
      sptr->m_fd = FDNULL;
    }
  }
}

/*
 * mpeg2ps_scan_file - read file, grabbing all the information that
 * we can out of it (what streams exist, timing, etc).
 */
static void mpeg2ps_scan_file (mpeg2ps_t *ps)
{
  u8 stream_id, stream_ix, substream, av_ix, max_cnt;
  u16 pes_len, pes_left;
  mpeg2ps_ts_t ts;
  s64 loc, first_video_loc = 0, first_audio_loc = 0;
  s64 check, orig_check;
  mpeg2ps_stream_t *sptr;
  Bool valid_stream;
  u8 *buffer;
  u32 buflen;
  Bool have_ts;

  ps->end_loc = file_size(ps->fd);
  orig_check = check = MAX(ps->end_loc / 50, 200 * 1024);

  /*
   * This part reads and finds the streams.  We check up until we
   * find audio and video plus a little, with a max of either 200K or
   * the file size / 50
   */
  loc = 0;
  while (read_to_next_pes_header(ps->fd, &stream_id, &pes_len) && 
	 loc < check) {
    pes_left = pes_len;
    if (stream_id >= 0xbd && stream_id < 0xf0) {
      loc = file_location(ps->fd) - 6;
      if (read_pes_header_data(ps->fd, 
			       pes_len, 
			       &pes_left, 
			       &have_ts, 
			       &ts) == 0) {
	return;
      }
      valid_stream = 0;
      substream = 0;
      if (stream_id == 0xbd) {
	if (file_read_bytes(ps->fd, &substream, 1) == 0) {
	  return;
	}
	pes_left--; // remove byte we just read
	if ((substream >= 0x80 && substream < 0x90) ||
	    (substream >= 0xa0 && substream < 0xb0)){
	  valid_stream = 1;
	}
      } else if (stream_id >= 0xc0 &&
		 stream_id <= 0xef) {
	// audio and video
	valid_stream = 1;
      }
      if (valid_stream) {
	if (add_stream(ps, stream_id, substream, loc, &ts)) {
	  // added
	  if (stream_id >= 0xe0) {
	    if (ps->video_cnt == 1) {
	      first_video_loc = loc;
	    }
	  } else if (ps->audio_cnt == 1) {
	    first_audio_loc = loc;
	  }
	  if (ps->audio_cnt > 0 && ps->video_cnt > 0) {
	    s64 diff;
	    if (first_audio_loc > first_video_loc) 
	      diff = first_audio_loc - first_video_loc;
	    else 
	      diff = first_video_loc - first_audio_loc;
	    diff *= 2;
	    diff += first_video_loc;
	    if (diff < check) {
	      check = diff;
	    }
	  }
	}
      }
    }
    file_skip_bytes(ps->fd, pes_left);
  }
  if (ps->video_cnt == 0 && ps->audio_cnt == 0) {
    return;
  }
  /*
   * Now, we go to close to the end, and try to find the last 
   * dts that we can
   */
  //  fprintf(stderr, "to end "X64"\n", end - orig_check);
  file_seek_to(ps->fd, ps->end_loc - orig_check);

  while (read_to_next_pes_header(ps->fd, &stream_id, &pes_len)) {
    loc = file_location(ps->fd) - 6;
    if (stream_id == 0xbd || (stream_id >= 0xc0 && stream_id < 0xf0)) {
      if (read_pes_header_data(ps->fd, 
			       pes_len, 
			       &pes_left, 
			       &have_ts, 
			       &ts) == 0) {
	return;
      }
      if (stream_id == 0xbd) {
	if (file_read_bytes(ps->fd, &substream, 1) == 0) {
	  return;
	}
	pes_left--; // remove byte we just read
	if (!((substream >= 0x80 && substream < 0x90) ||
	      (substream >= 0xa0 && substream < 0xb0))) {
	  file_skip_bytes(ps->fd, pes_left);
	  continue;
	}
      } else {
	substream = 0;
      }
      sptr = find_stream_from_id(ps, stream_id, substream);
      if (sptr == NULL) {
	add_stream(ps, stream_id, substream, 0, NULL);
	sptr = find_stream_from_id(ps, stream_id, substream);
      }
      if (sptr != NULL && have_ts) {
	sptr->end_dts = ts.have_dts ? ts.dts : ts.pts;
	sptr->end_dts_loc = loc;
      }
#if 0
      fprintf(stderr, "loc "X64" stream %x %x", loc, stream_id, substream);
      if (ts.have_pts) fprintf(stderr, " pts "U64, ts.pts);
      if (ts.have_dts) fprintf(stderr, " dts "U64, ts.dts);
      fprintf(stderr, "\n");
#endif
      file_skip_bytes(ps->fd, pes_left);
    }
  }

  /*
   * Now, get the info for all streams, so we can use it again
   * we could do this before the above, I suppose
   */
  get_info_for_all_streams(ps);

  ps->first_dts = (u64) -1;

  /*
   * we need to find the earliest start pts - we use that to calc
   * the rest of the timing, so we're 0 based.
   */
  for (av_ix = 0; av_ix < 2; av_ix++) {
    if (av_ix == 0) max_cnt = ps->video_cnt;
    else max_cnt = ps->audio_cnt;

    for (stream_ix = 0; stream_ix < max_cnt; stream_ix++) {
      sptr = av_ix == 0 ? ps->video_streams[stream_ix] :
	ps->audio_streams[stream_ix];
      if (sptr != NULL && sptr->start_dts < ps->first_dts) {
	ps->first_dts = sptr->start_dts;
      }
    }
  }

  /*
   * Now, for each thread, we'll start at the last pts location, and
   * read the number of frames.  This will give us a max time
   */
  for (av_ix = 0; av_ix < 2; av_ix++) {
    if (av_ix == 0) max_cnt = ps->video_cnt;
    else max_cnt = ps->audio_cnt;
    for (stream_ix = 0; stream_ix < max_cnt; stream_ix++) {
      u32 frame_cnt_since_last;
	  sptr = av_ix == 0 ? ps->video_streams[stream_ix] :
	ps->audio_streams[stream_ix];
      
      // pick up here - find the final time...
      if (sptr->end_dts_loc != 0) {
	file_seek_to(ps->fd, sptr->end_dts_loc);
	sptr->m_fd = ps->fd;
	frame_cnt_since_last = 0;
	clear_stream_buffer(sptr);
	while (mpeg2ps_stream_read_frame(sptr,
					 &buffer, 
					 &buflen,
					 1)) {
	  frame_cnt_since_last++;
	}
	sptr->m_fd = FDNULL;
	clear_stream_buffer(sptr);
	ps->max_time = MAX(ps->max_time, 
			   convert_ts(sptr, 
				      TS_MSEC,
				      sptr->end_dts,
				      ps->first_dts, 
				      frame_cnt_since_last));
      }
    }
  }

  ps->max_dts = (ps->max_time * 90) + ps->first_dts;
  file_seek_to(ps->fd, 0);
}

/*************************************************************************
 * API routines
 *************************************************************************/
u64 mpeg2ps_get_max_time_msec (mpeg2ps_t *ps) 
{
  return ps->max_time;
}

u32 mpeg2ps_get_video_stream_count (mpeg2ps_t *ps)
{
  return ps->video_cnt;
}

#define NUM_ELEMENTS_IN_ARRAY(name) ((sizeof((name))) / (sizeof(*(name))))

// routine to check stream number passed.
static Bool invalid_video_streamno (mpeg2ps_t *ps, u32 streamno)
{
  if (streamno >= NUM_ELEMENTS_IN_ARRAY(ps->video_streams)) return 1;
  if (ps->video_streams[streamno] == NULL) return 1;
  return 0;
}

const char *mpeg2ps_get_video_stream_name (mpeg2ps_t *ps, u32 streamno)
{
  if (invalid_video_streamno(ps, streamno)) {
    return 0;
  }
  if (ps->video_streams[streamno]->have_mpeg2) {
    return "Mpeg-2";
  }
  return "Mpeg-1";
}

mpeg2ps_video_type_t mpeg2ps_get_video_stream_type (mpeg2ps_t *ps, 
						    u32 streamno)
{
  if (invalid_video_streamno(ps, streamno)) {
    return MPEG_VIDEO_UNKNOWN;
  }
  return ps->video_streams[streamno]->have_mpeg2 ? MPEG_VIDEO_MPEG2 : MPEG_VIDEO_MPEG1;
}

u32 mpeg2ps_get_video_stream_width (mpeg2ps_t *ps, u32 streamno)
{
  if (invalid_video_streamno(ps, streamno)) {
    return 0;
  }
  return ps->video_streams[streamno]->w;
}

u32 mpeg2ps_get_video_stream_height (mpeg2ps_t *ps, u32 streamno)
{
  if (invalid_video_streamno(ps, streamno)) {
    return 0;
  }
  return ps->video_streams[streamno]->h;
}

u32 mpeg2ps_get_video_stream_aspect_ratio (mpeg2ps_t *ps, u32 streamno)
{
  if (invalid_video_streamno(ps, streamno)) {
    return 0;
  }
  return ps->video_streams[streamno]->par;
}

Double mpeg2ps_get_video_stream_bitrate (mpeg2ps_t *ps, u32 streamno)
{
  if (invalid_video_streamno(ps, streamno)) {
    return 0;
  }
  return ps->video_streams[streamno]->bit_rate;
}

Double mpeg2ps_get_video_stream_framerate (mpeg2ps_t *ps, u32 streamno)
{
  if (invalid_video_streamno(ps, streamno)) {
    return 0;
  }
  return ps->video_streams[streamno]->frame_rate;
}

static Bool invalid_audio_streamno (mpeg2ps_t *ps, u32 streamno)
{
  if (streamno >= NUM_ELEMENTS_IN_ARRAY(ps->audio_streams)) return 1;
  if (ps->audio_streams[streamno] == NULL) return 1;
  return 0;
}

u32 mpeg2ps_get_audio_stream_count (mpeg2ps_t *ps)
{
  return ps->audio_cnt;
}

const char *mpeg2ps_get_audio_stream_name (mpeg2ps_t *ps, 
					   u32 streamno)
{
  if (invalid_audio_streamno(ps, streamno)) {
    return "none";
  }
  if (ps->audio_streams[streamno]->m_stream_id >= 0xc0) {
    switch (ps->audio_streams[streamno]->layer) {
    case 1: return "MP1";
    case 2: return "MP2";
    case 3: return "MP3";
    }
    return "unknown mpeg layer";
  }
  if (ps->audio_streams[streamno]->m_substream_id >= 0x80 &&
      ps->audio_streams[streamno]->m_substream_id < 0x90)
    return "AC3";

  return "LPCM";
}

mpeg2ps_audio_type_t mpeg2ps_get_audio_stream_type (mpeg2ps_t *ps, 
						    u32 streamno)
{
  if (invalid_audio_streamno(ps, streamno)) {
    return MPEG_AUDIO_UNKNOWN;
  }
  if (ps->audio_streams[streamno]->m_stream_id >= 0xc0) {
    return MPEG_AUDIO_MPEG;
  }
  if (ps->audio_streams[streamno]->m_substream_id >= 0x80 &&
      ps->audio_streams[streamno]->m_substream_id < 0x90)
    return MPEG_AUDIO_AC3;

  return MPEG_AUDIO_LPCM;
}

u32 mpeg2ps_get_audio_stream_sample_freq (mpeg2ps_t *ps, u32 streamno)
{
  if (invalid_audio_streamno(ps, streamno)) {
    return 0;
  }
  return ps->audio_streams[streamno]->freq;
}

u32 mpeg2ps_get_audio_stream_channels (mpeg2ps_t *ps, u32 streamno)
{
  if (invalid_audio_streamno(ps, streamno)) {
    return 0;
  }
  return ps->audio_streams[streamno]->channels;
}

u32 mpeg2ps_get_audio_stream_bitrate (mpeg2ps_t *ps, u32 streamno)
{
  if (invalid_audio_streamno(ps, streamno)) {
    return 0;
  }
  return ps->audio_streams[streamno]->bitrate;
}

mpeg2ps_t *mpeg2ps_init (const char *filename)
{
  mpeg2ps_t *ps;
  GF_SAFEALLOC(ps, mpeg2ps_t);

  if (ps == NULL) {
    return NULL;
  }
  memset(ps, 0, sizeof(*ps));
  ps->fd = file_open(filename);
  if (file_okay(ps->fd) == 0) {
    gf_free(ps);
    return NULL;
  }
  
  ps->filename = gf_strdup(filename);
  mpeg2ps_scan_file(ps);
  if (ps->video_cnt == 0 && ps->audio_cnt == 0) {
    mpeg2ps_close(ps);
    return NULL;
  }
  return ps;
}

void mpeg2ps_close (mpeg2ps_t *ps)
{
  u32 ix;
  if (ps == NULL) return;
  for (ix = 0; ix < ps->video_cnt; ix++) {
    mpeg2ps_stream_destroy(ps->video_streams[ix]);
    ps->video_streams[ix] = NULL;
  }
  for (ix = 0; ix < ps->audio_cnt; ix++) {
    mpeg2ps_stream_destroy(ps->audio_streams[ix]);
    ps->audio_streams[ix] = NULL;
  }

  if (ps->filename) gf_free(ps->filename);
  if (ps->fd) file_close(ps->fd);
  gf_free(ps);
}

/*
 * check_fd_for_stream will make sure we have a fd for the stream we're
 * trying to read - we use a different fd for each stream
 */

/*
 * stream_convert_frame_ts_to_msec - given a "read" frame, we'll
 * calculate the msec and freq timestamps.  This can be called more
 * than 1 time, if needed, without changing any variables, such as
 * frames_since_last_ts, which gets updated in advance_frame
 */
static u64 stream_convert_frame_ts_to_msec (mpeg2ps_stream_t *sptr, 
						 mpeg2ps_ts_type_t ts_type,
						 u64 base_dts,
						 u32 *freq_ts)
{
  u64 calc_ts;
  u32 frames_since_last = 0;
  u64 freq_conv;

  calc_ts = sptr->last_ts;
  if (sptr->frame_ts.have_dts) calc_ts = sptr->frame_ts.dts;
  else if (sptr->frame_ts.have_pts) calc_ts = sptr->frame_ts.dts;
  else frames_since_last = sptr->frames_since_last_ts + 1;

  if (freq_ts != NULL) {
    freq_conv = calc_ts - base_dts;
    freq_conv *= sptr->freq;
    freq_conv /= 90000;
    freq_conv += frames_since_last * sptr->samples_per_frame;
    *freq_ts = (u32) (freq_conv & 0xffffffff);
  }
  return convert_ts(sptr, ts_type, calc_ts, base_dts, frames_since_last);
}

/*
 * mpeg2ps_get_video_frame - gets the next frame
 */    
Bool mpeg2ps_get_video_frame(mpeg2ps_t *ps, u32 streamno,
			     u8 **buffer, 
			     u32 *buflen,
			     u8 *frame_type,
			     mpeg2ps_ts_type_t ts_type,
			     u64 *timestamp)
{
  mpeg2ps_stream_t *sptr;
  if (invalid_video_streamno(ps, streamno)) return 0;

  sptr = ps->video_streams[streamno];
  check_fd_for_stream(ps, sptr);

  if (sptr->have_frame_loaded == 0) {
    // if we don't have the frame in the buffer (like after a seek), 
    // read the next frame
    if (mpeg2ps_stream_find_mpeg_video_frame(sptr) == 0) {
      return 0;
    }
  }
  *buffer = sptr->pes_buffer + sptr->pes_buffer_on;
  *buflen = sptr->frame_len;
  // determine frame type
  if (frame_type != NULL) {
    *frame_type = MPEG12_PictHdrType(sptr->pes_buffer + 
					 sptr->pict_header_offset);
  }

  // and the timestamp
  if (timestamp != NULL) {
    *timestamp = stream_convert_frame_ts_to_msec(sptr, ts_type, 
						 ps->first_dts, NULL);
  }

  // finally, indicate that we read this frame - get ready for the next one.
  advance_frame(sptr);

  return 1;
}


// see above comments      
Bool mpeg2ps_get_audio_frame(mpeg2ps_t *ps, u32 streamno,
			     u8 **buffer, 
			     u32 *buflen,
			     mpeg2ps_ts_type_t ts_type,
			     u32 *freq_timestamp,
			     u64 *timestamp)
{
  mpeg2ps_stream_t *sptr;
  u64 ts;
  if (invalid_audio_streamno(ps, streamno)) return 0;

  sptr = ps->audio_streams[streamno];
  check_fd_for_stream(ps, sptr);

  if (sptr->have_frame_loaded == 0) {
    if (mpeg2ps_stream_read_frame(sptr, buffer, buflen, 0) == 0) 
      return 0;
  } 
  
  if (timestamp != NULL || freq_timestamp != NULL) {
    ts = stream_convert_frame_ts_to_msec(sptr, 
					 ts_type,
					 ps->first_dts,
					 freq_timestamp);
    if (timestamp != NULL) {
      *timestamp = ts;
    }
  }

  advance_frame(sptr);
  return 1;
}

u64 mpeg2ps_get_ps_size(mpeg2ps_t *ps)
{
	return file_size(ps->fd);
}
s64 mpeg2ps_get_video_pos(mpeg2ps_t *ps, u32 streamno)
{
  if (invalid_video_streamno(ps, streamno)) return 0;
  return gf_f64_tell(ps->video_streams[streamno]->m_fd);
}
s64 mpeg2ps_get_audio_pos(mpeg2ps_t *ps, u32 streamno)
{
  if (invalid_audio_streamno(ps, streamno)) return 0;
  return gf_f64_tell(ps->audio_streams[streamno]->m_fd);
}

#endif /*GPAC_DISABLE_MPEG2PS*/
