gstreamer/gst-libs/ext/mplex/inputstrm.cc

/*
 *  inputstrm.c:  Base classes related to muxing out input streams into
 *                the output stream.
 *
 *  Copyright (C) 2001 Andrew Stevens <andrew.stevens@philips.com>
 *
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of version 2 of the GNU General Public License
 *  as published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */


#include <config.h>
#include <assert.h>
#include "fastintfns.h"
#include "inputstrm.hh"
#include "outputstream.hh"

MuxStream::MuxStream ():init (false)
{
}


void
MuxStream::Init (const int strm_id,
		 const unsigned int _buf_scale,
		 const unsigned int buf_size,
		 const unsigned int _zero_stuffing, bool bufs_in_first, bool always_bufs)
{
  stream_id = strm_id;
  nsec = 0;
  zero_stuffing = _zero_stuffing;
  buffer_scale = _buf_scale;
  buffer_size = buf_size;
  bufmodel.Init (buf_size);
  buffers_in_header = bufs_in_first;
  always_buffers_in_header = always_bufs;
  new_au_next_sec = true;
  init = true;
}



unsigned int
MuxStream::BufferSizeCode ()
{
  if (buffer_scale == 1)
    return buffer_size / 1024;
  else if (buffer_scale == 0)
    return buffer_size / 128;
  else
    assert (false);
  return 0;
}



ElementaryStream::ElementaryStream (IBitStream & ibs, OutputStream & into, stream_kind _kind):
InputStream (ibs), muxinto (into), kind (_kind), buffer_min (INT_MAX), buffer_max (1)
{
}


bool ElementaryStream::NextAU ()
{
  Aunit *
    p_au =
    next ();

  if (p_au != NULL) {
    au = p_au;
    au_unsent = p_au->length;
    return true;
  } else {
    au_unsent = 0;
    return false;
  }
}


Aunit *
ElementaryStream::Lookahead ()
{
  return aunits.lookahead ();
}

unsigned int
ElementaryStream::BytesToMuxAUEnd (unsigned int sector_transport_size)
{
  return (au_unsent / min_packet_data) * sector_transport_size +
    (au_unsent % min_packet_data) + (sector_transport_size - min_packet_data);
}


/******************************************************************
 *	ElementaryStream::ReadPacketPayload
 *
 *  Reads the stream data from actual input stream, updates decode
 *  buffer model and current access unit information from the
 *  look-ahead scanning buffer to account for bytes_muxed bytes being
 *  muxed out.  Particular important is the maintenance of "au_unsent"
 *  the count of how much data in the current AU remains umuxed.  It
 *  not only allows us to keep track of AU's but is also used for
 *  generating substream headers
 *
 *  Unless we need to over-ride it to handle sub-stream headers
 * The packet payload for an elementary stream is simply the parsed and
 * spliced buffered stream data..
 *
 ******************************************************************/



unsigned int
ElementaryStream::ReadPacketPayload (uint8_t * dst, unsigned int to_read)
{
  unsigned int actually_read = bs.read_buffered_bytes (dst, to_read);

  Muxed (actually_read);
  return actually_read;
}




void
ElementaryStream::Muxed (unsigned int bytes_muxed)
{
  clockticks decode_time;

  if (bytes_muxed == 0 || MuxCompleted ())
    return;


  /* Work through what's left of the current AU and the following AU's
     updating the info until we reach a point where an AU had to be
     split between packets.
     NOTE: It *is* possible for this loop to iterate. 

     The DTS/PTS field for the packet in this case would have been
     given the that for the first AU to start in the packet.
     Whether Joe-Blow's hardware VCD player handles this properly is
     another matter of course!
   */

  decode_time = RequiredDTS ();
  while (au_unsent < bytes_muxed) {

    bufmodel.Queued (au_unsent, decode_time);
    bytes_muxed -= au_unsent;
    if (!NextAU ())
      return;
    new_au_next_sec = true;
    decode_time = RequiredDTS ();
  };

  // We've now reached a point where the current AU overran or
  // fitted exactly.  We need to distinguish the latter case
  // so we can record whether the next packet starts with an
  // existing AU or not - info we need to decide what PTS/DTS
  // info to write at the start of the next packet.

  if (au_unsent > bytes_muxed) {

    bufmodel.Queued (bytes_muxed, decode_time);
    au_unsent -= bytes_muxed;
    new_au_next_sec = false;
  } else			//  if (au_unsent == bytes_muxed)
  {
    bufmodel.Queued (bytes_muxed, decode_time);
    if (!NextAU ())
      return;
    new_au_next_sec = true;
  }

}

bool
ElementaryStream::MuxPossible (clockticks currentSCR)
{
  return (!RunOutComplete () && bufmodel.Space () > max_packet_data);
}


void
ElementaryStream::UpdateBufferMinMax ()
{
  buffer_min = buffer_min < (int) bufmodel.Space ()? buffer_min : bufmodel.Space ();
  buffer_max = buffer_max > (int) bufmodel.Space ()? buffer_max : bufmodel.Space ();
}



void
ElementaryStream::AllDemuxed ()
{
  bufmodel.Flushed ();
}

void
ElementaryStream::DemuxedTo (clockticks SCR)
{
  bufmodel.Cleaned (SCR);
}

bool
ElementaryStream::MuxCompleted ()
{
  return au_unsent == 0;
}

void
ElementaryStream::SetSyncOffset (clockticks sync_offset)
{
  timestamp_delay = sync_offset;
}

Aunit *
ElementaryStream::next ()
{
  Aunit *res;

  while (AUBufferNeedsRefill ()) {
    FillAUbuffer (FRAME_CHUNK);
  }
  res = aunits.next ();
  return res;
}




/* 
 * Local variables:
 *  c-file-style: "stroustrup"
 *  tab-width: 4
 *  indent-tabs-mode: nil
 * End:
 */