gstreamer/ext/mplex/inputstrm.cc

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/*
* 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);
}
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:
*/