stillsstream.cpp

来自「Motion JPEG编解码器源代码」· C++ 代码 · 共 217 行

/*
 *  stillsstreams.c: Class for elemenary still video streams
 *                   Most functionality is inherited from VideoStream
 *
 *  Copyright (C) 2001 Andrew Stevens <[e-mail]>
 *
 *
 *  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.
 */


#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <format_codes.h>

#include "stillsstream.hpp"
#include "interact.hpp"
#include "multiplexor.hpp"

void StillsStream::Init ( )
{
	int stream_id = -1;
	int buffer_size = -1;

	SetBufSize( 4*1024*1024 );
	ScanFirstSeqHeader();

	mjpeg_debug( "Stills: Video buffer suggestion ignored!" );
	switch( muxinto.mux_format )
	{
	case  MPEG_FORMAT_VCD_STILL :
		if( horizontal_size > 352 )
		{
			stream_id = VIDEO_STR_0+2 ;
			buffer_size = vbv_buffer_size*2048;
			mjpeg_info( "Stills Stream %02x: high-resolution VCD stills %d KB each", 
						stream_id,
						buffer_size );
			if( buffer_size < 46*1024 )
				mjpeg_error_exit1( "I Can't multiplex high-res stills smaller than normal res stills - sorry!");

		}
		else
		{
			stream_id = VIDEO_STR_0+1 ;
			buffer_size = 46*1024;
			mjpeg_info( "Stills Stream %02x: normal VCD stills", stream_id );
		}
		break;
	case MPEG_FORMAT_SVCD_STILL :
		if( horizontal_size > 480 )
		{
			stream_id = VIDEO_STR_0+1;
			buffer_size = 230*1024;
			mjpeg_info( "Stills Stream %02x: high-resolution SVCD stills.", 
						stream_id );
		}
		else
		{
			stream_id = VIDEO_STR_0+1 ;
			buffer_size = 230*1024;
			mjpeg_info( "Stills Stream %02x: normal-resolution SVCD stills.", stream_id );
		}
		break;
	default:
		mjpeg_error_exit1( "Only SVCD and VCD Still currently supported");
	}


	MuxStream::Init( stream_id,
					 1,  // Buffer scale
					 buffer_size,
					 0,  // Zero stuffing
					 muxinto.buffers_in_video,
					 muxinto.always_buffers_in_video);
	
	/* Skip to the end of the 1st AU (*2nd* Picture start!)
	*/
	AU_hdr = SEQUENCE_HEADER;
	AU_pict_data = 0;
	AU_start = 0;

    OutputSeqhdrInfo();

}




/*
 * Compute DTS / PTS for a VCD/SVCD Stills sequence
 * TODO: Very crude. Simply assumes each still stays for the specified
 * frame interval and that enough run-in delay is present for the first
 * frame to be loaded.
 *
 */

void StillsStream::NextDTSPTS( )
{
    StillsParams *sparms = static_cast<StillsParams*>(parms);

	clockticks interval = static_cast<clockticks>
		(sparms->Intervals()->NextFrameInterval() * CLOCKS / frame_rate);
	clockticks time_for_xfer;
	muxinto.ByteposTimecode( BufferSize(), time_for_xfer );
		
	access_unit.DTS = current_PTS + time_for_xfer;	// This frame decoded just after
	                                    // Predecessor completed.
	access_unit.PTS = current_PTS + time_for_xfer + interval;
	current_PTS = access_unit.PTS;
	current_DTS = access_unit.DTS;
    fields_presented += 2;
}

/*
 * VCD mixed stills segment items have the constraint that both stills
 * streams must end together.  To do this each stream has to know
 * about its "sibling".
 *
 */

void VCDStillsStream::SetSibling( VCDStillsStream *_sibling )
{
	assert( _sibling != 0 );
	sibling = _sibling;
	if( sibling->stream_id == stream_id )
	{
		mjpeg_error_exit1("VCD mixed stills stream cannot contain two streams of the same type!");
	}

}

/*
 * Check if we've reached the last sector of the last AU.  Note: that
 * we know no PTS/DTS time-stamps will be needed because no new AU
 * will appear in the last sector.  WARNING: We assume a still won't
 * fit into a single secotr.
 *
 */

bool VCDStillsStream::LastSectorLastAU()
{
	return ( Lookahead() == 0 &&
			 au_unsent <= muxinto.PacketPayload( *this,
												 buffers_in_header, 
												 false, false )
		);
}


/*
 * The requirement that VCD mixed stills segment items constituent streams
 * end together means we can't mux the last sector of the last AU of
 * such streams until its sibling has already completed muxing or is
 * also ready to mux the last sector of its last AU.
 *
 * NOTE: Will not work right if sector_align_iframe_AUs not set as this
 * will allow multiple AU's in  a sector.
 *
 */


bool VCDStillsStream::MuxPossible(clockticks currentSCR)
{
    if( bufmodel.Size() < au_unsent )
    {
        mjpeg_error_exit1( "Illegal VCD still: larger than maximum permitted by its buffering parameters!");
    }
	if (RunOutComplete() ||	bufmodel.Space() < au_unsent)
	{
		return false;
	}
	
	if( LastSectorLastAU() )
	{
		if( sibling != 0 )
        {
            if( !stream_mismatch_warned && sibling->NextAUType() != NOFRAME  )
            {
                mjpeg_warn( "One VCD stills stream runs significantly longer than the other!");
                mjpeg_warn( "Simultaneous stream ending recommended by standard not possible" );
                return true;
            }
            return sibling->MuxCompleted() || sibling->LastSectorLastAU();
        }
        else
            return true;
	}
	else
		return true;
}



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