mirror of https://code.videolan.org/videolan/vlc
158 lines
6.3 KiB
C
158 lines
6.3 KiB
C
/*****************************************************************************
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* input_ext-dec.c: services to the decoders
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*****************************************************************************
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* Copyright (C) 1998, 1999, 2000 VideoLAN
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*
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* Authors:
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
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*****************************************************************************/
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/*****************************************************************************
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* Preamble
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*****************************************************************************/
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#include "defs.h"
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#include "config.h"
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#include "common.h"
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#include "threads.h"
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#include "mtime.h"
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#include "intf_msg.h"
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#include "stream_control.h"
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#include "input_ext-dec.h"
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#include "input.h"
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/*****************************************************************************
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* InitBitstream: initialize a bit_stream_t structure
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*****************************************************************************/
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void InitBitstream( bit_stream_t * p_bit_stream, decoder_fifo_t * p_fifo )
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{
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p_bit_stream->p_decoder_fifo = p_fifo;
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p_bit_stream->pf_next_data_packet = NextDataPacket;
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/* Get the first data packet. */
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vlc_mutex_lock( &p_fifo->data_lock );
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while ( DECODER_FIFO_ISEMPTY( *p_fifo ) )
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{
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if ( p_fifo->b_die )
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{
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vlc_mutex_unlock( &p_fifo->data_lock );
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return;
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}
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vlc_cond_wait( &p_fifo->data_wait, &p_fifo->data_lock );
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}
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p_bit_stream->p_data = DECODER_FIFO_START( *p_fifo )->p_first;
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p_bit_stream->p_byte = p_bit_stream->p_data->p_payload_start;
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p_bit_stream->p_end = p_bit_stream->p_data->p_payload_end;
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p_bit_stream->fifo.buffer = 0;
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p_bit_stream->fifo.i_available = 0;
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vlc_mutex_unlock( &p_fifo->data_lock );
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}
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/*****************************************************************************
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* NextDataPacket: go to the next data packet
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*****************************************************************************/
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void NextDataPacket( bit_stream_t * p_bit_stream )
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{
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WORD_TYPE buffer_left;
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/* FIXME : not portable in a 64bit environment */
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int i_bytes_left;
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decoder_fifo_t * p_fifo = p_bit_stream->p_decoder_fifo;
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/* Buffer used at the end of a decoder thread, to give it zero
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* values if needed. */
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static byte_t p_zero[64] = { 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0 };
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/* Put the remaining bytes (not aligned on a word boundary) in a
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* temporary buffer. */
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i_bytes_left = p_bit_stream->p_end - p_bit_stream->p_byte;
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buffer_left = *((WORD_TYPE *)p_bit_stream->p_end - 1);
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/* We are looking for the next data packet that contains real data,
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* and not just a PES header */
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do
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{
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/* We were reading the last data packet of this PES packet... It's
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* time to jump to the next PES packet */
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if( p_bit_stream->p_data->p_next == NULL )
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{
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/* We are going to read/write the start and end indexes of the
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* decoder fifo and to use the fifo's conditional variable,
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* that's why we need to take the lock before. */
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vlc_mutex_lock( &p_fifo->data_lock );
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/* Is the input thread dying ? */
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if( p_fifo->b_die )
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{
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vlc_mutex_unlock( &p_fifo->data_lock );
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p_bit_stream->p_byte = p_zero;
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p_bit_stream->p_end = &p_zero[sizeof(p_zero) - 1];
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return;
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}
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/* We should increase the start index of the decoder fifo, but
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* if we do this now, the input thread could overwrite the
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* pointer to the current PES packet, and we weren't able to
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* give it back to the netlist. That's why we free the PES
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* packet first. */
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p_fifo->pf_delete_pes( p_fifo->p_packets_mgt,
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DECODER_FIFO_START( *p_fifo ) );
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DECODER_FIFO_INCSTART( *p_fifo );
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while( DECODER_FIFO_ISEMPTY( *p_fifo ) )
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{
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vlc_cond_wait( &p_fifo->data_wait, &p_fifo->data_lock );
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if( p_fifo->b_die )
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{
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vlc_mutex_unlock( &p_fifo->data_lock );
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p_bit_stream->p_byte = p_zero;
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p_bit_stream->p_end = &p_zero[sizeof(p_zero) - 1];
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return;
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}
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}
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/* The next byte could be found in the next PES packet */
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p_bit_stream->p_data = DECODER_FIFO_START( *p_fifo )->p_first;
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/* We can release the fifo's data lock */
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vlc_mutex_unlock( &p_fifo->data_lock );
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}
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else
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{
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/* Perhaps the next data packet of the current PES packet contains
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* real data (ie its payload's size is greater than 0). */
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p_bit_stream->p_data = p_bit_stream->p_data->p_next;
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}
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} while ( p_bit_stream->p_data->p_payload_start
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== p_bit_stream->p_data->p_payload_end );
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/* We've found a data packet which contains interesting data... */
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p_bit_stream->p_byte = p_bit_stream->p_data->p_payload_start;
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p_bit_stream->p_end = p_bit_stream->p_data->p_payload_end;
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/* Copy remaining bits of the previous packet */
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*((WORD_TYPE *)p_bit_stream->p_byte - 1) = buffer_left;
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p_bit_stream->p_byte -= i_bytes_left;
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}
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