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371 lines
12 KiB
371 lines
12 KiB
/*****************************************************************************
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* a52.c: A/52 basic parser
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*****************************************************************************
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* Copyright (C) 2001-2002 VideoLAN
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* $Id: a52.c,v 1.22 2003/03/31 22:39:27 massiot Exp $
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*
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* Authors: Stéphane Borel <stef@via.ecp.fr>
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* Christophe Massiot <massiot@via.ecp.fr>
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* Michel Lespinasse <walken@zoy.org>
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* Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
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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 <stdio.h>
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#include <stdlib.h>
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#include <string.h> /* memcpy() */
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#include <fcntl.h>
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#include <vlc/vlc.h>
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#include <vlc/decoder.h>
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#include <vlc/aout.h>
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#ifdef HAVE_UNISTD_H
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# include <unistd.h>
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#endif
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/*****************************************************************************
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* dec_thread_t : decoder thread descriptor
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*****************************************************************************/
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typedef struct dec_thread_t
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{
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/*
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* Thread properties
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*/
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vlc_thread_t thread_id; /* id for thread functions */
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/*
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* Input properties
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*/
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decoder_fifo_t * p_fifo; /* stores the PES stream data */
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bit_stream_t bit_stream;
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/*
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* Output properties
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*/
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aout_instance_t * p_aout; /* opaque */
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aout_input_t * p_aout_input; /* opaque */
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audio_sample_format_t output_format;
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} dec_thread_t;
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/****************************************************************************
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* Local prototypes
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****************************************************************************/
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static int OpenDecoder ( vlc_object_t * );
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static int RunDecoder ( decoder_fifo_t * );
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static void EndThread ( dec_thread_t * );
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static int SyncInfo ( const byte_t *, int *, int *, int * );
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/*****************************************************************************
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* Module descriptor
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*****************************************************************************/
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vlc_module_begin();
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set_description( _("A/52 parser") );
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set_capability( "decoder", 100 );
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set_callbacks( OpenDecoder, NULL );
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vlc_module_end();
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/*****************************************************************************
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* OpenDecoder: probe the decoder and return score
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*****************************************************************************/
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static int OpenDecoder( vlc_object_t *p_this )
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{
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decoder_fifo_t *p_fifo = (decoder_fifo_t*) p_this;
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if( p_fifo->i_fourcc != VLC_FOURCC('a','5','2',' ')
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&& p_fifo->i_fourcc != VLC_FOURCC('a','5','2','b') )
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{
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return VLC_EGENERIC;
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}
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p_fifo->pf_run = RunDecoder;
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return VLC_SUCCESS;
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}
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/****************************************************************************
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* RunDecoder: the whole thing
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****************************************************************************
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* This function is called just after the thread is launched.
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****************************************************************************/
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static int RunDecoder( decoder_fifo_t *p_fifo )
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{
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dec_thread_t * p_dec;
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audio_date_t end_date;
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/* Allocate the memory needed to store the thread's structure */
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p_dec = malloc( sizeof(dec_thread_t) );
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if( p_dec == NULL )
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{
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msg_Err( p_fifo, "out of memory" );
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DecoderError( p_fifo );
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return -1;
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}
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/* Initialize the thread properties */
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p_dec->p_aout = NULL;
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p_dec->p_aout_input = NULL;
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p_dec->p_fifo = p_fifo;
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p_dec->output_format.i_format = VLC_FOURCC('a','5','2',' ');
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aout_DateSet( &end_date, 0 );
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/* Init the bitstream */
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if( InitBitstream( &p_dec->bit_stream, p_dec->p_fifo,
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NULL, NULL ) != VLC_SUCCESS )
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{
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msg_Err( p_fifo, "cannot initialize bitstream" );
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DecoderError( p_fifo );
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free( p_dec );
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return -1;
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}
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/* Decoder thread's main loop */
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while ( !p_dec->p_fifo->b_die && !p_dec->p_fifo->b_error )
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{
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int i_bit_rate;
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unsigned int i_rate, i_original_channels, i_frame_size;
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mtime_t pts;
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byte_t p_header[7];
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aout_buffer_t * p_buffer;
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/* Look for sync word - should be 0x0b77 */
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RealignBits( &p_dec->bit_stream );
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while ( (ShowBits( &p_dec->bit_stream, 16 ) ) != 0x0b77 &&
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(!p_dec->p_fifo->b_die) && (!p_dec->p_fifo->b_error) )
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{
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RemoveBits( &p_dec->bit_stream, 8 );
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}
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if ( p_dec->p_fifo->b_die || p_dec->p_fifo->b_error ) break;
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/* Set the Presentation Time Stamp */
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NextPTS( &p_dec->bit_stream, &pts, NULL );
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if ( pts != 0 && pts != aout_DateGet( &end_date ) )
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{
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aout_DateSet( &end_date, pts );
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}
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/* Get A/52 frame header */
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GetChunk( &p_dec->bit_stream, p_header, 7 );
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if ( p_dec->p_fifo->b_die || p_dec->p_fifo->b_error ) break;
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/* Check if frame is valid and get frame info */
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i_frame_size = SyncInfo( p_header, &i_original_channels, &i_rate,
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&i_bit_rate );
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if( !i_frame_size )
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{
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msg_Warn( p_dec->p_fifo, "a52_syncinfo failed" );
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continue;
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}
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if( (p_dec->p_aout_input != NULL) &&
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( (p_dec->output_format.i_rate != i_rate)
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|| (p_dec->output_format.i_original_channels
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!= i_original_channels)
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|| (p_dec->output_format.i_bytes_per_frame != i_frame_size) ) )
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{
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/* Parameters changed - this should not happen. */
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aout_DecDelete( p_dec->p_aout, p_dec->p_aout_input );
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p_dec->p_aout_input = NULL;
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}
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/* Creating the audio input if not created yet. */
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if( p_dec->p_aout_input == NULL )
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{
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p_dec->output_format.i_rate = i_rate;
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p_dec->output_format.i_original_channels = i_original_channels;
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p_dec->output_format.i_physical_channels
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= i_original_channels & AOUT_CHAN_PHYSMASK;
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p_dec->output_format.i_bytes_per_frame = i_frame_size;
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p_dec->output_format.i_frame_length = A52_FRAME_NB;
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aout_DateInit( &end_date, i_rate );
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aout_DateSet( &end_date, pts );
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p_dec->p_aout_input = aout_DecNew( p_dec->p_fifo,
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&p_dec->p_aout,
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&p_dec->output_format );
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if ( p_dec->p_aout_input == NULL )
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{
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p_dec->p_fifo->b_error = 1;
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break;
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}
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}
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if ( !aout_DateGet( &end_date ) )
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{
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byte_t p_junk[3840];
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/* We've just started the stream, wait for the first PTS. */
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GetChunk( &p_dec->bit_stream, p_junk, i_frame_size - 7 );
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continue;
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}
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p_buffer = aout_DecNewBuffer( p_dec->p_aout, p_dec->p_aout_input,
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A52_FRAME_NB );
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if ( p_buffer == NULL )
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{
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p_dec->p_fifo->b_error = 1;
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break;
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}
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p_buffer->start_date = aout_DateGet( &end_date );
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p_buffer->end_date = aout_DateIncrement( &end_date,
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A52_FRAME_NB );
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/* Get the whole frame. */
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memcpy( p_buffer->p_buffer, p_header, 7 );
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GetChunk( &p_dec->bit_stream, p_buffer->p_buffer + 7,
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i_frame_size - 7 );
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if( p_dec->p_fifo->b_die )
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{
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aout_DecDeleteBuffer( p_dec->p_aout, p_dec->p_aout_input,
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p_buffer );
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break;
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}
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/* Send the buffer to the aout core. */
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aout_DecPlay( p_dec->p_aout, p_dec->p_aout_input, p_buffer );
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}
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if( p_dec->p_fifo->b_error )
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{
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DecoderError( p_dec->p_fifo );
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}
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EndThread( p_dec );
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return 0;
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}
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/*****************************************************************************
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* EndThread : thread destruction
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*****************************************************************************/
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static void EndThread( dec_thread_t * p_dec )
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{
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if ( p_dec->p_aout_input != NULL )
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{
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aout_DecDelete( p_dec->p_aout, p_dec->p_aout_input );
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}
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CloseBitstream( &p_dec->bit_stream );
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free( p_dec );
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}
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/*****************************************************************************
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* SyncInfo: parse A/52 sync info
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*****************************************************************************
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* This code is borrowed from liba52 by Aaron Holtzman & Michel Lespinasse,
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* since we don't want to oblige S/PDIF people to use liba52 just to get
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* their SyncInfo...
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*****************************************************************************/
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static int SyncInfo( const byte_t * p_buf, int * pi_channels,
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int * pi_sample_rate, int * pi_bit_rate )
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{
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static const uint8_t halfrate[12] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3 };
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static const int rate[] = { 32, 40, 48, 56, 64, 80, 96, 112,
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128, 160, 192, 224, 256, 320, 384, 448,
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512, 576, 640 };
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static const uint8_t lfeon[8] = { 0x10, 0x10, 0x04, 0x04,
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0x04, 0x01, 0x04, 0x01 };
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int frmsizecod;
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int bitrate;
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int half;
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int acmod;
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if ((p_buf[0] != 0x0b) || (p_buf[1] != 0x77)) /* syncword */
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return 0;
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if (p_buf[5] >= 0x60) /* bsid >= 12 */
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return 0;
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half = halfrate[p_buf[5] >> 3];
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/* acmod, dsurmod and lfeon */
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acmod = p_buf[6] >> 5;
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if ( (p_buf[6] & 0xf8) == 0x50 )
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{
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/* Dolby surround = stereo + Dolby */
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*pi_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
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| AOUT_CHAN_DOLBYSTEREO;
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}
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else switch ( acmod )
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{
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case 0x0:
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/* Dual-mono = stereo + dual-mono */
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*pi_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
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| AOUT_CHAN_DUALMONO;
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break;
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case 0x1:
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/* Mono */
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*pi_channels = AOUT_CHAN_CENTER;
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break;
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case 0x2:
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/* Stereo */
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*pi_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
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break;
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case 0x3:
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/* 3F */
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*pi_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER;
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break;
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case 0x4:
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/* 2F1R */
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*pi_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_REARCENTER;
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break;
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case 0x5:
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/* 3F1R */
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*pi_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
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| AOUT_CHAN_REARCENTER;
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break;
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case 0x6:
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/* 2F2R */
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*pi_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
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| AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT;
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break;
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case 0x7:
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/* 3F2R */
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*pi_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
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| AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT;
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break;
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default:
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return 0;
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}
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if ( p_buf[6] & lfeon[acmod] ) *pi_channels |= AOUT_CHAN_LFE;
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frmsizecod = p_buf[4] & 63;
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if (frmsizecod >= 38)
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return 0;
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bitrate = rate [frmsizecod >> 1];
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*pi_bit_rate = (bitrate * 1000) >> half;
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switch (p_buf[4] & 0xc0) {
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case 0:
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*pi_sample_rate = 48000 >> half;
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return 4 * bitrate;
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case 0x40:
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*pi_sample_rate = 44100 >> half;
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return 2 * (320 * bitrate / 147 + (frmsizecod & 1));
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case 0x80:
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*pi_sample_rate = 32000 >> half;
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return 6 * bitrate;
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default:
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return 0;
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}
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}
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