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322 lines
10 KiB
322 lines
10 KiB
/*****************************************************************************
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* lpcm.c: lpcm decoder module
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*****************************************************************************
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* Copyright (C) 1999-2001 VideoLAN
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* $Id: lpcm.c,v 1.10 2003/01/02 20:48:28 gbazin Exp $
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*
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* Authors: Samuel Hocevar <sam@zoy.org>
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* Henri Fallon <henri@videolan.org>
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* Christophe Massiot <massiot@via.ecp.fr>
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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 <stdlib.h> /* malloc(), free() */
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#include <string.h> /* memcpy(), memset() */
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#include <vlc/vlc.h>
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#include <vlc/aout.h>
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#include <vlc/decoder.h>
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#include <input_ext-dec.h>
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#ifdef HAVE_UNISTD_H
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# include <unistd.h> /* getpid() */
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#endif
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/* DVD PES size (2048) - 40 bytes (headers) */
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#define LPCM_FRAME_LENGTH 2008
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/*****************************************************************************
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* dec_thread_t : lpcm 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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int sync_ptr; /* sync ptr from lpcm magic header */
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/*
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* Output properties
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*/
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aout_instance_t *p_aout;
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aout_input_t *p_aout_input;
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audio_sample_format_t output_format;
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audio_date_t end_date;
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} dec_thread_t;
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/*
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* LPCM header :
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* - PES header
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* - private stream ID (16 bits) == 0xA0 -> not in the bitstream
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* - frame number (8 bits)
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* - unknown (16 bits) == 0x0003 ?
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* - unknown (4 bits)
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* - current frame (4 bits)
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* - unknown (2 bits)
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* - frequency (2 bits) 0 == 48 kHz, 1 == 32 kHz, 2 == ?, 3 == ?
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* - unknown (1 bit)
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* - number of channels - 1 (3 bits) 1 == 2 channels
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* - start code (8 bits) == 0x80
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*/
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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 DecodeFrame ( dec_thread_t * );
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static void EndThread ( dec_thread_t * );
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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( _("linear PCM audio 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('l','p','c','m')
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&& p_fifo->i_fourcc != VLC_FOURCC('l','p','c','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 lpcm decoder
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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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/* Allocate the memory needed to store the thread's structure */
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if( (p_dec = (dec_thread_t *)malloc (sizeof(dec_thread_t)) )
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== 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_fifo = p_fifo;
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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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EndThread( p_dec );
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return -1;
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}
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p_dec->output_format.i_format = VLC_FOURCC('s','1','6','b');
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p_dec->p_aout = NULL;
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p_dec->p_aout_input = NULL;
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/* LPCM 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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DecodeFrame(p_dec);
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}
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/* If b_error is set, the lpcm decoder thread enters the error loop */
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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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/* End of the lpcm decoder thread */
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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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* DecodeFrame: decodes a frame.
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*****************************************************************************/
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static void DecodeFrame( dec_thread_t * p_dec )
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{
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aout_buffer_t * p_buffer;
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mtime_t i_pts;
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uint8_t i_header;
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unsigned int i_rate, i_original_channels, i_nb_channels;
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/* Look for sync word - should be 0xXX80 */
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RealignBits( &p_dec->bit_stream );
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while ( (ShowBits( &p_dec->bit_stream, 16 ) & 0xc8ff) != 0x0080 &&
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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 ) return;
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NextPTS( &p_dec->bit_stream, &i_pts, NULL );
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if( i_pts != 0 && i_pts != aout_DateGet( &p_dec->end_date ) )
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{
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aout_DateSet( &p_dec->end_date, i_pts );
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}
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/* Get LPCM header. */
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i_header = GetBits( &p_dec->bit_stream, 16 ) >> 8;
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switch ( i_header >> 4 )
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{
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case 0:
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i_rate = 48000;
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break;
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case 1:
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i_rate = 32000;
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break;
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default:
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msg_Err( p_dec->p_fifo, "unsupported LPCM rate (0x%x)", i_header );
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p_dec->p_fifo->b_error = 1;
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return;
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}
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switch ( i_header & 0x7 )
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{
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case 0:
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i_original_channels = AOUT_CHAN_CENTER;
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i_nb_channels = 1;
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break;
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case 1:
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i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
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i_nb_channels = 2;
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break;
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case 3:
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i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
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| AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT;
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i_nb_channels = 4;
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break;
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case 5:
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i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
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| AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT
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| AOUT_CHAN_CENTER | AOUT_CHAN_LFE;
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i_nb_channels = 6;
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break;
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case 2:
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case 4:
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case 6:
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case 7:
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default:
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msg_Err( p_dec->p_fifo, "unsupported LPCM channels (0x%x)",
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i_header );
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p_dec->p_fifo->b_error = 1;
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return;
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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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{
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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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aout_DateInit( &p_dec->end_date, i_rate );
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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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return;
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}
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}
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if ( !aout_DateGet( &p_dec->end_date ) )
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{
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byte_t p_junk[LPCM_FRAME_LENGTH];
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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, LPCM_FRAME_LENGTH );
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return;
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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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LPCM_FRAME_LENGTH / p_dec->output_format.i_bytes_per_frame );
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if( p_buffer == NULL )
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{
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msg_Err( p_dec->p_fifo, "cannot get aout buffer" );
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p_dec->p_fifo->b_error = 1;
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return;
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}
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p_buffer->start_date = aout_DateGet( &p_dec->end_date );
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p_buffer->end_date = aout_DateIncrement( &p_dec->end_date,
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LPCM_FRAME_LENGTH / p_dec->output_format.i_bytes_per_frame );
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/* Get the whole frame. */
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GetChunk( &p_dec->bit_stream, p_buffer->p_buffer,
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LPCM_FRAME_LENGTH);
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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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return;
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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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/*****************************************************************************
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* EndThread : lpcm decoder 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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