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399 lines
13 KiB
399 lines
13 KiB
/*****************************************************************************
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* lpcm.c: lpcm decoder/packetizer module
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*****************************************************************************
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* Copyright (C) 1999-2005 the VideoLAN team
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* $Id$
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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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* Gildas Bazin <gbazin@videolan.org>
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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., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
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*****************************************************************************/
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/*****************************************************************************
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* Preamble
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*****************************************************************************/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <vlc/vlc.h>
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#include <vlc_plugin.h>
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#include <vlc_codec.h>
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#include <vlc_aout.h>
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/*****************************************************************************
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* decoder_sys_t : lpcm decoder descriptor
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*****************************************************************************/
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struct decoder_sys_t
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{
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/* Module mode */
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bool b_packetizer;
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/*
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* Output properties
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*/
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audio_date_t end_date;
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};
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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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*
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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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#define LPCM_HEADER_LEN 6
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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 OpenPacketizer( vlc_object_t * );
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static void CloseDecoder ( vlc_object_t * );
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static void *DecodeFrame ( decoder_t *, block_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_category( CAT_INPUT );
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set_subcategory( SUBCAT_INPUT_ACODEC );
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set_description( _("Linear PCM audio decoder") );
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set_capability( "decoder", 100 );
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set_callbacks( OpenDecoder, CloseDecoder );
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add_submodule();
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set_description( _("Linear PCM audio packetizer") );
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set_capability( "packetizer", 100 );
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set_callbacks( OpenPacketizer, CloseDecoder );
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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_t *p_dec = (decoder_t*)p_this;
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decoder_sys_t *p_sys;
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if( p_dec->fmt_in.i_codec != VLC_FOURCC('l','p','c','m')
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&& p_dec->fmt_in.i_codec != 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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/* Allocate the memory needed to store the decoder's structure */
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if( ( p_dec->p_sys = p_sys =
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(decoder_sys_t *)malloc(sizeof(decoder_sys_t)) ) == NULL )
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return VLC_ENOMEM;
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/* Misc init */
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p_sys->b_packetizer = false;
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aout_DateSet( &p_sys->end_date, 0 );
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/* Set output properties */
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p_dec->fmt_out.i_cat = AUDIO_ES;
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if( p_dec->fmt_out.audio.i_bitspersample == 24 )
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{
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p_dec->fmt_out.i_codec = VLC_FOURCC('s','2','4','b');
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}
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else
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{
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p_dec->fmt_out.i_codec = VLC_FOURCC('s','1','6','b');
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p_dec->fmt_out.audio.i_bitspersample = 16;
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}
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/* Set callback */
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p_dec->pf_decode_audio = (aout_buffer_t *(*)(decoder_t *, block_t **))
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DecodeFrame;
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p_dec->pf_packetize = (block_t *(*)(decoder_t *, block_t **))
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DecodeFrame;
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return VLC_SUCCESS;
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}
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static int OpenPacketizer( vlc_object_t *p_this )
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{
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decoder_t *p_dec = (decoder_t*)p_this;
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int i_ret = OpenDecoder( p_this );
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if( i_ret != VLC_SUCCESS ) return i_ret;
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p_dec->p_sys->b_packetizer = true;
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p_dec->fmt_out.i_codec = VLC_FOURCC('l','p','c','m');
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return i_ret;
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}
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/*****************************************************************************
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* DecodeFrame: decodes an lpcm frame.
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****************************************************************************
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* Beware, this function must be fed with complete frames (PES packet).
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*****************************************************************************/
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static void *DecodeFrame( decoder_t *p_dec, block_t **pp_block )
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{
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decoder_sys_t *p_sys = p_dec->p_sys;
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block_t *p_block;
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unsigned int i_rate = 0, i_original_channels = 0, i_channels = 0;
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int i_frame_length, i_bitspersample;
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uint8_t i_header;
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if( !pp_block || !*pp_block ) return NULL;
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p_block = *pp_block;
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*pp_block = NULL; /* So the packet doesn't get re-sent */
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/* Date management */
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if( p_block->i_pts > 0 &&
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p_block->i_pts != aout_DateGet( &p_sys->end_date ) )
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{
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aout_DateSet( &p_sys->end_date, p_block->i_pts );
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}
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if( !aout_DateGet( &p_sys->end_date ) )
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{
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/* We've just started the stream, wait for the first PTS. */
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block_Release( p_block );
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return NULL;
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}
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if( p_block->i_buffer <= LPCM_HEADER_LEN )
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{
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msg_Err(p_dec, "frame is too short");
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block_Release( p_block );
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return NULL;
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}
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i_header = p_block->p_buffer[4];
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switch ( (i_header >> 4) & 0x3 )
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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 = 96000;
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break;
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case 2:
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i_rate = 44100;
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break;
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case 3:
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i_rate = 32000;
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break;
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}
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i_channels = (i_header & 0x7);
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switch ( i_channels )
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{
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case 0:
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i_original_channels = AOUT_CHAN_CENTER;
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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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break;
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case 2:
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/* This is unsure. */
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i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_LFE;
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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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break;
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case 4:
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/* This is unsure. */
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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_LFE;
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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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break;
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case 6:
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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_MIDDLELEFT
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| AOUT_CHAN_MIDDLERIGHT;
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break;
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case 7:
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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_MIDDLELEFT
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| AOUT_CHAN_MIDDLERIGHT | AOUT_CHAN_LFE;
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break;
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}
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switch ( (i_header >> 6) & 0x3 )
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{
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case 2:
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p_dec->fmt_out.i_codec = VLC_FOURCC('s','2','4','b');
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p_dec->fmt_out.audio.i_bitspersample = 24;
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i_bitspersample = 24;
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break;
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case 1:
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p_dec->fmt_out.i_codec = VLC_FOURCC('s','2','4','b');
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p_dec->fmt_out.audio.i_bitspersample = 24;
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i_bitspersample = 20;
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break;
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case 0:
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default:
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p_dec->fmt_out.i_codec = VLC_FOURCC('s','1','6','b');
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p_dec->fmt_out.audio.i_bitspersample = 16;
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i_bitspersample = 16;
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break;
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}
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/* Check frame sync and drop it. */
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if( p_block->p_buffer[5] != 0x80 )
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{
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msg_Warn( p_dec, "no frame sync" );
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block_Release( p_block );
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return NULL;
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}
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/* Set output properties */
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if( p_dec->fmt_out.audio.i_rate != i_rate )
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{
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aout_DateInit( &p_sys->end_date, i_rate );
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aout_DateSet( &p_sys->end_date, p_block->i_pts );
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}
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p_dec->fmt_out.audio.i_rate = i_rate;
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p_dec->fmt_out.audio.i_channels = i_channels + 1;
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p_dec->fmt_out.audio.i_original_channels = i_original_channels;
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p_dec->fmt_out.audio.i_physical_channels
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= i_original_channels & AOUT_CHAN_PHYSMASK;
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i_frame_length = (p_block->i_buffer - LPCM_HEADER_LEN) /
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p_dec->fmt_out.audio.i_channels * 8 / i_bitspersample;
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if( p_sys->b_packetizer )
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{
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p_dec->fmt_out.i_codec = VLC_FOURCC('l','p','c','m');
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p_block->i_pts = p_block->i_dts = aout_DateGet( &p_sys->end_date );
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p_block->i_length =
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aout_DateIncrement( &p_sys->end_date, i_frame_length ) -
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p_block->i_pts;
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/* Just pass on the incoming frame */
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return p_block;
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}
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else
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{
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aout_buffer_t *p_aout_buffer;
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p_aout_buffer = p_dec->pf_aout_buffer_new( p_dec, i_frame_length );
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if( p_aout_buffer == NULL ) return NULL;
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p_aout_buffer->start_date = aout_DateGet( &p_sys->end_date );
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p_aout_buffer->end_date =
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aout_DateIncrement( &p_sys->end_date, i_frame_length );
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p_block->p_buffer += LPCM_HEADER_LEN;
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p_block->i_buffer -= LPCM_HEADER_LEN;
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/* 20/24 bits LPCM use special packing */
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if( i_bitspersample == 24 )
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{
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uint8_t *p_out = p_aout_buffer->p_buffer;
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while( p_block->i_buffer / 12 )
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{
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/* Sample 1 */
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p_out[0] = p_block->p_buffer[0];
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p_out[1] = p_block->p_buffer[1];
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p_out[2] = p_block->p_buffer[8];
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/* Sample 2 */
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p_out[3] = p_block->p_buffer[2];
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p_out[4] = p_block->p_buffer[3];
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p_out[5] = p_block->p_buffer[9];
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/* Sample 3 */
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p_out[6] = p_block->p_buffer[4];
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p_out[7] = p_block->p_buffer[5];
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p_out[8] = p_block->p_buffer[10];
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/* Sample 4 */
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p_out[9] = p_block->p_buffer[6];
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p_out[10] = p_block->p_buffer[7];
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p_out[11] = p_block->p_buffer[11];
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p_block->i_buffer -= 12;
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p_block->p_buffer += 12;
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p_out += 12;
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}
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}
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else if( i_bitspersample == 20 )
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{
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uint8_t *p_out = p_aout_buffer->p_buffer;
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while( p_block->i_buffer / 10 )
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{
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/* Sample 1 */
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p_out[0] = p_block->p_buffer[0];
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p_out[1] = p_block->p_buffer[1];
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p_out[2] = p_block->p_buffer[8] & 0xF0;
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/* Sample 2 */
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p_out[3] = p_block->p_buffer[2];
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p_out[4] = p_block->p_buffer[3];
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p_out[5] = p_block->p_buffer[8] << 4;
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/* Sample 3 */
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p_out[6] = p_block->p_buffer[4];
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p_out[7] = p_block->p_buffer[5];
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p_out[8] = p_block->p_buffer[9] & 0xF0;
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/* Sample 4 */
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p_out[9] = p_block->p_buffer[6];
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p_out[10] = p_block->p_buffer[7];
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p_out[11] = p_block->p_buffer[9] << 4;
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p_block->i_buffer -= 10;
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p_block->p_buffer += 10;
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p_out += 12;
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}
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}
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else
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{
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memcpy( p_aout_buffer->p_buffer,
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p_block->p_buffer, p_block->i_buffer );
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}
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block_Release( p_block );
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return p_aout_buffer;
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}
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}
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/*****************************************************************************
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* CloseDecoder : lpcm decoder destruction
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*****************************************************************************/
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static void CloseDecoder( vlc_object_t *p_this )
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{
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decoder_t *p_dec = (decoder_t*)p_this;
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free( p_dec->p_sys );
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}
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