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vlc/modules/codec/a52.c
Christophe Massiot 7a58ef70ff * Major API change of the audio output. New aout_Dec* functions. 
* Fixed a compile issue in s16tofloat32swab.
* Fixed a typo in demux/mpeg/ts.c.
2002-09-26 22:40:27 +00:00

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/*****************************************************************************
* a52.c: A/52 basic parser
*****************************************************************************
* Copyright (C) 2001-2002 VideoLAN
* $Id: a52.c,v 1.13 2002/09/26 22:40:20 massiot Exp $
*
* Authors: Stéphane Borel <stef@via.ecp.fr>
* Christophe Massiot <massiot@via.ecp.fr>
* Michel Lespinasse <walken@zoy.org>
* Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
*****************************************************************************/
/*****************************************************************************
* Preamble
*****************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <string.h> /* memcpy() */
#include <fcntl.h>
#include <vlc/vlc.h>
#include <vlc/decoder.h>
#include <vlc/aout.h>
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
#define A52_FRAME_NB 1536
/*****************************************************************************
* dec_thread_t : A52 pass-through thread descriptor
*****************************************************************************/
typedef struct dec_thread_t
{
/*
* Thread properties
*/
vlc_thread_t thread_id; /* id for thread functions */
/*
* Input properties
*/
decoder_fifo_t * p_fifo; /* stores the PES stream data */
bit_stream_t bit_stream;
/*
* Output properties
*/
aout_instance_t * p_aout; /* opaque */
aout_input_t * p_aout_input; /* opaque */
audio_sample_format_t output_format;
} dec_thread_t;
/****************************************************************************
* Local prototypes
****************************************************************************/
static int OpenDecoder ( vlc_object_t * );
static int RunDecoder ( decoder_fifo_t * );
static void EndThread ( dec_thread_t * );
static int SyncInfo ( const byte_t *, int *, int *, int * );
/*****************************************************************************
* Module descriptor
*****************************************************************************/
vlc_module_begin();
set_description( _("A/52 parser") );
set_capability( "decoder", 100 );
set_callbacks( OpenDecoder, NULL );
vlc_module_end();
/*****************************************************************************
* OpenDecoder: probe the decoder and return score
*****************************************************************************/
static int OpenDecoder( vlc_object_t *p_this )
{
decoder_fifo_t *p_fifo = (decoder_fifo_t*) p_this;
if( p_fifo->i_fourcc != VLC_FOURCC('a','5','2',' ')
&& p_fifo->i_fourcc != VLC_FOURCC('a','5','2','b') )
{
return VLC_EGENERIC;
}
p_fifo->pf_run = RunDecoder;
return VLC_SUCCESS;
}
/****************************************************************************
* RunDecoder: the whole thing
****************************************************************************
* This function is called just after the thread is launched.
****************************************************************************/
static int RunDecoder( decoder_fifo_t *p_fifo )
{
dec_thread_t * p_dec;
audio_date_t end_date;
/* Allocate the memory needed to store the thread's structure */
p_dec = malloc( sizeof(dec_thread_t) );
if( p_dec == NULL )
{
msg_Err( p_fifo, "out of memory" );
DecoderError( p_fifo );
return -1;
}
/* Initialize the thread properties */
p_dec->p_aout = NULL;
p_dec->p_aout_input = NULL;
p_dec->p_fifo = p_fifo;
p_dec->output_format.i_format = AOUT_FMT_A52;
/* Init the bitstream */
InitBitstream( &p_dec->bit_stream, p_dec->p_fifo,
NULL, NULL );
/* decoder thread's main loop */
while ( !p_dec->p_fifo->b_die && !p_dec->p_fifo->b_error )
{
int i_frame_size, i_channels, i_rate, i_bit_rate;
mtime_t pts;
byte_t p_header[7];
aout_buffer_t * p_buffer;
/* Look for sync word - should be 0x0b77 */
RealignBits( &p_dec->bit_stream );
while ( (ShowBits( &p_dec->bit_stream, 16 ) ) != 0x0b77 &&
(!p_dec->p_fifo->b_die) && (!p_dec->p_fifo->b_error))
{
RemoveBits( &p_dec->bit_stream, 8 );
}
/* Set the Presentation Time Stamp */
NextPTS( &p_dec->bit_stream, &pts, NULL );
if ( pts != 0 && pts != aout_DateGet( &end_date ) )
{
aout_DateSet( &end_date, pts );
}
/* Get A/52 frame header */
GetChunk( &p_dec->bit_stream, p_header, 7 );
if( p_dec->p_fifo->b_die ) break;
/* Check if frame is valid and get frame info */
i_frame_size = SyncInfo( p_header, &i_channels, &i_rate,
&i_bit_rate );
if( !i_frame_size )
{
msg_Warn( p_dec->p_fifo, "a52_syncinfo failed" );
continue;
}
if( (p_dec->p_aout_input != NULL) &&
( (p_dec->output_format.i_rate != i_rate)
|| (p_dec->output_format.i_channels != i_channels)
|| (p_dec->output_format.i_bytes_per_frame != i_frame_size) ) )
{
/* Parameters changed - this should not happen. */
aout_DecDelete( p_dec->p_aout, p_dec->p_aout_input );
p_dec->p_aout_input = NULL;
}
/* Creating the audio input if not created yet. */
if( p_dec->p_aout_input == NULL )
{
p_dec->output_format.i_rate = i_rate;
p_dec->output_format.i_channels = i_channels;
p_dec->output_format.i_bytes_per_frame = i_frame_size;
p_dec->output_format.i_frame_length = A52_FRAME_NB;
aout_DateInit( &end_date, i_rate );
p_dec->p_aout_input = aout_DecNew( p_dec->p_fifo,
&p_dec->p_aout,
&p_dec->output_format );
if ( p_dec->p_aout_input == NULL )
{
p_dec->p_fifo->b_error = 1;
break;
}
}
if ( !aout_DateGet( &end_date ) )
{
byte_t p_junk[3840];
/* We've just started the stream, wait for the first PTS. */
GetChunk( &p_dec->bit_stream, p_junk, i_frame_size - 7 );
continue;
}
p_buffer = aout_DecNewBuffer( p_dec->p_aout, p_dec->p_aout_input,
A52_FRAME_NB );
if ( p_buffer == NULL ) return -1;
p_buffer->start_date = aout_DateGet( &end_date );
p_buffer->end_date = aout_DateIncrement( &end_date,
A52_FRAME_NB );
/* Get the whole frame. */
memcpy( p_buffer->p_buffer, p_header, 7 );
GetChunk( &p_dec->bit_stream, p_buffer->p_buffer + 7,
i_frame_size - 7 );
if( p_dec->p_fifo->b_die )
{
aout_DecDeleteBuffer( p_dec->p_aout, p_dec->p_aout_input,
p_buffer );
break;
}
/* Send the buffer to the mixer. */
aout_DecPlay( p_dec->p_aout, p_dec->p_aout_input, p_buffer );
}
/* If b_error is set, the spdif thread enters the error loop */
if( p_dec->p_fifo->b_error )
{
DecoderError( p_dec->p_fifo );
}
/* End of the spdif decoder thread */
EndThread( p_dec );
return 0;
}
/*****************************************************************************
* EndThread : spdif thread destruction
*****************************************************************************/
static void EndThread( dec_thread_t * p_dec )
{
if ( p_dec->p_aout_input != NULL )
{
aout_DecDelete( p_dec->p_aout, p_dec->p_aout_input );
}
free( p_dec );
}
/****************************************************************************
* SyncInfo: parse A52 sync info
****************************************************************************
* This code is borrowed from liba52 by Aaron Holtzman & Michel Lespinasse,
* since we don't want to oblige S/PDIF people to use liba52 just to get
* their SyncInfo...
****************************************************************************/
int SyncInfo( const byte_t * p_buf, int * pi_channels, int * pi_sample_rate,
int * pi_bit_rate)
{
static const u8 halfrate[12] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3};
static const int rate[] = { 32, 40, 48, 56, 64, 80, 96, 112,
128, 160, 192, 224, 256, 320, 384, 448,
512, 576, 640};
static const u8 lfeon[8] = {0x10, 0x10, 0x04, 0x04, 0x04, 0x01, 0x04, 0x01};
int frmsizecod;
int bitrate;
int half;
int acmod;
if ((p_buf[0] != 0x0b) || (p_buf[1] != 0x77)) /* syncword */
return 0;
if (p_buf[5] >= 0x60) /* bsid >= 12 */
return 0;
half = halfrate[p_buf[5] >> 3];
/* acmod, dsurmod and lfeon */
acmod = p_buf[6] >> 5;
if ( p_buf[6] & 0xf8 )
{
*pi_channels = AOUT_CHAN_DOLBY;
}
else switch ( acmod )
{
case 0x0: *pi_channels = AOUT_CHAN_CHANNEL; break;
case 0x1: *pi_channels = AOUT_CHAN_MONO; break;
case 0x2: *pi_channels = AOUT_CHAN_STEREO; break;
case 0x3: *pi_channels = AOUT_CHAN_3F; break;
case 0x4: *pi_channels = AOUT_CHAN_2F1R; break;
case 0x5: *pi_channels = AOUT_CHAN_3F1R; break;
case 0x6: *pi_channels = AOUT_CHAN_2F2R; break;
case 0x7: *pi_channels = AOUT_CHAN_3F2R; break;
case 0x8: *pi_channels = AOUT_CHAN_CHANNEL1; break;
case 0x9: *pi_channels = AOUT_CHAN_CHANNEL2; break;
}
if ( p_buf[6] & lfeon[acmod] ) *pi_channels |= AOUT_CHAN_LFE;
frmsizecod = p_buf[4] & 63;
if (frmsizecod >= 38)
return 0;
bitrate = rate [frmsizecod >> 1];
*pi_bit_rate = (bitrate * 1000) >> half;
switch (p_buf[4] & 0xc0) {
case 0:
*pi_sample_rate = 48000 >> half;
return 4 * bitrate;
case 0x40:
*pi_sample_rate = 44100 >> half;
return 2 * (320 * bitrate / 147 + (frmsizecod & 1));
case 0x80:
*pi_sample_rate = 32000 >> half;
return 6 * bitrate;
default:
return 0;
}
}
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