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vlc/modules/codec/a52.c

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/*****************************************************************************
* a52.c: ATSC A/52 aka AC-3 decoder plugin for VLC.
* This plugin makes use of liba52 to decode A/52 audio
* (http://liba52.sf.net/).
*****************************************************************************
* Copyright (C) 2001-2009 VLC authors and VideoLAN
*
* Authors: Gildas Bazin <gbazin@videolan.org>
* Christophe Massiot <massiot@via.ecp.fr>
* Thomas Guillem <thomas@gllm.fr>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
*****************************************************************************/
/*****************************************************************************
* NOTA BENE: this module requires the linking against a library which is
* known to require licensing under the GNU General Public License version 2
* (or later). Therefore, the result of compiling this module will normally
* be subject to the terms of that later license.
*****************************************************************************/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <vlc_common.h>
#include <vlc_plugin.h>
#include <vlc_cpu.h>
#include <stdint.h> /* int16_t .. */
#ifdef USE_A52DEC_TREE /* liba52 header file */
# include "include/a52.h"
#else
# include "a52dec/a52.h"
#endif
#include <vlc_aout.h>
#include <vlc_block.h>
#include <vlc_codec.h>
static int Open ( vlc_object_t * );
static void Close( vlc_object_t * );
typedef struct
{
a52_state_t *p_liba52; /* liba52 internal structure */
bool b_dynrng; /* see below */
int i_flags; /* liba52 flags, see a52dec/doc/liba52.txt */
bool b_dontwarn;
int i_nb_channels; /* number of float32 per sample */
uint8_t pi_chan_table[AOUT_CHAN_MAX]; /* channel reordering */
bool b_synced;
} decoder_sys_t;
#define DYNRNG_TEXT N_("A/52 dynamic range compression")
#define DYNRNG_LONGTEXT N_( \
"Dynamic range compression makes the loud sounds softer, and the soft " \
"sounds louder, so you can more easily listen to the stream in a noisy " \
"environment without disturbing anyone. If you disable the dynamic range "\
"compression the playback will be more adapted to a movie theater or a " \
"listening room.")
vlc_module_begin ()
set_shortname( "A/52" )
set_description( N_("ATSC A/52 (AC-3) audio decoder") )
set_subcategory( SUBCAT_INPUT_ACODEC )
add_bool( "a52-dynrng", true, DYNRNG_TEXT, DYNRNG_LONGTEXT )
set_capability( "audio decoder", 60 )
set_callbacks( Open, Close )
vlc_module_end ()
/*
* helper function to interleave channels
*/
static void Interleave( sample_t *restrict p_out, const sample_t *restrict p_in,
unsigned i_nb_channels, uint8_t *restrict pi_chan_table )
{
/* We do not only have to interleave, but also reorder the channels */
for( unsigned j = 0; j < i_nb_channels; j++ )
{
for( unsigned i = 0; i < 256; i++ )
{
#ifdef LIBA52_FIXED
union { uint32_t u; int32_t i; } spl;
spl.u = ((uint32_t)p_in[j * 256 + i]) << 4;
p_out[i * i_nb_channels + pi_chan_table[j]] = spl.i;
#else
p_out[i * i_nb_channels + pi_chan_table[j]] = p_in[j * 256 + i];
#endif
}
}
}
/*
* helper function to duplicate a unique channel
*/
static void Duplicate( sample_t *restrict p_out, const sample_t *restrict p_in )
{
for( unsigned i = 256; i--; )
{
#ifdef LIBA52_FIXED
union { uint32_t u; int32_t i; } spl;
spl.u = ((uint32_t)*(p_in++)) << 4;
*p_out++ = spl.i;
*p_out++ = spl.i;
#else
sample_t s = *(p_in++);
*p_out++ = s;
*p_out++ = s;
#endif
}
}
static int Decode( decoder_t *p_dec, block_t *p_in_buf )
{
decoder_sys_t *p_sys = p_dec->p_sys;
if (p_in_buf == NULL) /* No drain */
return VLCDEC_SUCCESS;
#ifdef LIBA52_FIXED
sample_t i_sample_level = (1 << 24);
#else
sample_t i_sample_level = 1;
#endif
int i_flags = p_sys->i_flags;
size_t i_bytes_per_block = 256 * p_sys->i_nb_channels * sizeof(sample_t);
/* Every A/52 frame is composed of 6 blocks, each with an output of 256
* samples for each channel. */
block_t *p_out_buf = block_Alloc( 6 * i_bytes_per_block );
if( unlikely(p_out_buf == NULL) )
{
block_Release( p_in_buf );
return VLCDEC_SUCCESS;
}
/* Do the actual decoding now. */
a52_frame( p_sys->p_liba52, p_in_buf->p_buffer,
&i_flags, &i_sample_level, 0 );
if ( (i_flags & A52_CHANNEL_MASK) != (p_sys->i_flags & A52_CHANNEL_MASK)
&& !p_sys->b_dontwarn )
{
msg_Warn( p_dec,
"liba52 couldn't do the requested downmix 0x%x->0x%x",
p_sys->i_flags & A52_CHANNEL_MASK,
i_flags & A52_CHANNEL_MASK );
p_sys->b_dontwarn = 1;
}
if( !p_sys->b_dynrng )
{
a52_dynrng( p_sys->p_liba52, NULL, NULL );
}
for( unsigned i = 0; i < 6; i++ )
{
if( a52_block( p_sys->p_liba52 ) )
msg_Warn( p_dec, "a52_block failed for block %d", i );
sample_t *p_samples = a52_samples( p_sys->p_liba52 );
if ( ((p_sys->i_flags & A52_CHANNEL_MASK) == A52_CHANNEL1
|| (p_sys->i_flags & A52_CHANNEL_MASK) == A52_CHANNEL2
|| (p_sys->i_flags & A52_CHANNEL_MASK) == A52_MONO)
&& (p_dec->fmt_out.audio.i_physical_channels
& (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT)) )
{
Duplicate( (sample_t *)(p_out_buf->p_buffer + i * i_bytes_per_block),
p_samples );
}
else
{
/* Interleave the *$£%ù samples. */
Interleave( (sample_t *)(p_out_buf->p_buffer + i * i_bytes_per_block),
p_samples, p_sys->i_nb_channels, p_sys->pi_chan_table);
}
}
p_out_buf->i_nb_samples = A52_FRAME_NB; /* 6 * 256 */
p_out_buf->i_dts = p_in_buf->i_dts;
p_out_buf->i_pts = p_in_buf->i_pts;
p_out_buf->i_length = p_in_buf->i_length;
block_Release( p_in_buf );
decoder_QueueAudio( p_dec, p_out_buf );
return VLCDEC_SUCCESS;
}
static int channels_vlc2a52( const audio_format_t *p_audio, int *p_flags )
{
int i_flags = 0;
switch ( p_audio->i_physical_channels & ~AOUT_CHAN_LFE )
{
case AOUT_CHAN_CENTER:
if ( (p_audio->i_physical_channels & AOUT_CHAN_CENTER)
|| (p_audio->i_physical_channels
& (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT)) )
i_flags = A52_MONO;
else if ( p_audio->i_physical_channels & AOUT_CHAN_LEFT )
i_flags = A52_CHANNEL1;
else
i_flags = A52_CHANNEL2;
break;
case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT:
if ( p_audio->i_chan_mode & AOUT_CHANMODE_DOLBYSTEREO )
i_flags = A52_DOLBY;
else if ( p_audio->i_chan_mode & AOUT_CHANMODE_DUALMONO )
i_flags = A52_CHANNEL;
else if ( !(p_audio->i_physical_channels & AOUT_CHAN_RIGHT) )
i_flags = A52_CHANNEL1;
else if ( !(p_audio->i_physical_channels & AOUT_CHAN_LEFT) )
i_flags = A52_CHANNEL2;
else
i_flags = A52_STEREO;
break;
case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER:
i_flags = A52_3F;
break;
case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_REARCENTER:
i_flags = A52_2F1R;
break;
case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
| AOUT_CHAN_REARCENTER:
i_flags = A52_3F1R;
break;
case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
| AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT:
i_flags = A52_2F2R;
break;
case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
| AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT:
i_flags = A52_3F2R;
break;
default:
return VLC_EGENERIC;
}
if ( p_audio->i_physical_channels & AOUT_CHAN_LFE )
i_flags |= A52_LFE;
*p_flags = i_flags;
return VLC_SUCCESS;
}
static int Open( vlc_object_t *p_this )
{
decoder_t *p_dec = (decoder_t *)p_this;
decoder_sys_t *p_sys;
if( p_dec->fmt_in->i_codec != VLC_CODEC_A52
|| p_dec->fmt_in->audio.i_rate == 0
|| p_dec->fmt_in->audio.i_physical_channels == 0
|| p_dec->fmt_in->audio.i_bytes_per_frame == 0
|| p_dec->fmt_in->audio.i_frame_length == 0 )
return VLC_EGENERIC;
/* Allocate the memory needed to store the module's structure */
p_dec->p_sys = p_sys = malloc( sizeof(decoder_sys_t) );
if( p_sys == NULL )
return VLC_ENOMEM;
p_sys->b_dynrng = var_InheritBool( p_this, "a52-dynrng" );
p_sys->b_dontwarn = 0;
p_sys->i_nb_channels = aout_FormatNbChannels( &p_dec->fmt_in->audio );
if( channels_vlc2a52( &p_dec->fmt_in->audio, &p_sys->i_flags )
!= VLC_SUCCESS )
{
msg_Warn( p_this, "unknown sample format!" );
free( p_sys );
return VLC_EGENERIC;
}
p_sys->i_flags |= A52_ADJUST_LEVEL;
/* Initialize liba52 */
p_sys->p_liba52 = a52_init( 0 );
if( p_sys->p_liba52 == NULL )
{
msg_Err( p_this, "unable to initialize liba52" );
free( p_sys );
return VLC_EGENERIC;
}
static const uint32_t pi_channels_in[] = {
AOUT_CHAN_LFE, AOUT_CHAN_LEFT, AOUT_CHAN_CENTER, AOUT_CHAN_RIGHT,
AOUT_CHAN_REARLEFT, AOUT_CHAN_REARCENTER, AOUT_CHAN_REARRIGHT, 0
};
aout_CheckChannelReorder( pi_channels_in, NULL,
p_dec->fmt_in->audio.i_physical_channels,
p_sys->pi_chan_table );
p_dec->fmt_out.audio = p_dec->fmt_in->audio;
#ifdef LIBA52_FIXED
p_dec->fmt_out.audio.i_format = VLC_CODEC_S32N;
#else
p_dec->fmt_out.audio.i_format = VLC_CODEC_FL32;
#endif
p_dec->fmt_out.i_codec = p_dec->fmt_out.audio.i_format;
aout_FormatPrepare( &p_dec->fmt_out.audio );
if( decoder_UpdateAudioFormat( p_dec ) )
{
Close( p_this );
return VLC_EGENERIC;
}
p_dec->pf_decode = Decode;
p_dec->pf_flush = NULL;
return VLC_SUCCESS;
}
static void Close( vlc_object_t *p_this )
{
decoder_t *p_dec = (decoder_t *)p_this;
decoder_sys_t *p_sys = p_dec->p_sys;
a52_free( p_sys->p_liba52 );
free( p_sys );
}
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