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/*****************************************************************************
* mad.c: MPEG-1 & 2 audio layer I, II, III + MPEG 2.5 decoder,
* using MAD (MPEG Audio Decoder)
*****************************************************************************
* Copyright (C) 2001-2016 VLC authors and VideoLAN
*
* Authors: Christophe Massiot <massiot@via.ecp.fr>
* Jean-Paul Saman <jpsaman _at_ videolan _dot_ org>
*
* 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.
*****************************************************************************/
/*****************************************************************************
* Preamble
*****************************************************************************/
#include <mad.h>
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <assert.h>
#include <vlc_common.h>
#include <vlc_plugin.h>
#include <vlc_block.h>
#include <vlc_aout.h>
#include <vlc_codec.h>
#define MAD_BUFFER_GUARD 8
/*****************************************************************************
* Local prototypes
*****************************************************************************/
static int Open ( vlc_object_t * );
static void Close( vlc_object_t * );
/*****************************************************************************
* Local structures
*****************************************************************************/
typedef struct
{
struct mad_stream mad_stream;
struct mad_frame mad_frame;
struct mad_synth mad_synth;
int i_reject_count;
block_t *p_last_buf;
} decoder_sys_t;
/*****************************************************************************
* Module descriptor
*****************************************************************************/
vlc_module_begin ()
set_subcategory( SUBCAT_INPUT_ACODEC )
set_description( N_("MPEG audio layer I/II/III decoder") )
set_capability( "audio decoder", 99 )
set_callbacks( Open, Close )
vlc_module_end ()
/*****************************************************************************
*
*****************************************************************************/
static void PrepareDecoderDiscontinuityGlitch( decoder_sys_t *p_sys )
{
mad_frame_mute( &p_sys->mad_frame );
mad_synth_mute( &p_sys->mad_synth );
p_sys->i_reject_count = 3;
}
/*****************************************************************************
* DecodeBlock: decode an MPEG audio frame.
*****************************************************************************/
static block_t *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
{
decoder_sys_t *p_sys = p_dec->p_sys;
block_t *p_out_buf = NULL, *p_last_buf = NULL;
if( !pp_block )
{
/* Drain */
p_last_buf = p_sys->p_last_buf;
p_sys->p_last_buf = NULL;
if( !p_last_buf )
return NULL;
}
else
{
if( !*pp_block )
return NULL;
block_t *p_in_buf = *pp_block;
*pp_block = NULL;
if( p_in_buf->i_buffer < MAD_BUFFER_GUARD )
{
block_Release( p_in_buf );
return NULL;
}
/* Buffers passed to the mad_stream_buffer() function need to ends with
* the header (MAD_BUFFER_GUARD) of the following block. Therefore,
* this DecodeBlock() function will always return the output buffer
* corresponding to the last input buffer. */
if( !p_sys->p_last_buf )
{
/* Wait for the next block */
p_sys->p_last_buf = p_in_buf;
return NULL;
}
p_last_buf = p_sys->p_last_buf;
p_sys->p_last_buf = p_in_buf;
/* Put the header of the current buffer at the end of the last one.
* Normally, this won't do a real realloc() since VLC blocks are
* allocated with pre and post padding */
p_last_buf = block_Realloc( p_last_buf, 0,
p_last_buf->i_buffer + MAD_BUFFER_GUARD );
if( !p_last_buf )
return NULL;
memcpy( &p_last_buf->p_buffer[p_last_buf->i_buffer - MAD_BUFFER_GUARD],
p_in_buf->p_buffer, MAD_BUFFER_GUARD);
}
mad_stream_buffer( &p_sys->mad_stream, p_last_buf->p_buffer,
p_last_buf->i_buffer );
/* Do the actual decoding now (ignore EOF error when draining). */
if ( mad_frame_decode( &p_sys->mad_frame, &p_sys->mad_stream ) == -1
&& p_sys->i_reject_count == 0
&& ( pp_block != NULL || p_sys->mad_stream.error != MAD_ERROR_BUFLEN ) )
{
msg_Err( p_dec, "libmad error: %s",
mad_stream_errorstr( &p_sys->mad_stream ) );
if( !MAD_RECOVERABLE( p_sys->mad_stream.error ) )
PrepareDecoderDiscontinuityGlitch( p_sys );
}
else if( p_last_buf->i_flags & BLOCK_FLAG_DISCONTINUITY )
{
PrepareDecoderDiscontinuityGlitch( p_sys );
}
if( p_sys->i_reject_count > 1 )
goto reject;
mad_synth_frame( &p_sys->mad_synth, &p_sys->mad_frame );
if( p_sys->i_reject_count > 0 )
goto reject;
struct mad_pcm * p_pcm = &p_sys->mad_synth.pcm;
unsigned int i_samples = p_pcm->length;
mad_fixed_t const * p_left = p_pcm->samples[0];
mad_fixed_t const * p_right = p_pcm->samples[1];
p_out_buf = decoder_NewAudioBuffer( p_dec, i_samples );
if( !p_out_buf )
goto end;
p_out_buf->i_dts = p_last_buf->i_dts;
p_out_buf->i_pts = p_last_buf->i_pts;
p_out_buf->i_length = p_last_buf->i_length;
float *p_samples = (float *)p_out_buf->p_buffer;
if (p_pcm->channels > p_dec->fmt_out.audio.i_channels)
{
msg_Err( p_dec, "wrong channels count (corrupt stream?): %u > %u",
p_pcm->channels, p_dec->fmt_out.audio.i_channels);
PrepareDecoderDiscontinuityGlitch( p_sys );
goto reject;
}
if( i_samples != p_out_buf->i_nb_samples )
{
msg_Err( p_dec, "unexpected samples count (corrupt stream?): "
"%u / %u", i_samples, p_out_buf->i_nb_samples );
PrepareDecoderDiscontinuityGlitch( p_sys );
goto reject;
}
/* Interleave and keep buffers in mad_fixed_t format */
if ( p_pcm->channels == 2 )
{
while ( i_samples-- )
{
//assert( *p_left < MAD_F_ONE );
//assert( *p_left >= -MAD_F_ONE );
//assert( *p_right < MAD_F_ONE );
//assert( *p_right >= -MAD_F_ONE );
*p_samples++ = (float)*p_left++ / (float)MAD_F_ONE;
*p_samples++ = (float)*p_right++ / (float)MAD_F_ONE;
}
}
else
{
assert( p_pcm->channels == 1 );
while ( i_samples-- )
{
//assert( *p_left < MAD_F_ONE );
//assert( *p_left >= -MAD_F_ONE );
*p_samples++ = (float)*p_left++ / (float)MAD_F_ONE;
}
}
end:
block_Release( p_last_buf );
return p_out_buf;
reject:
p_sys->i_reject_count--;
if( p_out_buf )
{
block_Release( p_out_buf );
p_out_buf = NULL;
}
goto end;
}
static int DecodeAudio( decoder_t *p_dec, block_t *p_block )
{
block_t **pp_block = p_block ? &p_block : NULL, *p_out;
while( ( p_out = DecodeBlock( p_dec, pp_block ) ) != NULL )
decoder_QueueAudio( p_dec, p_out );
return VLCDEC_SUCCESS;
}
static void DecodeFlush( decoder_t *p_dec )
{
decoder_sys_t *p_sys = p_dec->p_sys;
if( p_sys->p_last_buf )
block_Release( p_sys->p_last_buf );
p_sys->p_last_buf = NULL;
PrepareDecoderDiscontinuityGlitch( p_sys );
}
/*****************************************************************************
* Open:
*****************************************************************************/
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_MPGA
&& p_dec->fmt_in->i_codec != VLC_CODEC_MP3
&& p_dec->fmt_in->i_codec != VLC_FOURCC('m','p','g','3') )
|| 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_sys = p_dec->p_sys = malloc( sizeof(decoder_sys_t) );
if( p_sys == NULL )
return VLC_ENOMEM;
p_sys->i_reject_count = 0;
p_sys->p_last_buf = NULL;
/* Initialize libmad */
mad_stream_init( &p_sys->mad_stream );
mad_frame_init( &p_sys->mad_frame );
mad_synth_init( &p_sys->mad_synth );
mad_stream_options( &p_sys->mad_stream, MAD_OPTION_IGNORECRC );
p_dec->fmt_out.audio = p_dec->fmt_in->audio;
p_dec->fmt_out.audio.i_format = VLC_CODEC_FL32;
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 = DecodeAudio;
p_dec->pf_flush = DecodeFlush;
return VLC_SUCCESS;
}
/*****************************************************************************
* Close : deallocate data structures
*****************************************************************************/
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;
mad_synth_finish( &p_sys->mad_synth );
mad_frame_finish( &p_sys->mad_frame );
mad_stream_finish( &p_sys->mad_stream );
if( p_sys->p_last_buf )
block_Release( p_sys->p_last_buf );
free( p_sys );
}