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vlc/modules/codec/a52.c

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/*****************************************************************************
* a52.c: parse A/52 audio sync info and packetize the stream
*****************************************************************************
* Copyright (C) 2001-2002 the VideoLAN team
* $Id$
*
* Authors: Stéphane Borel <stef@via.ecp.fr>
* Christophe Massiot <massiot@via.ecp.fr>
* Gildas Bazin <gbazin@videolan.org>
*
* 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., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
*****************************************************************************/
/*****************************************************************************
* Preamble
*****************************************************************************/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <vlc/vlc.h>
#include <vlc_plugin.h>
#include <vlc_codec.h>
#include <vlc_aout.h>
#include <vlc_input.h>
#include <vlc_block_helper.h>
#define A52_HEADER_SIZE 7
/*****************************************************************************
* decoder_sys_t : decoder descriptor
*****************************************************************************/
struct decoder_sys_t
{
/* Module mode */
bool b_packetizer;
/*
* Input properties
*/
int i_state;
block_bytestream_t bytestream;
/*
* Common properties
*/
audio_date_t end_date;
mtime_t i_pts;
int i_frame_size, i_bit_rate;
unsigned int i_rate, i_channels, i_channels_conf;
int i_input_rate;
};
enum {
STATE_NOSYNC,
STATE_SYNC,
STATE_HEADER,
STATE_NEXT_SYNC,
STATE_GET_DATA,
STATE_SEND_DATA
};
/****************************************************************************
* Local prototypes
****************************************************************************/
static int OpenDecoder ( vlc_object_t * );
static int OpenPacketizer( vlc_object_t * );
static void CloseDecoder ( vlc_object_t * );
static void *DecodeBlock ( decoder_t *, block_t ** );
static int SyncInfo ( const uint8_t *, unsigned int *, unsigned int *,
unsigned int *, int * );
static uint8_t *GetOutBuffer ( decoder_t *, void ** );
static aout_buffer_t *GetAoutBuffer( decoder_t * );
static block_t *GetSoutBuffer( decoder_t * );
/*****************************************************************************
* Module descriptor
*****************************************************************************/
vlc_module_begin();
set_description( N_("A/52 parser") );
set_capability( "decoder", 100 );
set_callbacks( OpenDecoder, CloseDecoder );
set_category( CAT_INPUT );
set_subcategory( SUBCAT_INPUT_ACODEC );
add_submodule();
set_description( N_("A/52 audio packetizer") );
set_capability( "packetizer", 10 );
set_callbacks( OpenPacketizer, CloseDecoder );
vlc_module_end();
/*****************************************************************************
* OpenDecoder: probe the decoder and return score
*****************************************************************************/
static int OpenDecoder( 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_FOURCC('a','5','2',' ')
&& p_dec->fmt_in.i_codec != VLC_FOURCC('a','5','2','b') )
{
return VLC_EGENERIC;
}
/* Allocate the memory needed to store the decoder's structure */
if( ( p_dec->p_sys = p_sys =
(decoder_sys_t *)malloc(sizeof(decoder_sys_t)) ) == NULL )
return VLC_ENOMEM;
/* Misc init */
p_sys->b_packetizer = false;
p_sys->i_state = STATE_NOSYNC;
aout_DateSet( &p_sys->end_date, 0 );
p_sys->bytestream = block_BytestreamInit();
p_sys->i_input_rate = INPUT_RATE_DEFAULT;
/* Set output properties */
p_dec->fmt_out.i_cat = AUDIO_ES;
p_dec->fmt_out.i_codec = VLC_FOURCC('a','5','2',' ');
p_dec->fmt_out.audio.i_rate = 0; /* So end_date gets initialized */
/* Set callback */
p_dec->pf_decode_audio = (aout_buffer_t *(*)(decoder_t *, block_t **))
DecodeBlock;
p_dec->pf_packetize = (block_t *(*)(decoder_t *, block_t **))
DecodeBlock;
return VLC_SUCCESS;
}
static int OpenPacketizer( vlc_object_t *p_this )
{
decoder_t *p_dec = (decoder_t*)p_this;
int i_ret = OpenDecoder( p_this );
if( i_ret == VLC_SUCCESS ) p_dec->p_sys->b_packetizer = true;
return i_ret;
}
/****************************************************************************
* DecodeBlock: the whole thing
****************************************************************************
* This function is called just after the thread is launched.
****************************************************************************/
static void *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
{
decoder_sys_t *p_sys = p_dec->p_sys;
uint8_t p_header[A52_HEADER_SIZE];
uint8_t *p_buf;
void *p_out_buffer;
if( !pp_block || !*pp_block ) return NULL;
if( (*pp_block)->i_flags&(BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
{
if( (*pp_block)->i_flags&BLOCK_FLAG_CORRUPTED )
{
p_sys->i_state = STATE_NOSYNC;
block_BytestreamFlush( &p_sys->bytestream );
}
// aout_DateSet( &p_sys->end_date, 0 );
block_Release( *pp_block );
return NULL;
}
if( !aout_DateGet( &p_sys->end_date ) && !(*pp_block)->i_pts )
{
/* We've just started the stream, wait for the first PTS. */
block_Release( *pp_block );
return NULL;
}
if( (*pp_block)->i_rate > 0 )
p_sys->i_input_rate = (*pp_block)->i_rate;
block_BytestreamPush( &p_sys->bytestream, *pp_block );
while( 1 )
{
switch( p_sys->i_state )
{
case STATE_NOSYNC:
while( block_PeekBytes( &p_sys->bytestream, p_header, 2 )
== VLC_SUCCESS )
{
if( p_header[0] == 0x0b && p_header[1] == 0x77 )
{
p_sys->i_state = STATE_SYNC;
break;
}
block_SkipByte( &p_sys->bytestream );
}
if( p_sys->i_state != STATE_SYNC )
{
block_BytestreamFlush( &p_sys->bytestream );
/* Need more data */
return NULL;
}
case STATE_SYNC:
/* New frame, set the Presentation Time Stamp */
p_sys->i_pts = p_sys->bytestream.p_block->i_pts;
if( p_sys->i_pts != 0 &&
p_sys->i_pts != aout_DateGet( &p_sys->end_date ) )
{
aout_DateSet( &p_sys->end_date, p_sys->i_pts );
}
p_sys->i_state = STATE_HEADER;
case STATE_HEADER:
/* Get A/52 frame header (A52_HEADER_SIZE bytes) */
if( block_PeekBytes( &p_sys->bytestream, p_header,
A52_HEADER_SIZE ) != VLC_SUCCESS )
{
/* Need more data */
return NULL;
}
/* Check if frame is valid and get frame info */
p_sys->i_frame_size = SyncInfo( p_header,
&p_sys->i_channels,
&p_sys->i_channels_conf,
&p_sys->i_rate,
&p_sys->i_bit_rate );
if( !p_sys->i_frame_size )
{
msg_Dbg( p_dec, "emulated sync word" );
block_SkipByte( &p_sys->bytestream );
p_sys->i_state = STATE_NOSYNC;
break;
}
p_sys->i_state = STATE_NEXT_SYNC;
case STATE_NEXT_SYNC:
/* TODO: If pp_block == NULL, flush the buffer without checking the
* next sync word */
/* Check if next expected frame contains the sync word */
if( block_PeekOffsetBytes( &p_sys->bytestream,
p_sys->i_frame_size, p_header, 2 )
!= VLC_SUCCESS )
{
/* Need more data */
return NULL;
}
if( p_sys->b_packetizer &&
p_header[0] == 0 && p_header[1] == 0 )
{
/* A52 wav files and audio CD's use stuffing */
p_sys->i_state = STATE_GET_DATA;
break;
}
if( p_header[0] != 0x0b || p_header[1] != 0x77 )
{
msg_Dbg( p_dec, "emulated sync word "
"(no sync on following frame)" );
p_sys->i_state = STATE_NOSYNC;
block_SkipByte( &p_sys->bytestream );
break;
}
p_sys->i_state = STATE_SEND_DATA;
break;
case STATE_GET_DATA:
/* Make sure we have enough data.
* (Not useful if we went through NEXT_SYNC) */
if( block_WaitBytes( &p_sys->bytestream,
p_sys->i_frame_size ) != VLC_SUCCESS )
{
/* Need more data */
return NULL;
}
p_sys->i_state = STATE_SEND_DATA;
case STATE_SEND_DATA:
if( !(p_buf = GetOutBuffer( p_dec, &p_out_buffer )) )
{
//p_dec->b_error = true;
return NULL;
}
/* Copy the whole frame into the buffer. When we reach this point
* we already know we have enough data available. */
block_GetBytes( &p_sys->bytestream, p_buf, p_sys->i_frame_size );
/* Make sure we don't reuse the same pts twice */
if( p_sys->i_pts == p_sys->bytestream.p_block->i_pts )
p_sys->i_pts = p_sys->bytestream.p_block->i_pts = 0;
/* So p_block doesn't get re-added several times */
*pp_block = block_BytestreamPop( &p_sys->bytestream );
p_sys->i_state = STATE_NOSYNC;
return p_out_buffer;
}
}
return NULL;
}
/*****************************************************************************
* CloseDecoder: clean up the decoder
*****************************************************************************/
static void CloseDecoder( vlc_object_t *p_this )
{
decoder_t *p_dec = (decoder_t*)p_this;
decoder_sys_t *p_sys = p_dec->p_sys;
block_BytestreamRelease( &p_sys->bytestream );
free( p_sys );
}
/*****************************************************************************
* GetOutBuffer:
*****************************************************************************/
static uint8_t *GetOutBuffer( decoder_t *p_dec, void **pp_out_buffer )
{
decoder_sys_t *p_sys = p_dec->p_sys;
uint8_t *p_buf;
if( p_dec->fmt_out.audio.i_rate != p_sys->i_rate )
{
msg_Info( p_dec, "A/52 channels:%d samplerate:%d bitrate:%d",
p_sys->i_channels, p_sys->i_rate, p_sys->i_bit_rate );
aout_DateInit( &p_sys->end_date, p_sys->i_rate );
aout_DateSet( &p_sys->end_date, p_sys->i_pts );
}
p_dec->fmt_out.audio.i_rate = p_sys->i_rate;
p_dec->fmt_out.audio.i_channels = p_sys->i_channels;
p_dec->fmt_out.audio.i_bytes_per_frame = p_sys->i_frame_size;
p_dec->fmt_out.audio.i_frame_length = A52_FRAME_NB;
p_dec->fmt_out.audio.i_original_channels = p_sys->i_channels_conf;
p_dec->fmt_out.audio.i_physical_channels =
p_sys->i_channels_conf & AOUT_CHAN_PHYSMASK;
p_dec->fmt_out.i_bitrate = p_sys->i_bit_rate;
if( p_sys->b_packetizer )
{
block_t *p_sout_buffer = GetSoutBuffer( p_dec );
p_buf = p_sout_buffer ? p_sout_buffer->p_buffer : NULL;
*pp_out_buffer = p_sout_buffer;
}
else
{
aout_buffer_t *p_aout_buffer = GetAoutBuffer( p_dec );
p_buf = p_aout_buffer ? p_aout_buffer->p_buffer : NULL;
*pp_out_buffer = p_aout_buffer;
}
return p_buf;
}
/*****************************************************************************
* GetAoutBuffer:
*****************************************************************************/
static aout_buffer_t *GetAoutBuffer( decoder_t *p_dec )
{
decoder_sys_t *p_sys = p_dec->p_sys;
aout_buffer_t *p_buf;
p_buf = p_dec->pf_aout_buffer_new( p_dec, A52_FRAME_NB );
if( p_buf == NULL ) return NULL;
p_buf->start_date = aout_DateGet( &p_sys->end_date );
p_buf->end_date = aout_DateIncrement( &p_sys->end_date,
A52_FRAME_NB * p_sys->i_input_rate / INPUT_RATE_DEFAULT );
return p_buf;
}
/*****************************************************************************
* GetSoutBuffer:
*****************************************************************************/
static block_t *GetSoutBuffer( decoder_t *p_dec )
{
decoder_sys_t *p_sys = p_dec->p_sys;
block_t *p_block;
p_block = block_New( p_dec, p_sys->i_frame_size );
if( p_block == NULL ) return NULL;
p_block->i_pts = p_block->i_dts = aout_DateGet( &p_sys->end_date );
p_block->i_length =
aout_DateIncrement( &p_sys->end_date,
A52_FRAME_NB * p_sys->i_input_rate / INPUT_RATE_DEFAULT ) -
p_block->i_pts;
return p_block;
}
/*****************************************************************************
* SyncInfo: parse A/52 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...
*****************************************************************************/
static int SyncInfo( const uint8_t * p_buf,
unsigned int * pi_channels,
unsigned int * pi_channels_conf,
unsigned int * pi_sample_rate, int * pi_bit_rate )
{
static const uint8_t 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 uint8_t 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) == 0x50 )
{
/* Dolby surround = stereo + Dolby */
*pi_channels = 2;
*pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
| AOUT_CHAN_DOLBYSTEREO;
}
else switch ( acmod )
{
case 0x0:
/* Dual-mono = stereo + dual-mono */
*pi_channels = 2;
*pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
| AOUT_CHAN_DUALMONO;
break;
case 0x1:
/* Mono */
*pi_channels = 1;
*pi_channels_conf = AOUT_CHAN_CENTER;
break;
case 0x2:
/* Stereo */
*pi_channels = 2;
*pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
break;
case 0x3:
/* 3F */
*pi_channels = 3;
*pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
| AOUT_CHAN_CENTER;
break;
case 0x4:
/* 2F1R */
*pi_channels = 3;
*pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
| AOUT_CHAN_REARCENTER;
break;
case 0x5:
/* 3F1R */
*pi_channels = 4;
*pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
| AOUT_CHAN_REARCENTER;
break;
case 0x6:
/* 2F2R */
*pi_channels = 4;
*pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
| AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT;
break;
case 0x7:
/* 3F2R */
*pi_channels = 5;
*pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
| AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT;
break;
default:
return 0;
}
if ( p_buf[6] & lfeon[acmod] )
{
(*pi_channels)++;
*pi_channels_conf |= 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;
}
}