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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 VLC authors and VideoLAN
* $Id$
*
* 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 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.
*****************************************************************************/
/*****************************************************************************
* Preamble
*****************************************************************************/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <vlc_common.h>
#include <vlc_plugin.h>
#include <vlc_codec.h>
#include <vlc_block_helper.h>
#include <vlc_modules.h>
#include "a52.h"
#include "../packetizer/packetizer_helper.h"
/*****************************************************************************
* Module descriptor
*****************************************************************************/
static int OpenDecoder ( vlc_object_t * );
static int OpenPacketizer( vlc_object_t * );
static void CloseCommon ( vlc_object_t * );
vlc_module_begin ()
set_description( N_("A/52 parser") )
set_capability( "decoder", 100 )
set_callbacks( OpenDecoder, CloseCommon )
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, CloseCommon )
vlc_module_end ()
/*****************************************************************************
* 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
*/
date_t end_date;
mtime_t i_pts;
vlc_a52_header_t frame;
};
/****************************************************************************
* Local prototypes
****************************************************************************/
static block_t *DecodeBlock ( decoder_t *, block_t ** );
static uint8_t *GetOutBuffer ( decoder_t *, block_t ** );
static block_t *GetAoutBuffer( decoder_t * );
static block_t *GetSoutBuffer( decoder_t * );
/*****************************************************************************
* OpenCommon: probe the decoder/packetizer and return score
*****************************************************************************/
static int OpenCommon( vlc_object_t *p_this, bool b_packetizer )
{
decoder_t *p_dec = (decoder_t*)p_this;
decoder_sys_t *p_sys;
vlc_fourcc_t i_codec;
switch( p_dec->fmt_in.i_codec )
{
case VLC_CODEC_A52:
i_codec = VLC_CODEC_A52;
break;
case VLC_CODEC_EAC3:
/* XXX ugly hack, a52 does not support eac3 so no eac3 pass-through
* support */
if( !b_packetizer )
return VLC_EGENERIC;
i_codec = VLC_CODEC_EAC3;
break;
default:
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 = b_packetizer;
p_sys->i_state = STATE_NOSYNC;
date_Set( &p_sys->end_date, 0 );
p_sys->i_pts = VLC_TS_INVALID;
block_BytestreamInit( &p_sys->bytestream );
/* Set output properties */
p_dec->fmt_out.i_cat = AUDIO_ES;
p_dec->fmt_out.i_codec = i_codec;
p_dec->fmt_out.audio.i_rate = 0; /* So end_date gets initialized */
p_dec->fmt_out.audio.i_bytes_per_frame = 0;
/* Set callback */
if( b_packetizer )
p_dec->pf_packetize = DecodeBlock;
else
p_dec->pf_decode_audio = DecodeBlock;
return VLC_SUCCESS;
}
static int OpenDecoder( vlc_object_t *p_this )
{
/* HACK: Don't use this codec if we don't have an a52 audio filter */
if( !module_exists( "a52tofloat32" ) )
return VLC_EGENERIC;
return OpenCommon( p_this, false );
}
static int OpenPacketizer( vlc_object_t *p_this )
{
return OpenCommon( p_this, true );
}
/****************************************************************************
* DecodeBlock: the whole thing
****************************************************************************
* This function is called just after the thread is launched.
****************************************************************************/
static block_t *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
{
decoder_sys_t *p_sys = p_dec->p_sys;
uint8_t p_header[VLC_A52_HEADER_SIZE];
uint8_t *p_buf;
block_t *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_BytestreamEmpty( &p_sys->bytestream );
}
date_Set( &p_sys->end_date, 0 );
block_Release( *pp_block );
return NULL;
}
if( !date_Get( &p_sys->end_date ) && (*pp_block)->i_pts <= VLC_TS_INVALID)
{
/* We've just started the stream, wait for the first PTS. */
block_Release( *pp_block );
return NULL;
}
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 > VLC_TS_INVALID &&
p_sys->i_pts != date_Get( &p_sys->end_date ) )
{
date_Set( &p_sys->end_date, p_sys->i_pts );
}
p_sys->i_state = STATE_HEADER;
case STATE_HEADER:
/* Get A/52 frame header (VLC_A52_HEADER_SIZE bytes) */
if( block_PeekBytes( &p_sys->bytestream, p_header,
VLC_A52_HEADER_SIZE ) != VLC_SUCCESS )
{
/* Need more data */
return NULL;
}
/* Check if frame is valid and get frame info */
if( vlc_a52_header_Parse( &p_sys->frame, p_header, VLC_A52_HEADER_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->frame.i_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->frame.i_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, __MIN( p_sys->frame.i_size, p_out_buffer->i_buffer ) );
/* 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 = VLC_TS_INVALID;
/* 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;
}
}
}
/*****************************************************************************
* CloseCommon: clean up the decoder
*****************************************************************************/
static void CloseCommon( 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, block_t **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->frame.i_rate )
{
msg_Dbg( p_dec, "A/52 channels:%d samplerate:%d bitrate:%d",
p_sys->frame.i_channels, p_sys->frame.i_rate, p_sys->frame.i_bitrate );
date_Init( &p_sys->end_date, p_sys->frame.i_rate, 1 );
date_Set( &p_sys->end_date, p_sys->i_pts );
}
p_dec->fmt_out.audio.i_rate = p_sys->frame.i_rate;
p_dec->fmt_out.audio.i_channels = p_sys->frame.i_channels;
if( p_dec->fmt_out.audio.i_bytes_per_frame < p_sys->frame.i_size )
p_dec->fmt_out.audio.i_bytes_per_frame = p_sys->frame.i_size;
p_dec->fmt_out.audio.i_frame_length = p_sys->frame.i_samples;
p_dec->fmt_out.audio.i_original_channels = p_sys->frame.i_channels_conf;
p_dec->fmt_out.audio.i_physical_channels =
p_sys->frame.i_channels_conf & AOUT_CHAN_PHYSMASK;
p_dec->fmt_out.i_bitrate = p_sys->frame.i_bitrate;
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
{
block_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 block_t *GetAoutBuffer( decoder_t *p_dec )
{
decoder_sys_t *p_sys = p_dec->p_sys;
block_t *p_buf = decoder_NewAudioBuffer( p_dec, p_sys->frame.i_samples );
if( p_buf )
{
p_buf->i_pts = date_Get( &p_sys->end_date );
p_buf->i_length = date_Increment( &p_sys->end_date,
p_sys->frame.i_samples ) - p_buf->i_pts;
}
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 = block_Alloc( p_sys->frame.i_size );
if( p_block )
{
p_block->i_pts = p_block->i_dts = date_Get( &p_sys->end_date );
p_block->i_length =
date_Increment( &p_sys->end_date, p_sys->frame.i_samples ) - p_block->i_pts;
}
return p_block;
}