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vlc/modules/codec/mpeg_audio.c

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/*****************************************************************************
* mpeg_audio.c: parse MPEG audio sync info and packetize the stream
*****************************************************************************
* Copyright (C) 2001-2003 VLC authors and VideoLAN
* $Id$
*
* Authors: Laurent Aimar <fenrir@via.ecp.fr>
* Eric Petit <titer@videolan.org>
* 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_aout.h>
#include <vlc_modules.h>
#include <assert.h>
#include <vlc_block_helper.h>
#include "../packetizer/packetizer_helper.h"
/*****************************************************************************
* decoder_sys_t : decoder descriptor
*****************************************************************************/
struct decoder_sys_t
{
#ifdef HAVE_MPGA_FILTER
/* Module mode */
bool b_packetizer;
#endif
/*
* Input properties
*/
int i_state;
block_bytestream_t bytestream;
/*
* Common properties
*/
date_t end_date;
mtime_t i_pts;
int i_frame_size, i_free_frame_size;
unsigned int i_channels_conf, i_channels;
unsigned int i_rate, i_max_frame_size, i_frame_length;
unsigned int i_layer, i_bit_rate;
bool b_discontinuity;
};
/* This isn't the place to put mad-specific stuff. However, it makes the
* mad plug-in's life much easier if we put 8 extra bytes at the end of the
* buffer, because that way it doesn't have to copy the block_t to a bigger
* buffer. This has no implication on other plug-ins, and we only lose 8 bytes
* per frame. --Meuuh */
#define MAD_BUFFER_GUARD 8
#define MPGA_HEADER_SIZE 4
/****************************************************************************
* Local prototypes
****************************************************************************/
#ifdef HAVE_MPGA_FILTER
static int OpenDecoder ( vlc_object_t * );
static block_t *GetAoutBuffer( decoder_t * );
#endif
static int Open( vlc_object_t * );
static block_t *DecodeBlock ( decoder_t *, block_t ** );
static uint8_t *GetOutBuffer ( decoder_t *, block_t ** );
static block_t *GetSoutBuffer( decoder_t * );
static void Close( vlc_object_t * );
static int SyncInfo( uint32_t i_header, unsigned int * pi_channels,
unsigned int * pi_channels_conf,
unsigned int * pi_sample_rate, unsigned int * pi_bit_rate,
unsigned int * pi_frame_length,
unsigned int * pi_max_frame_size,
unsigned int * pi_layer );
/*****************************************************************************
* Module descriptor
*****************************************************************************/
vlc_module_begin ()
set_category( CAT_INPUT )
set_subcategory( SUBCAT_INPUT_ACODEC )
set_description( N_("MPEG audio layer I/II/III packetizer") )
set_capability( "packetizer", 10 )
set_callbacks( Open, Close )
#ifdef HAVE_MPGA_FILTER
add_submodule ()
set_description( N_("MPEG audio layer I/II/III decoder") )
set_capability( "decoder", 100 )
set_callbacks( OpenDecoder, Close )
#endif
vlc_module_end ()
/*****************************************************************************
* Open: probe the decoder and return score
*****************************************************************************/
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 ) )
{
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 */
#ifdef HAVE_MPGA_FILTER
p_sys->b_packetizer = true;
#endif
p_sys->i_state = STATE_NOSYNC;
date_Set( &p_sys->end_date, 0 );
block_BytestreamInit( &p_sys->bytestream );
p_sys->i_pts = VLC_TS_INVALID;
p_sys->b_discontinuity = false;
p_sys->i_frame_size = 0;
p_sys->i_channels_conf = p_sys->i_channels = p_sys->i_rate =
p_sys->i_max_frame_size = p_sys->i_frame_length = p_sys->i_layer =
p_sys->i_bit_rate = 0;
/* Set output properties */
p_dec->fmt_out.i_cat = AUDIO_ES;
p_dec->fmt_out.i_codec = VLC_CODEC_MPGA;
p_dec->fmt_out.audio.i_rate = 0; /* So end_date gets initialized */
/* Set callback */
p_dec->pf_decode_audio = DecodeBlock;
p_dec->pf_packetize = DecodeBlock;
/* Start with the minimum size for a free bitrate frame */
p_sys->i_free_frame_size = MPGA_HEADER_SIZE;
return VLC_SUCCESS;
}
#ifdef HAVE_MPGA_FILTER
static int OpenDecoder( vlc_object_t *p_this )
{
decoder_t *p_dec = (decoder_t *)p_this;
/* HACK: Don't use this codec if we don't have an mpga audio filter */
if( !module_exists( "mad" ) )
return VLC_EGENERIC;
int i_ret = Open( p_this );
if( i_ret != VLC_SUCCESS )
return i_ret;
p_dec->p_sys->b_packetizer = false;
return VLC_SUCCESS;
}
#endif
/****************************************************************************
* 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[MAD_BUFFER_GUARD];
uint32_t i_header;
uint8_t *p_buf;
block_t *p_out_buffer;
block_t *p_block = pp_block ? *pp_block : NULL;
if (p_block) {
if( p_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( p_block );
return NULL;
}
if( p_block->i_flags & BLOCK_FLAG_DISCONTINUITY )
{
date_Set( &p_sys->end_date, 0 );
p_sys->b_discontinuity = true;
}
if( !date_Get( &p_sys->end_date ) && p_block->i_pts <= VLC_TS_INVALID )
{
/* We've just started the stream, wait for the first PTS. */
msg_Dbg( p_dec, "waiting for PTS" );
block_Release( p_block );
return NULL;
}
block_BytestreamPush( &p_sys->bytestream, p_block );
} else if (p_sys->i_frame_size)
p_sys->i_state = STATE_SEND_DATA; /* return all the data we have left */
else
return NULL;
while( 1 )
{
switch( p_sys->i_state )
{
case STATE_NOSYNC:
while( block_PeekBytes( &p_sys->bytestream, p_header, 2 )
== VLC_SUCCESS )
{
/* Look for sync word - should be 0xffe */
if( p_header[0] == 0xff && (p_header[1] & 0xe0) == 0xe0 )
{
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 MPGA frame header (MPGA_HEADER_SIZE bytes) */
if( block_PeekBytes( &p_sys->bytestream, p_header,
MPGA_HEADER_SIZE ) != VLC_SUCCESS )
{
/* Need more data */
return NULL;
}
/* Build frame header */
i_header = GetDWBE(p_header);
/* Check if frame is valid and get frame info */
p_sys->i_frame_size = SyncInfo( i_header,
&p_sys->i_channels,
&p_sys->i_channels_conf,
&p_sys->i_rate,
&p_sys->i_bit_rate,
&p_sys->i_frame_length,
&p_sys->i_max_frame_size,
&p_sys->i_layer );
p_dec->fmt_in.i_profile = p_sys->i_layer;
if( p_sys->i_frame_size == -1 )
{
msg_Dbg( p_dec, "emulated startcode" );
block_SkipByte( &p_sys->bytestream );
p_sys->i_state = STATE_NOSYNC;
break;
}
if( p_sys->i_bit_rate == 0 )
{
/* Free bitrate, but 99% emulated startcode :( */
if( p_dec->p_sys->i_free_frame_size == MPGA_HEADER_SIZE )
{
msg_Dbg( p_dec, "free bitrate mode");
}
/* The -1 below is to account for the frame padding */
p_sys->i_frame_size = p_sys->i_free_frame_size - 1;
}
p_sys->i_state = STATE_NEXT_SYNC;
case STATE_NEXT_SYNC:
/* TODO: If p_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,
MAD_BUFFER_GUARD ) != VLC_SUCCESS )
{
/* Need more data */
return NULL;
}
if( p_header[0] == 0xff && (p_header[1] & 0xe0) == 0xe0 )
{
/* Startcode is fine, let's try the header as an extra check */
int i_next_frame_size;
unsigned int i_next_channels, i_next_channels_conf;
unsigned int i_next_rate, i_next_bit_rate;
unsigned int i_next_frame_length, i_next_max_frame_size;
unsigned int i_next_layer;
/* Build frame header */
i_header = GetDWBE(p_header);
i_next_frame_size = SyncInfo( i_header,
&i_next_channels,
&i_next_channels_conf,
&i_next_rate,
&i_next_bit_rate,
&i_next_frame_length,
&i_next_max_frame_size,
&i_next_layer );
/* Free bitrate only */
if( p_sys->i_bit_rate == 0 && i_next_frame_size == -1 )
{
if( (unsigned int)p_sys->i_frame_size >
p_sys->i_max_frame_size )
{
msg_Dbg( p_dec, "frame too big %d > %d "
"(emulated startcode ?)", p_sys->i_frame_size,
p_sys->i_max_frame_size );
block_SkipByte( &p_sys->bytestream );
p_sys->i_state = STATE_NOSYNC;
p_sys->i_free_frame_size = MPGA_HEADER_SIZE;
break;
}
p_sys->i_frame_size++;
break;
}
if( i_next_frame_size == -1 )
{
msg_Dbg( p_dec, "emulated startcode on next frame" );
block_SkipByte( &p_sys->bytestream );
p_sys->i_state = STATE_NOSYNC;
break;
}
/* Check info is in sync with previous one */
if( i_next_channels_conf != p_sys->i_channels_conf ||
i_next_rate != p_sys->i_rate ||
i_next_layer != p_sys->i_layer ||
i_next_frame_length != p_sys->i_frame_length )
{
/* Free bitrate only */
if( p_sys->i_bit_rate == 0 )
{
p_sys->i_frame_size++;
break;
}
msg_Dbg( p_dec, "parameters changed unexpectedly "
"(emulated startcode ?)" );
block_SkipByte( &p_sys->bytestream );
p_sys->i_state = STATE_NOSYNC;
break;
}
/* Free bitrate only */
if( p_sys->i_bit_rate == 0 )
{
if( i_next_bit_rate != 0 )
{
p_sys->i_frame_size++;
break;
}
}
}
else
{
/* Free bitrate only */
if( p_sys->i_bit_rate == 0 )
{
if( (unsigned int)p_sys->i_frame_size >
p_sys->i_max_frame_size )
{
msg_Dbg( p_dec, "frame too big %d > %d "
"(emulated startcode ?)", p_sys->i_frame_size,
p_sys->i_max_frame_size );
block_SkipByte( &p_sys->bytestream );
p_sys->i_state = STATE_NOSYNC;
p_sys->i_free_frame_size = MPGA_HEADER_SIZE;
break;
}
p_sys->i_frame_size++;
break;
}
msg_Dbg( p_dec, "emulated startcode "
"(no startcode 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;
}
/* Free bitrate only */
if( p_sys->i_bit_rate == 0 )
{
p_sys->i_free_frame_size = p_sys->i_frame_size;
}
/* Copy the whole frame into the buffer. */
if (block_GetBytes( &p_sys->bytestream,
p_buf, __MIN( (unsigned)p_sys->i_frame_size, p_out_buffer->i_buffer ) )) {
block_Release(p_out_buffer);
return NULL;
}
#ifdef HAVE_MPGA_FILTER
/* Get beginning of next frame for libmad */
if( !p_sys->b_packetizer )
{
assert( p_out_buffer->i_buffer >= (unsigned)p_sys->i_frame_size + MAD_BUFFER_GUARD );
memcpy( p_buf + p_sys->i_frame_size,
p_header, MAD_BUFFER_GUARD );
}
#endif
p_sys->i_state = STATE_NOSYNC;
/* 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 */
p_block = block_BytestreamPop( &p_sys->bytestream );
if (pp_block)
*pp_block = p_block;
else if (p_block)
block_Release(p_block);
return p_out_buffer;
}
}
return NULL;
}
/*****************************************************************************
* 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->i_rate )
{
msg_Dbg( p_dec, "MPGA channels:%d samplerate:%d bitrate:%d",
p_sys->i_channels, p_sys->i_rate, p_sys->i_bit_rate );
date_Init( &p_sys->end_date, p_sys->i_rate, 1 );
date_Set( &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_frame_length = p_sys->i_frame_length;
p_dec->fmt_out.audio.i_bytes_per_frame =
p_sys->i_max_frame_size + MAD_BUFFER_GUARD;
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 * 1000;
#ifdef HAVE_MPGA_FILTER
if( !p_sys->b_packetizer )
{
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;
}
else
#endif
{
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;
}
return p_buf;
}
#ifdef HAVE_MPGA_FILTER
/*****************************************************************************
* GetAoutBuffer:
*****************************************************************************/
static block_t *GetAoutBuffer( decoder_t *p_dec )
{
decoder_sys_t *p_sys = p_dec->p_sys;
block_t *p_buf;
p_buf = decoder_NewAudioBuffer( p_dec, p_sys->i_frame_length );
if( p_buf == NULL ) return NULL;
p_buf->i_pts = date_Get( &p_sys->end_date );
p_buf->i_length = date_Increment( &p_sys->end_date, p_sys->i_frame_length )
- p_buf->i_pts;
if( p_sys->b_discontinuity )
p_buf->i_flags |= BLOCK_FLAG_DISCONTINUITY;
p_sys->b_discontinuity = false;
/* Hack for libmad filter */
p_buf = block_Realloc( p_buf, 0, p_sys->i_frame_size + MAD_BUFFER_GUARD );
return p_buf;
}
#endif
/*****************************************************************************
* 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_Alloc( p_sys->i_frame_size );
if( p_block == NULL ) return NULL;
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->i_frame_length ) - p_block->i_pts;
return p_block;
}
/*****************************************************************************
* Close: clean up the decoder
*****************************************************************************/
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;
block_BytestreamRelease( &p_sys->bytestream );
free( p_sys );
}
/*****************************************************************************
* SyncInfo: parse MPEG audio sync info
*****************************************************************************/
static int SyncInfo( uint32_t i_header, unsigned int * pi_channels,
unsigned int * pi_channels_conf,
unsigned int * pi_sample_rate, unsigned int * pi_bit_rate,
unsigned int * pi_frame_length,
unsigned int * pi_max_frame_size, unsigned int * pi_layer)
{
static const int ppi_bitrate[2][3][16] =
{
{
/* v1 l1 */
{ 0, 32, 64, 96, 128, 160, 192, 224, 256, 288, 320, 352, 384,
416, 448, 0},
/* v1 l2 */
{ 0, 32, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256,
320, 384, 0},
/* v1 l3 */
{ 0, 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224,
256, 320, 0}
},
{
/* v2 l1 */
{ 0, 32, 48, 56, 64, 80, 96, 112, 128, 144, 160, 176, 192,
224, 256, 0},
/* v2 l2 */
{ 0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128,
144, 160, 0},
/* v2 l3 */
{ 0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128,
144, 160, 0}
}
};
static const int ppi_samplerate[2][4] = /* version 1 then 2 */
{
{ 44100, 48000, 32000, 0 },
{ 22050, 24000, 16000, 0 }
};
int i_version, i_mode, i_emphasis;
bool b_padding, b_mpeg_2_5;
int i_frame_size = 0;
int i_bitrate_index, i_samplerate_index;
int i_max_bit_rate;
b_mpeg_2_5 = 1 - ((i_header & 0x100000) >> 20);
i_version = 1 - ((i_header & 0x80000) >> 19);
*pi_layer = 4 - ((i_header & 0x60000) >> 17);
//bool b_crc = !((i_header >> 16) & 0x01);
i_bitrate_index = (i_header & 0xf000) >> 12;
i_samplerate_index = (i_header & 0xc00) >> 10;
b_padding = (i_header & 0x200) >> 9;
/* Extension */
i_mode = (i_header & 0xc0) >> 6;
/* Modeext, copyright & original */
i_emphasis = i_header & 0x3;
if( *pi_layer != 4 &&
i_bitrate_index < 0x0f &&
i_samplerate_index != 0x03 &&
i_emphasis != 0x02 )
{
switch ( i_mode )
{
case 0: /* stereo */
case 1: /* joint stereo */
*pi_channels = 2;
*pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
break;
case 2: /* dual-mono */
*pi_channels = 2;
*pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
| AOUT_CHAN_DUALMONO;
break;
case 3: /* mono */
*pi_channels = 1;
*pi_channels_conf = AOUT_CHAN_CENTER;
break;
}
*pi_bit_rate = ppi_bitrate[i_version][*pi_layer-1][i_bitrate_index];
i_max_bit_rate = ppi_bitrate[i_version][*pi_layer-1][14];
*pi_sample_rate = ppi_samplerate[i_version][i_samplerate_index];
if ( b_mpeg_2_5 )
{
*pi_sample_rate >>= 1;
}
switch( *pi_layer )
{
case 1:
i_frame_size = ( 12000 * *pi_bit_rate / *pi_sample_rate +
b_padding ) * 4;
*pi_max_frame_size = ( 12000 * i_max_bit_rate /
*pi_sample_rate + 1 ) * 4;
*pi_frame_length = 384;
break;
case 2:
i_frame_size = 144000 * *pi_bit_rate / *pi_sample_rate + b_padding;
*pi_max_frame_size = 144000 * i_max_bit_rate / *pi_sample_rate + 1;
*pi_frame_length = 1152;
break;
case 3:
i_frame_size = ( i_version ? 72000 : 144000 ) *
*pi_bit_rate / *pi_sample_rate + b_padding;
*pi_max_frame_size = ( i_version ? 72000 : 144000 ) *
i_max_bit_rate / *pi_sample_rate + 1;
*pi_frame_length = i_version ? 576 : 1152;
break;
default:
break;
}
/* Free bitrate mode can support higher bitrates */
if( !*pi_bit_rate ) *pi_max_frame_size *= 2;
}
else
{
return -1;
}
return i_frame_size;
}