videolan
/
vlc
mirror of https://code.videolan.org/videolan/vlc
1
Fork 0
Code Releases Activity
vlc/modules/packetizer/mpeg4audio.c

496 lines
17 KiB
C
Raw Blame History

/*****************************************************************************
* mpeg4audio.c: parse and packetize an MPEG 4 audio stream
*****************************************************************************
* Copyright (C) 2001, 2002 VideoLAN
* $Id: mpeg4audio.c,v 1.17 2004/02/25 18:43:24 gbazin Exp $
*
* Authors: Laurent Aimar <fenrir@via.ecp.fr>
* Gildas Bazin <gbazin@netcourrier.com>
*
* 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., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
*****************************************************************************/
/*****************************************************************************
* Preamble
*****************************************************************************/
#include <stdlib.h> /* malloc(), free() */
#include <string.h> /* strdup() */
#include <vlc/vlc.h>
#include <vlc/aout.h>
#include <vlc/decoder.h>
#include <vlc/input.h>
#include <vlc/sout.h>
#include "codecs.h"
#include "vlc_block_helper.h"
/* AAC Config in ES:
*
* AudioObjectType 5 bits
* samplingFrequencyIndex 4 bits
* if (samplingFrequencyIndex == 0xF)
* samplingFrequency 24 bits
* channelConfiguration 4 bits
* GA_SpecificConfig
* FrameLengthFlag 1 bit 1024 or 960
* DependsOnCoreCoder 1 bit (always 0)
* ExtensionFlag 1 bit (always 0)
*/
/*****************************************************************************
* decoder_sys_t : decoder descriptor
*****************************************************************************/
struct decoder_sys_t
{
/*
* 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_raw_blocks;
unsigned int i_channels;
unsigned int i_rate, i_frame_length, i_header_size;
};
enum {
STATE_NOSYNC,
STATE_SYNC,
STATE_HEADER,
STATE_NEXT_SYNC,
STATE_GET_DATA,
STATE_SEND_DATA
};
static int i_sample_rates[] =
{
96000, 88200, 64000, 48000, 44100, 32000, 24000, 22050,
16000, 12000, 11025, 8000, 7350, 0, 0, 0
};
#define ADTS_HEADER_SIZE 9
/****************************************************************************
* Local prototypes
****************************************************************************/
static int OpenPacketizer( vlc_object_t * );
static void ClosePacketizer( vlc_object_t * );
static block_t *PacketizeBlock ( decoder_t *, block_t ** );
static block_t *ADTSPacketizeBlock( decoder_t *, block_t ** );
static uint8_t *GetOutBuffer ( decoder_t *, void ** );
static int ADTSSyncInfo( decoder_t *, const byte_t * p_buf,
unsigned int * pi_channels,
unsigned int * pi_sample_rate,
unsigned int * pi_frame_length,
unsigned int * pi_header_size,
unsigned int * pi_raw_blocks );
/*****************************************************************************
* Module descriptor
*****************************************************************************/
vlc_module_begin();
set_description( _("MPEG4 audio packetizer") );
set_capability( "packetizer", 50 );
set_callbacks( OpenPacketizer, ClosePacketizer );
vlc_module_end();
/*****************************************************************************
* OpenPacketizer: probe the packetizer and return score
*****************************************************************************/
static int OpenPacketizer( 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( 'm', 'p', '4', 'a' ) )
{
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 )
{
msg_Err( p_dec, "out of memory" );
return VLC_EGENERIC;
}
/* Misc init */
p_sys->i_state = STATE_NOSYNC;
aout_DateSet( &p_sys->end_date, 0 );
p_sys->bytestream = block_BytestreamInit( p_dec );
/* Set output properties */
p_dec->fmt_out.i_cat = AUDIO_ES;
p_dec->fmt_out.i_codec = VLC_FOURCC('m','p','4','a');
/* Set callback */
p_dec->pf_packetize = PacketizeBlock;
msg_Info( p_dec, "running MPEG4 audio packetizer" );
if( p_dec->fmt_in.i_extra > 0 )
{
uint8_t *p_config = (uint8_t*)p_dec->fmt_in.p_extra;
int i_index;
i_index = ( ( p_config[0] << 1 ) | ( p_config[1] >> 7 ) ) & 0x0f;
if( i_index != 0x0f )
{
p_dec->fmt_out.audio.i_rate = i_sample_rates[i_index];
p_dec->fmt_out.audio.i_frame_length =
(( p_config[1] >> 2 ) & 0x01) ? 960 : 1024;
}
else
{
p_dec->fmt_out.audio.i_rate = ( ( p_config[1] & 0x7f ) << 17 ) |
( p_config[2] << 9 ) | ( p_config[3] << 1 ) |
( p_config[4] >> 7 );
p_dec->fmt_out.audio.i_frame_length =
(( p_config[4] >> 2 ) & 0x01) ? 960 : 1024;
}
msg_Dbg( p_dec, "AAC %dHz %d samples/frame",
p_dec->fmt_out.audio.i_rate,
p_dec->fmt_out.audio.i_frame_length );
aout_DateInit( &p_sys->end_date, p_dec->fmt_out.audio.i_rate );
p_dec->fmt_out.audio.i_channels = p_dec->fmt_in.audio.i_channels;
p_dec->fmt_out.i_extra = p_dec->fmt_in.i_extra;
p_dec->fmt_out.p_extra = malloc( p_dec->fmt_in.i_extra );
memcpy( p_dec->fmt_out.p_extra, p_dec->fmt_in.p_extra,
p_dec->fmt_in.i_extra );
}
else
{
msg_Dbg( p_dec, "no decoder specific info, must be an ADTS stream" );
/* We will try to create a AAC Config from adts */
p_dec->fmt_out.i_extra = 0;
p_dec->fmt_out.p_extra = NULL;
p_dec->pf_packetize = ADTSPacketizeBlock;
}
return VLC_SUCCESS;
}
/****************************************************************************
* PacketizeBlock: the whole thing
****************************************************************************
* This function must be fed with complete frames.
****************************************************************************/
static block_t *PacketizeBlock( decoder_t *p_dec, block_t **pp_block )
{
decoder_sys_t *p_sys = p_dec->p_sys;
block_t *p_block;
if( !pp_block || !*pp_block ) return NULL;
p_block = *pp_block;
*pp_block = NULL; /* Don't reuse this block */
if( !aout_DateGet( &p_sys->end_date ) && !p_block->i_pts )
{
/* We've just started the stream, wait for the first PTS. */
block_Release( p_block );
return NULL;
}
else if( p_block->i_pts != 0 &&
p_block->i_pts != aout_DateGet( &p_sys->end_date ) )
{
aout_DateSet( &p_sys->end_date, p_block->i_pts );
}
p_block->i_pts = p_block->i_dts = aout_DateGet( &p_sys->end_date );
p_block->i_length = aout_DateIncrement( &p_sys->end_date,
p_dec->fmt_out.audio.i_frame_length ) - p_block->i_pts;
return p_block;
}
/****************************************************************************
* DTSPacketizeBlock: the whole thing
****************************************************************************/
static block_t *ADTSPacketizeBlock( decoder_t *p_dec, block_t **pp_block )
{
decoder_sys_t *p_sys = p_dec->p_sys;
uint8_t p_header[ADTS_HEADER_SIZE];
void *p_out_buffer;
uint8_t *p_buf;
if( !pp_block || !*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_flags&BLOCK_FLAG_DISCONTINUITY )
{
p_sys->i_state = STATE_NOSYNC;
}
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 )
{
/* Look for sync word - should be 0xfff + 2 layer bits */
if( p_header[0] == 0xff && (p_header[1] & 0xf6) == 0xf0 )
{
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;
break;
case STATE_HEADER:
/* Get ADTS frame header (ADTS_HEADER_SIZE bytes) */
if( block_PeekBytes( &p_sys->bytestream, p_header,
ADTS_HEADER_SIZE ) != VLC_SUCCESS )
{
/* Need more data */
return NULL;
}
/* Check if frame is valid and get frame info */
p_sys->i_frame_size = ADTSSyncInfo( p_dec, p_header,
&p_sys->i_channels,
&p_sys->i_rate,
&p_sys->i_frame_length,
&p_sys->i_header_size,
&p_sys->i_raw_blocks );
if( p_sys->i_frame_size <= 0 )
{
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 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_sys->i_header_size, p_header, 2 )
!= VLC_SUCCESS )
{
/* Need more data */
return NULL;
}
if( p_header[0] != 0xff || (p_header[1] & 0xf6) != 0xf0 )
{
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 +
p_sys->i_header_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 = VLC_TRUE;
return NULL;
}
/* When we reach this point we already know we have enough
* data available. */
/* Skip the ADTS header */
block_SkipBytes( &p_sys->bytestream, p_sys->i_header_size );
/* Copy the whole frame into the buffer */
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;
}
/*****************************************************************************
* GetOutBuffer:
*****************************************************************************/
static uint8_t *GetOutBuffer( decoder_t *p_dec, void **pp_out_buffer )
{
decoder_sys_t *p_sys = p_dec->p_sys;
block_t *p_block;
if( p_dec->fmt_out.audio.i_rate != p_sys->i_rate )
{
msg_Info( p_dec, "AAC channels: %d samplerate: %d",
p_sys->i_channels, p_sys->i_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 = p_sys->i_frame_length;
#if 0
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;
#endif
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,
p_sys->i_frame_length ) - p_block->i_pts;
*pp_out_buffer = p_block;
return p_block->p_buffer;
}
/*****************************************************************************
* ClosePacketizer: clean up the packetizer
*****************************************************************************/
static void ClosePacketizer( 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_dec->p_sys );
}
/*****************************************************************************
* ADTSSyncInfo: parse MPEG 4 audio ADTS sync info
*****************************************************************************/
static int ADTSSyncInfo( decoder_t * p_dec, const byte_t * p_buf,
unsigned int * pi_channels,
unsigned int * pi_sample_rate,
unsigned int * pi_frame_length,
unsigned int * pi_header_size,
unsigned int * pi_raw_blocks_in_frame )
{
int i_id, i_profile, i_sample_rate_idx, i_frame_size;
vlc_bool_t b_crc;
/* Fixed header between frames */
i_id = ( (p_buf[1] >> 3) & 0x01 ) ? 2 : 4;
b_crc = !(p_buf[1] & 0x01);
i_profile = p_buf[2] >> 6;
i_sample_rate_idx = (p_buf[2] >> 2) & 0x0f;
*pi_sample_rate = i_sample_rates[i_sample_rate_idx];
*pi_channels = ((p_buf[2] & 0x01) << 2) | ((p_buf[3] >> 6) & 0x03);
/* Variable header */
i_frame_size = ((p_buf[3] & 0x03) << 11) | (p_buf[4] << 3) |
((p_buf[5] >> 5) & 0x7);
*pi_raw_blocks_in_frame = (p_buf[6] & 0x02) + 1;
if( !*pi_sample_rate || !*pi_channels || !i_frame_size )
{
return 0;
}
/* Fixme */
*pi_frame_length = 1024;
/* Build the decoder specific info header */
if( !p_dec->fmt_out.i_extra )
{
p_dec->fmt_out.i_extra = 2;
p_dec->fmt_out.p_extra = malloc( 2 );
((uint8_t *)p_dec->fmt_out.p_extra)[0] =
(i_profile + 1) << 3 | (i_sample_rate_idx >> 1);
((uint8_t *)p_dec->fmt_out.p_extra)[1] =
((i_sample_rate_idx & 0x01) << 7) | (*pi_channels <<3);
}
/* ADTS header length */
*pi_header_size = b_crc ? 9 : 7;
return i_frame_size - *pi_header_size;
}
View Git Blame Copy Permalink