mpeg4audio.c

VLC Player Source Code

/*****************************************************************************
 * mpeg4audio.c: parse and packetize an MPEG 4 audio stream
 *****************************************************************************
 * Copyright (C) 2001, 2002, 2006 the VideoLAN team
 * $Id$
 *
 * Authors: Laurent Aimar <[e-mail]>
 *          Gildas Bazin <[e-mail]>
 *
 * 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_common.h>
#include <vlc_plugin.h>
#include <vlc_aout.h>
#include <vlc_codec.h>
#include <vlc_block.h>
#include <vlc_sout.h>
#include <vlc_codecs.h>
#include <vlc_input.h>
#include <vlc_bits.h>

#include "vlc_block_helper.h"

#include <assert.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
 *****************************************************************************/
typedef struct
{
    int i_object_type;
    int i_samplerate;
    int i_channel;
    int i_sbr;          // 0: no sbr, 1: sbr, -1: unknown

    struct
    {
        int i_object_type;
        int i_samplerate;
    } extension;

    /* GASpecific */
    int i_frame_length;   // 1024 or 960

} mpeg4_cfg_t;

#define LATM_MAX_EXTRA_SIZE 64
typedef struct
{
    int i_program;
    int i_layer;

    int i_frame_length_type;
    int i_frame_length;         // type 1
    int i_frame_length_index;   // type 3 4 5 6 7

    mpeg4_cfg_t cfg;

    /* Raw configuration */
    int     i_extra;
    uint8_t extra[LATM_MAX_EXTRA_SIZE];

} latm_stream_t;

#define LATM_MAX_LAYER (8)
#define LATM_MAX_PROGRAM (16)
typedef struct
{
    int b_same_time_framing;
    int i_sub_frames;
    int i_programs;

    int pi_layers[LATM_MAX_PROGRAM];

    int pi_stream[LATM_MAX_PROGRAM][LATM_MAX_LAYER];

    int i_streams;
    latm_stream_t stream[LATM_MAX_PROGRAM*LATM_MAX_LAYER];

    int i_other_data;
    int i_crc;  /* -1 if not set */
} latm_mux_t;

struct decoder_sys_t
{
    /*
     * Input properties
     */
    int i_state;
    int i_type;

    block_bytestream_t bytestream;

    /*
     * Common properties
     */
    audio_date_t end_date;
    mtime_t i_pts;

    int i_frame_size;
    unsigned int i_channels;
    unsigned int i_rate, i_frame_length, i_header_size;

    int i_input_rate;

    /* LOAS */
    bool b_latm_cfg;
    latm_mux_t latm;
};

enum {
    STATE_NOSYNC,
    STATE_SYNC,
    STATE_HEADER,
    STATE_NEXT_SYNC,
    STATE_GET_DATA,
    STATE_SEND_DATA
};

enum {
    TYPE_NONE,
    TYPE_RAW,
    TYPE_ADTS,
    TYPE_LOAS
};

static const int pi_sample_rates[16] =
{
    96000, 88200, 64000, 48000, 44100, 32000, 24000, 22050,
    16000, 12000, 11025, 8000,  7350,  0,     0,     0
};

#define ADTS_HEADER_SIZE 9
#define LOAS_HEADER_SIZE 3

/****************************************************************************
 * Local prototypes
 ****************************************************************************/
static int  OpenPacketizer( vlc_object_t * );
static void ClosePacketizer( vlc_object_t * );

static block_t *PacketizeRawBlock    ( decoder_t *, block_t ** );
static block_t *PacketizeStreamBlock( decoder_t *, block_t ** );

/*****************************************************************************
 * Module descriptor
 *****************************************************************************/
vlc_module_begin();
    set_category( CAT_SOUT );
    set_subcategory( SUBCAT_SOUT_PACKETIZER );
    set_description( N_("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 )
        return VLC_ENOMEM;

    /* Misc init */
    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;
    p_sys->b_latm_cfg = false;

    /* Set output properties */
    p_dec->fmt_out.i_cat = AUDIO_ES;
    p_dec->fmt_out.i_codec = VLC_FOURCC('m','p','4','a');

    msg_Dbg( 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 = pi_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;
        }

        p_dec->fmt_out.audio.i_channels =
            (p_config[i_index == 0x0f ? 4 : 1] >> 3) & 0x0f;

        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.i_extra = p_dec->fmt_in.i_extra;
        p_dec->fmt_out.p_extra = malloc( p_dec->fmt_in.i_extra );
        if( !p_dec->fmt_out.p_extra )
        {
            p_dec->fmt_out.i_extra = 0;
            return VLC_ENOMEM;
        }
        memcpy( p_dec->fmt_out.p_extra, p_dec->fmt_in.p_extra,
                p_dec->fmt_in.i_extra );

        /* Set callback */
        p_dec->pf_packetize = PacketizeRawBlock;
        p_sys->i_type = TYPE_RAW;
    }
    else
    {
        msg_Dbg( p_dec, "no decoder specific info, must be an ADTS or LOAS stream" );

        aout_DateInit( &p_sys->end_date, p_dec->fmt_in.audio.i_rate );

        /* We will try to create a AAC Config from adts/loas */
        p_dec->fmt_out.i_extra = 0;
        p_dec->fmt_out.p_extra = NULL;

        /* Set callback */
        p_dec->pf_packetize = PacketizeStreamBlock;
        p_sys->i_type = TYPE_NONE;
    }

    return VLC_SUCCESS;
}

/****************************************************************************
 * PacketizeRawBlock: the whole thing
 ****************************************************************************
 * This function must be fed with complete frames.
 ****************************************************************************/
static block_t *PacketizeRawBlock( 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;

    if( (*pp_block)->i_flags&(BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
    {
        //aout_DateSet( &p_sys->end_date, 0 );
        block_Release( *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_sys->i_input_rate / INPUT_RATE_DEFAULT ) - p_block->i_pts;

    return p_block;
}

/****************************************************************************
 * ADTS helpers
 ****************************************************************************/
static int ADTSSyncInfo( decoder_t * p_dec, const uint8_t * p_buf,
                         unsigned int * pi_channels,
                         unsigned int * pi_sample_rate,
                         unsigned int * pi_frame_length,
                         unsigned int * pi_header_size )
{
    int i_profile, i_sample_rate_idx, i_frame_size;
    bool b_crc;

    /* Fixed header between frames */
    //int i_id = ( (p_buf[1] >> 3) & 0x01) ? 2 : 4; /* MPEG-2 or 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 = pi_sample_rates[i_sample_rate_idx];
    //private_bit = (p_buf[2] >> 1) & 0x01;
    *pi_channels = ((p_buf[2] & 0x01) << 2) | ((p_buf[3] >> 6) & 0x03);
    //original_copy = (p_buf[3] >> 5) & 0x01;
    //home = (p_buf[3] >> 4) & 0x01;

    /* Variable header */
    //copyright_id_bit = (p_buf[3] >> 3) & 0x01;
    //copyright_id_start = (p_buf[3] >> 2) & 0x01;
    i_frame_size = ((p_buf[3] & 0x03) << 11) | (p_buf[4] << 3) |
                   ((p_buf[5] >> 5) /*& 0x7*/);
    //uint16_t buffer_fullness = ((p_buf[5] & 0x1f) << 6) | (p_buf[6] >> 2);
    unsigned short i_raw_blocks_in_frame = p_buf[6] & 0x03;

    if( !*pi_sample_rate || !*pi_channels || !i_frame_size )
    {
        msg_Warn( p_dec, "Invalid ADTS header" );
        return 0;
    }

    *pi_frame_length = 1024;

    if( i_raw_blocks_in_frame == 0 )
    {
        if( b_crc )
        {
            msg_Warn( p_dec, "ADTS CRC not supported" );
            //uint16_t crc = (p_buf[7] << 8) | p_buf[8];
        }
    }
    else
    {
        msg_Err( p_dec, "Multiple blocks per frame in ADTS not supported" );
        return 0;
#if 0
        int i;
        const uint8_t *p_pos = p_buf + 7;
        uint16_t crc_block;
        uint16_t i_block_pos[3];
        if( b_crc )
        {
            for( i = 0 ; i < i_raw_blocks_in_frame ; i++ )
            {   /* the 1st block's position is known ... */
                i_block_pos[i] = (*p_pos << 8) | *(p_pos+1);
                p_pos += 2;
            }
            crc_block = (*p_pos << 8) | *(p_pos+1);
            p_pos += 2;
        }
        for( i = 0 ; i <= i_raw_blocks_in_frame ; i++ )
        {
            //read 1 block
            if( b_crc )
            {
                msg_Err( p_dec, "ADTS CRC not supported" );
                //uint16_t crc = (*p_pos << 8) | *(p_pos+1);
                //p_pos += 2;
            }
        }
#endif
    }


    /* Build the decoder specific info header */
    if( !p_dec->fmt_out.i_extra )
    {
        p_dec->fmt_out.p_extra = malloc( 2 );
        if( !p_dec->fmt_out.p_extra )
        {
            p_dec->fmt_out.i_extra = 0;
            return 0;