/*****************************************************************************

 * mlp.c: packetize MLP/TrueHD audio

 *****************************************************************************

 * Copyright (C) 2008 Laurent Aimar

 *

 * Authors: Laurent Aimar < fenrir _AT videolan _DOT_ 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_bits.h>

#include <assert.h>

#include "packetizer_helper.h"

#include "a52.h"

/*****************************************************************************

 * Module descriptor

 *****************************************************************************/

static int  Open ( vlc_object_t * );

static void Close( vlc_object_t * );

vlc_module_begin ()

    set_subcategory( SUBCAT_SOUT_PACKETIZER )

    set_description( N_("MLP/TrueHD parser") )

    set_capability( "audio packetizer", 50 )

    set_callbacks( Open, Close )

vlc_module_end ()

/*****************************************************************************

 *

 *****************************************************************************/

typedef struct

{

    int i_type;

    unsigned i_rate;

    unsigned i_channels;

    int i_channels_conf;

    unsigned i_samples;

    bool b_vbr;

    unsigned  i_bitrate;

    unsigned  i_substreams;

} mlp_header_t;

typedef struct

{

    /*

     * Input properties

     */

    int i_state;

    block_bytestream_t bytestream;

    /*

     * Common properties

     */

    date_t  end_date;

    bool    b_discontinuity;

    vlc_tick_t i_pts;

    int i_frame_size;

    bool         b_mlp;

    mlp_header_t mlp;

} decoder_sys_t;

#define MLP_MAX_SUBSTREAMS (16)

#define MLP_HEADER_SYNC (28)

#define MLP_HEADER_SIZE (4 + MLP_HEADER_SYNC + 4 * MLP_MAX_SUBSTREAMS)

static const uint8_t pu_start_code[3] = { 0xf8, 0x72, 0x6f };

/**

 * It parse MLP sync info.

 *

 * TODO handle CRC (at offset 26)

 */

static int TrueHdChannels( int i_map )

{

    static const uint8_t pu_thd[13] =

    {

         2, 1, 1, 2, 2, 2, 2, 1, 1, 2, 2, 1, 1

    };

    int i_count = 0;

    for( int i = 0; i < 13; i++ )

    {

        if( i_map & (1<<i) )

            i_count += pu_thd[i];

    }

    return i_count;

}

static int MlpParse( mlp_header_t *p_mlp, const uint8_t p_hdr[MLP_HEADER_SYNC] )

{

    bs_t s;

    assert( !memcmp( p_hdr, pu_start_code, 3 ) );

    /* TODO Checksum ? */

    /* */

    bs_init( &s, &p_hdr[3], MLP_HEADER_SYNC - 3 );

    /* Stream type */

    p_mlp->i_type = bs_read( &s, 8 );

    int i_rate_idx1;

    if( p_mlp->i_type == 0xbb )        /* MLP */

    {

        static const unsigned pu_channels[32] = {

            1, 2, 3, 4, 3, 4, 5, 3, 4, 5, 4, 5, 6, 4, 5, 4,

            5, 6, 5, 5, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

        };

        bs_skip( &s, 4 + 4 );

        i_rate_idx1 = bs_read( &s, 4 );

        // Just skip the 4 following, since we don't use it

        // const int i_rate_idx2 = bs_read( &s, 4 );

        bs_skip( &s, 4 );

        bs_skip( &s, 11 );

        const int i_channel_idx = bs_read( &s, 5 );

        p_mlp->i_channels = pu_channels[i_channel_idx];

    }

    else if( p_mlp->i_type == 0xba )   /* True HD */

    {

        i_rate_idx1 = bs_read( &s, 4 );

        bs_skip( &s, 8 );

        const int i_channel1 = bs_read( &s, 5 );

        bs_skip( &s, 2 );

        const int i_channel2 = bs_read( &s, 13 );

        if( i_channel2 )

            p_mlp->i_channels = TrueHdChannels( i_channel2 );

        else

            p_mlp->i_channels = TrueHdChannels( i_channel1 );

    }

    else

    {

        return VLC_EGENERIC;

    }

    if( i_rate_idx1 == 0x0f )

        p_mlp->i_rate = 0;

    else

        p_mlp->i_rate = ( ( i_rate_idx1 & 0x8 ) ? 44100 : 48000 ) << (i_rate_idx1 & 0x7);

    p_mlp->i_channels_conf = 0; /* TODO ? */

    p_mlp->i_samples = 40 << ( i_rate_idx1 & 0x07 );

    bs_skip( &s, 48 );

    p_mlp->b_vbr = bs_read( &s, 1 );

    p_mlp->i_bitrate = ( bs_read( &s, 15 ) * p_mlp->i_rate + 8) / 16;

    p_mlp->i_substreams = bs_read( &s, 4 );

    bs_skip( &s, 4 + 11 * 8 );

    //fprintf( stderr, "i_samples = %d channels:%d rate:%d bitsrate=%d substreams=%d\n",

    //        p_mlp->i_samples, p_mlp->i_channels, p_mlp->i_rate, p_mlp->i_bitrate, p_mlp->i_substreams );

    return VLC_SUCCESS;

}

static int SyncInfo( const uint8_t *p_hdr, bool *pb_mlp, mlp_header_t *p_mlp )

{

    /* Check major sync presence */

    const bool b_has_sync = !memcmp( &p_hdr[4], pu_start_code, 3 );

    /* Wait for a major sync */

    if( !b_has_sync && !*pb_mlp )

        return 0;

    /* Parse major sync if present */

    if( b_has_sync )

    {

        *pb_mlp = !MlpParse( p_mlp, &p_hdr[4] );

        if( !*pb_mlp )

            return 0;

    }

    if( !b_has_sync )

    {

        int i_tmp = 0 ^ p_hdr[0] ^ p_hdr[1] ^ p_hdr[2] ^ p_hdr[3];

        const uint8_t *p = &p_hdr[4];

        for( unsigned i = 0; i < p_mlp->i_substreams; i++ )

        {

            i_tmp ^= *p++;

            i_tmp ^= *p++;

            if( p[-2] & 0x80 )

            {

                i_tmp ^= *p++;

                i_tmp ^= *p++;

            }

        }

        i_tmp = ( i_tmp >> 4 ) ^ i_tmp;

        if( ( i_tmp & 0x0f ) != 0x0f )

            return 0;

    }

    /* */

    const int i_word = ( ( p_hdr[0] << 8 ) | p_hdr[1] ) & 0xfff;

    return i_word * 2;

}

/**

 * It returns the size of an AC3/EAC3 frame (or 0 if invalid)

 */

static int SyncInfoDolby( const uint8_t *p_buf )

{

    vlc_a52_header_t a52;

    if( vlc_a52_header_Parse( &a52, p_buf, MLP_HEADER_SIZE ) == VLC_SUCCESS )

        return a52.i_size;

    else

        return 0;

}

static void Flush( decoder_t *p_dec )

{

    decoder_sys_t *p_sys = p_dec->p_sys;

    p_sys->b_mlp = false;

    p_sys->i_state = STATE_NOSYNC;

    p_sys->b_discontinuity = true;

    block_BytestreamEmpty( &p_sys->bytestream );

    date_Set( &p_sys->end_date, VLC_TICK_INVALID );

}

static block_t *Packetize( decoder_t *p_dec, block_t **pp_block )

{

    decoder_sys_t *p_sys = p_dec->p_sys;

    uint8_t p_header[MLP_HEADER_SIZE];

    block_t *p_out_buffer;

    block_t *p_block = pp_block ? *pp_block : NULL;

    if ( p_block )

    {

        if( p_block->i_flags & (BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )

        {

            /* First always drain complete blocks before discontinuity */

            block_t *p_drain = Packetize( p_dec, NULL );

            if( p_drain )

                return p_drain;

            Flush( p_dec );

            if( p_block->i_flags & BLOCK_FLAG_CORRUPTED )

            {

                block_Release( p_block );

                return NULL;

            }

        }

        if( p_block->i_pts == VLC_TICK_INVALID &&

            date_Get( &p_sys->end_date ) == VLC_TICK_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 );

    }

    for( ;; )

    {

        switch( p_sys->i_state )

        {

        case STATE_NOSYNC:

            while( !block_PeekBytes( &p_sys->bytestream, p_header, MLP_HEADER_SIZE ) )

            {

                if( SyncInfo( p_header, &p_sys->b_mlp, &p_sys->mlp ) > 0 )

                {

                    p_sys->i_state = STATE_SYNC;

                    break;

                }

                else if( SyncInfoDolby( p_header ) > 0 )

                {

                    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;

            }

            /* fallthrough */

        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_TICK_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;

            /* fallthrough */

        case STATE_HEADER:

            /* Get a MLP header */

            if( block_PeekBytes( &p_sys->bytestream, p_header, MLP_HEADER_SIZE ) )

            {

                /* Need more data */

                return NULL;

            }

            /* Check if frame is valid and get frame info */

            p_sys->i_frame_size = SyncInfoDolby( p_header );

            if( p_sys->i_frame_size <= 0 )

                p_sys->i_frame_size = SyncInfo( p_header, &p_sys->b_mlp, &p_sys->mlp );

            if( p_sys->i_frame_size <= 0 )

            {

                msg_Dbg( p_dec, "emulated sync word" );

                block_SkipByte( &p_sys->bytestream );

                p_sys->b_mlp = false;

                p_sys->i_state = STATE_NOSYNC;

                break;

            }

            p_sys->i_state = STATE_NEXT_SYNC;

            /* fallthrough */

        case STATE_NEXT_SYNC:

            /* Check if next expected frame contains the sync word */

            if( block_PeekOffsetBytes( &p_sys->bytestream,

                                       p_sys->i_frame_size, p_header, MLP_HEADER_SIZE ) )

            {

                if( p_block == NULL ) /* drain */

                {

                    p_sys->i_state = STATE_GET_DATA;

                    break;

                }

                /* Need more data */

                return NULL;

            }

            bool b_mlp = p_sys->b_mlp;

            mlp_header_t mlp = p_sys->mlp;

            if( SyncInfo( p_header, &b_mlp, &mlp ) <= 0 && SyncInfoDolby( p_header ) <= 0 )

            {

                msg_Dbg( p_dec, "emulated sync word "

                         "(no sync on following frame)" );

                p_sys->b_mlp = false;

                p_sys->i_state = STATE_NOSYNC;

                block_SkipByte( &p_sys->bytestream );

                break;

            }

            p_sys->i_state = STATE_GET_DATA;

            break;

        case STATE_GET_DATA:

            /* Make sure we have enough data. */

            if( block_WaitBytes( &p_sys->bytestream, p_sys->i_frame_size ) )

            {

                /* Need more data */

                return NULL;

            }

            p_sys->i_state = STATE_SEND_DATA;

            /* fallthrough */

        case STATE_SEND_DATA:

            /* When we reach this point we already know we have enough

             * data available. */

            p_out_buffer = block_Alloc( p_sys->i_frame_size );

            if( !p_out_buffer )

                return NULL;

            /* Copy the whole frame into the buffer */

            block_GetBytes( &p_sys->bytestream,

                            p_out_buffer->p_buffer, p_out_buffer->i_buffer );

            /* Just ignore (E)AC3 frames */

            if( SyncInfoDolby( p_out_buffer->p_buffer ) > 0 )

            {

                block_Release( p_out_buffer );

                p_sys->i_state = STATE_NOSYNC;

                break;

            }

            /* Setup output */

            if( p_dec->fmt_out.audio.i_rate != p_sys->mlp.i_rate )

            {

                msg_Info( p_dec, "MLP channels: %d samplerate: %d",

                          p_sys->mlp.i_channels, p_sys->mlp.i_rate );

                if( p_sys->mlp.i_rate > 0 )

                    date_Change( &p_sys->end_date, p_sys->mlp.i_rate, 1 );

            }

            p_dec->fmt_out.audio.i_rate     = p_sys->mlp.i_rate;

            p_dec->fmt_out.audio.i_channels = p_sys->mlp.i_channels;

            p_dec->fmt_out.audio.i_physical_channels = p_sys->mlp.i_channels_conf;

            p_dec->fmt_out.audio.i_bytes_per_frame = p_sys->i_frame_size;

            p_dec->fmt_out.audio.i_frame_length = p_sys->mlp.i_samples;

            p_out_buffer->i_pts = p_out_buffer->i_dts = date_Get( &p_sys->end_date );

            p_out_buffer->i_nb_samples = p_sys->mlp.i_samples;

            p_out_buffer->i_length =

                date_Increment( &p_sys->end_date, p_sys->mlp.i_samples ) - p_out_buffer->i_pts;

            /* 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_TICK_INVALID;

            if( p_sys->b_discontinuity )

            {

                p_out_buffer->i_flags |= BLOCK_FLAG_DISCONTINUITY;

                p_sys->b_discontinuity = false;

            }

            /* So p_block doesn't get re-added several times */

            if( pp_block )

                *pp_block = block_BytestreamPop( &p_sys->bytestream );

            p_sys->i_state = STATE_NOSYNC;

            return p_out_buffer;

        }

    }

    return NULL;

}

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_MLP &&

        p_dec->fmt_in->i_codec != VLC_CODEC_TRUEHD )

        return VLC_EGENERIC;

    /* */

    p_dec->p_sys = p_sys = malloc( sizeof(*p_sys) );

    if( !p_sys )

        return VLC_ENOMEM;

    /* */

    p_sys->i_state = STATE_NOSYNC;

    date_Init( &p_sys->end_date, 1, 1 );

    block_BytestreamInit( &p_sys->bytestream );

    p_sys->b_mlp = false;

    p_sys->b_discontinuity = false;

    /* Set output properties (Passthrough only) */

    p_dec->fmt_out.i_codec = p_dec->fmt_in->i_codec;

    p_dec->fmt_out.audio.i_rate = 0;

    /* Set callback */

    p_dec->pf_packetize = Packetize;

    p_dec->pf_flush     = Flush;

    p_dec->pf_get_cc    = NULL;

    return VLC_SUCCESS;

}

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 );

}