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

 * mjpeg.c: MPEG packetizer

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

 * Copyright (C) 2018 VideoLabs, VLC authors and VideoLAN

 *

 * 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_block.h>

#include <vlc_codec.h>

#include <vlc_block_helper.h>

#include "packetizer_helper.h"

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

 * Local prototypes

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

typedef struct

{

    packetizer_t packetizer;

    int i_next_block_flags;

    date_t date;

} decoder_sys_t;

static const uint8_t p_mjpg_startcode[4] = { 0xFF, 0xD8, 0xFF, 0xE0 };

static inline const uint8_t * startcode_Find( const uint8_t *p, const uint8_t *end )

{

    while( p + 3 < end )

    {

        p = memchr( p, 0xFF, end - p );

        if( !p || end - p < 4 )

            break;

        if( p[1] == 0xD8 && p[2] == 0xFF && (p[3] & 0xE0) == 0xE0 )

            return p;

        p++;

    }

    return NULL;

}

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

 * Packetize:

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

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

{

    decoder_sys_t *p_sys = p_dec->p_sys;

    return packetizer_Packetize( &p_sys->packetizer, pp_block );

}

static void PacketizeFlush( decoder_t *p_dec )

{

    decoder_sys_t *p_sys = p_dec->p_sys;

    date_Set( &p_sys->date, VLC_TICK_INVALID );

    p_sys->i_next_block_flags = BLOCK_FLAG_DISCONTINUITY;

    packetizer_Flush( &p_sys->packetizer );

}

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

 * Helpers:

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

static void PacketizeReset( void *p_private, bool b_flush )

{

    VLC_UNUSED(b_flush);

    decoder_t *p_dec = p_private;

    decoder_sys_t *p_sys = p_dec->p_sys;

    date_Set( &p_sys->date, VLC_TICK_INVALID );

    p_sys->i_next_block_flags = BLOCK_FLAG_DISCONTINUITY;

}

static block_t *PacketizeParse( void *p_private, bool *pb_ts_used, block_t *p_block )

{

    decoder_t *p_dec = p_private;

    decoder_sys_t *p_sys = p_dec->p_sys;

    const uint8_t *p_buf = &p_block->p_buffer[2];

    size_t i_buf = p_block->i_buffer - 2;

    while( i_buf > 4 && p_buf[0] == 0xFF )

    {

        size_t i_size = 2 + GetWBE( &p_buf[2] );

        if( i_size > i_buf )

            break;

        if( p_buf[1] == 0xC0 && i_buf > 9 )

        {

            uint16_t i_height = GetWBE( &p_buf[5] );

            uint16_t i_width = GetWBE( &p_buf[7] );

            if( i_height && i_width &&

                (p_dec->fmt_out.video.i_height != i_height ||

                 p_dec->fmt_out.video.i_width != i_width) )

            {

                p_dec->fmt_out.video.i_width =

                p_dec->fmt_out.video.i_visible_width = i_width;

                p_dec->fmt_out.video.i_height =

                p_dec->fmt_out.video.i_visible_height = i_height;

            }

            break;

        }

        i_buf -= i_size;

        p_buf += i_size;

    }

    if( p_block->i_dts == VLC_TICK_INVALID )

        p_block->i_dts = p_block->i_pts;

    else if( p_block->i_pts == VLC_TICK_INVALID )

        p_block->i_pts = p_block->i_dts;

    vlc_tick_t i_prev_dts = date_Get( &p_sys->date );

    if( p_block->i_dts != VLC_TICK_INVALID )

    {

        date_Set( &p_sys->date, p_block->i_dts );

    }

    else if( p_dec->fmt_in->video.i_frame_rate &&

             p_dec->fmt_in->video.i_frame_rate_base )

    {

        date_Increment( &p_sys->date, 1 );

        p_block->i_dts = p_block->i_pts = date_Get( &p_sys->date );

    }

    if( i_prev_dts != VLC_TICK_INVALID && p_block->i_dts != VLC_TICK_INVALID )

        p_block->i_length = p_block->i_dts - i_prev_dts;

    *pb_ts_used = true;

    p_block->i_flags = p_sys->i_next_block_flags | BLOCK_FLAG_TYPE_I;

    p_sys->i_next_block_flags = 0;

    return p_block;

}

static int PacketizeValidate( void *p_private, block_t *p_au )

{

    VLC_UNUSED(p_private);

    VLC_UNUSED(p_au);

    return VLC_SUCCESS;

}

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

 * Close:

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

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;

    packetizer_Clean( &p_sys->packetizer );

    free( p_sys );

}

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

 * Open:

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

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_MJPG )

        return VLC_EGENERIC;

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

    if( !p_dec->p_sys )

        return VLC_ENOMEM;

    p_sys->i_next_block_flags = 0;

    if( p_dec->fmt_in->video.i_frame_rate &&

        p_dec->fmt_in->video.i_frame_rate_base )

    {

        date_Init( &p_sys->date, p_dec->fmt_in->video.i_frame_rate,

                   p_dec->fmt_in->video.i_frame_rate_base );

    }

    else

        date_Init( &p_sys->date, 30000, 1001 );

    es_format_Copy( &p_dec->fmt_out, p_dec->fmt_in );

    /* Misc init */

    packetizer_Init( &p_sys->packetizer,

                     p_mjpg_startcode, sizeof(p_mjpg_startcode), startcode_Find,

                     NULL, 0, 295,

                     PacketizeReset, PacketizeParse, PacketizeValidate, NULL,

                     p_dec );

    p_dec->pf_packetize = Packetize;

    p_dec->pf_flush = PacketizeFlush;

    p_dec->pf_get_cc = NULL;

    return VLC_SUCCESS;

}

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

 * Module descriptor

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

vlc_module_begin ()

    set_subcategory( SUBCAT_SOUT_PACKETIZER )

    set_description( N_("MJPEG video packetizer") )

    set_capability( "video packetizer", 50 )

    set_callbacks( Open, Close )

vlc_module_end ()