system.c

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/*****************************************************************************
 * system.c: helper module for TS, PS and PES management
 *****************************************************************************
 * Copyright (C) 1998-2004 VideoLAN
 * $Id: system.c,v 1.31 2004/02/20 17:16:50 massiot Exp $
 *
 * Authors: Christophe Massiot <[e-mail]>
 *          Michel Lespinasse <[e-mail]>
 *          Beno顃 Steiner <[e-mail]>
 *          Sam Hocevar <[e-mail]>
 *          Henri Fallon <[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., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
 *****************************************************************************/

/*****************************************************************************
 * Preamble
 *****************************************************************************/
#include <stdlib.h>

#include <vlc/vlc.h>
#include <vlc/input.h>

#include "system.h"

/*****************************************************************************
 * Local prototypes
 *****************************************************************************/
static int  Activate   ( vlc_object_t * );

static ssize_t           ReadPS  ( input_thread_t *, data_packet_t ** );
static es_descriptor_t * ParsePS ( input_thread_t *, data_packet_t * );
static void              DemuxPS ( input_thread_t *, data_packet_t * );

static ssize_t           ReadTS  ( input_thread_t *, data_packet_t ** );
static void              DemuxTS ( input_thread_t *, data_packet_t *,
                                   psi_callback_t );

/*****************************************************************************
 * Module descriptor
 *****************************************************************************/
vlc_module_begin();
    set_description( _("Generic ISO 13818-1 MPEG demultiplexing") );
    set_capability( "mpeg-system", 100 );
    set_callbacks( Activate, NULL );
vlc_module_end();

/*****************************************************************************
 * Activate: initializes helper functions
 *****************************************************************************/
static int Activate ( vlc_object_t *p_this )
{
    static mpeg_demux_t mpeg_demux =
                    { NULL, ReadPS, ParsePS, DemuxPS, ReadTS, DemuxTS };
    mpeg_demux.cur_scr_time = -1;
    memcpy( p_this->p_private, &mpeg_demux, sizeof( mpeg_demux ) );

    return VLC_SUCCESS;
}

/*
 * PES Packet management
 */

/*****************************************************************************
 * MoveChunk
 *****************************************************************************
 * Small utility function used to parse discontinuous headers safely. Copies
 * i_buf_len bytes of data to a buffer and returns the size copied.
 * It also solves some alignment problems on non-IA-32, non-PPC processors.
 * This is a variation on the theme of input_ext-dec.h:GetChunk().
 *****************************************************************************/
static inline size_t MoveChunk( byte_t * p_dest, data_packet_t ** pp_data_src,
                                byte_t ** pp_src, size_t i_buf_len )
{
    size_t i_available;

    i_available = (ptrdiff_t)((*pp_data_src)->p_payload_end - *pp_src);
    if( i_available >= i_buf_len )
    {
        if( p_dest != NULL )
            memcpy( p_dest, *pp_src, i_buf_len );
        *pp_src += i_buf_len;
        return( i_buf_len );
    }
    else
    {
        size_t i_init_len = i_buf_len;

        do
        {
            if( p_dest != NULL )
                memcpy( p_dest, *pp_src, i_available );
            *pp_data_src = (*pp_data_src)->p_next;
            i_buf_len -= i_available;
            p_dest += i_available;
            if( *pp_data_src == NULL )
            {
                *pp_src = NULL;
                return( i_init_len - i_buf_len );
            }
            *pp_src = (*pp_data_src)->p_payload_start;

            i_available = (ptrdiff_t)((*pp_data_src)->p_payload_end - *pp_src);
        }
        while( i_available <= i_buf_len );

        if( i_buf_len )
        {
            if( p_dest != NULL )
                memcpy( p_dest, *pp_src, i_buf_len );
            *pp_src += i_buf_len;
        }
        return( i_init_len );
    }
}

/*****************************************************************************
 * ParsePES
 *****************************************************************************
 * Parse a finished PES packet and analyze its header.
 *****************************************************************************/
#define PES_HEADER_SIZE     7
static void ParsePES( input_thread_t * p_input, es_descriptor_t * p_es )
{
    data_packet_t * p_data;
    byte_t *        p_byte;
    byte_t          p_header[PES_HEADER_SIZE];
    int             i_done;

#define p_pes (p_es->p_pes)

    /* Parse the header. The header has a variable length, but in order
     * to improve the algorithm, we will read the 14 bytes we may be
     * interested in */
    p_data = p_pes->p_first;
    p_byte = p_data->p_payload_start;
    i_done = 0;

    if( MoveChunk( p_header, &p_data, &p_byte, PES_HEADER_SIZE )
            != PES_HEADER_SIZE )
    {
        msg_Warn( p_input, "PES packet too short to have a header" );
        input_DeletePES( p_input->p_method_data, p_pes );
        p_pes = NULL;
        return;
    }

    /* Get the PES size if defined */
    p_es->i_pes_real_size = U16_AT(p_header + 4);
    if( p_es->i_pes_real_size )
    {
        p_es->i_pes_real_size += 6;
    }

    /* First read the 6 header bytes common to all PES packets:
     * use them to test the PES validity */
    if( (p_header[0] || p_header[1] || (p_header[2] != 1)) )
    {
        /* packet_start_code_prefix != 0x000001 */
        msg_Warn( p_input, "data loss, PES packet does not start with 000001" );
        input_DeletePES( p_input->p_method_data, p_pes );
        p_pes = NULL;
    }
    else
    {
        unsigned int i_pes_header_size, i_payload_size;

        if ( p_es->i_pes_real_size &&
             (p_es->i_pes_real_size != p_pes->i_pes_size) )
        {
            /* PES_packet_length is set and != total received payload */
            /* Warn the decoder that the data may be corrupt. */
            msg_Warn( p_input, "packet corrupted, PES sizes do not match" );
        }

        switch( p_header[3] )
        {
        case 0xBC:  /* Program stream map */
        case 0xBE:  /* Padding */
        case 0xBF:  /* Private stream 2 */
        case 0xB0:  /* ECM */
        case 0xB1:  /* EMM */
        case 0xFF:  /* Program stream directory */
        case 0xF2:  /* DSMCC stream */
        case 0xF8:  /* ITU-T H.222.1 type E stream */
            /* The payload begins immediately after the 6 bytes header, so
             * we have finished with the parsing */
            i_pes_header_size = 6;
            break;

        default:
            if( (p_header[6] & 0xC0) == 0x80 )
            {
                /* MPEG-2 : the PES header contains at least 3 more bytes. */
                size_t      i_max_len;
                vlc_bool_t  b_has_pts, b_has_dts;
                byte_t      p_full_header[12];

                p_pes->b_data_alignment = p_header[6] & 0x04;

                i_max_len = MoveChunk( p_full_header, &p_data, &p_byte, 12 );
                if( i_max_len < 2 )
                {
                    msg_Warn( p_input,
                              "PES packet too short to have a MPEG-2 header" );
                    input_DeletePES( p_input->p_method_data,
                                            p_pes );
                    p_pes = NULL;
                    return;
                }

                b_has_pts = p_full_header[0] & 0x80;
                b_has_dts = p_full_header[0] & 0x40;
                i_pes_header_size = p_full_header[1] + 9;

                /* Now parse the optional header extensions */
                if( b_has_pts )
                {
                    if( i_max_len < 7 )
                    {
                        msg_Warn( p_input,
                             "PES packet too short to have a MPEG-2 header" );
                        input_DeletePES( p_input->p_method_data,
                                                p_pes );
                        p_pes = NULL;
                        return;
                    }
                    p_pes->i_pts = input_ClockGetTS( p_input, p_es->p_pgrm,
                    ( ((mtime_t)(p_full_header[2] & 0x0E) << 29) |
                      ((mtime_t)(p_full_header[3]) << 22) |
                      ((mtime_t)(p_full_header[4] & 0xFE) << 14) |
                      ((mtime_t)p_full_header[5] << 7) |
                      ((mtime_t)p_full_header[6] >> 1) ) );

                    if( b_has_dts )
                    {
                        if( i_max_len < 12 )
                        {
                            msg_Warn( p_input,
                              "PES packet too short to have a MPEG-2 header" );
                            input_DeletePES( p_input->p_method_data,
                                                    p_pes );
                            p_pes = NULL;
                            return;
                        }
                        p_pes->i_dts = input_ClockGetTS( p_input, p_es->p_pgrm,
                        ( ((mtime_t)(p_full_header[7] & 0x0E) << 29) |
                          (((mtime_t)U16_AT(p_full_header + 8) << 14)
                                - (1 << 14)) |
                          ((mtime_t)U16_AT(p_full_header + 10) >> 1) ) );
                    }
                }
            }
            else
            {
                /* Probably MPEG-1 */
                vlc_bool_t      b_has_pts, b_has_dts;

                i_pes_header_size = 6;
                p_data = p_pes->p_first;
                p_byte = p_data->p_payload_start;
                /* Cannot fail because the previous one succeeded. */
                MoveChunk( NULL, &p_data, &p_byte, 6 );

                while( *p_byte == 0xFF && i_pes_header_size < 23 )
                {
                    i_pes_header_size++;
                    if( MoveChunk( NULL, &p_data, &p_byte, 1 ) != 1 )
                    {
                        msg_Warn( p_input,
                            "PES packet too short to have a MPEG-1 header" );
                        input_DeletePES( p_input->p_method_data, p_pes );
                        p_pes = NULL;
                        return;
                    }
                }
                if( i_pes_header_size == 23 )
                {
                    msg_Warn( p_input, "too much MPEG-1 stuffing" );
                    input_DeletePES( p_input->p_method_data, p_pes );
                    p_pes = NULL;
                    return;
                }

                if( (*p_byte & 0xC0) == 0x40 )
                {
                    /* Don't ask why... --Meuuh */
                    /* Erm... why ? --Sam */
                    /* Well... According to the recommendation, it is for
                     * STD_buffer_scale and STD_buffer_size. --Meuuh */
                    i_pes_header_size += 2;
                    if( MoveChunk( NULL, &p_data, &p_byte, 2 ) != 2 )
                    {
                        msg_Warn( p_input,
                            "PES packet too short to have a MPEG-1 header" );
                        input_DeletePES( p_input->p_method_data, p_pes );
                        p_pes = NULL;
                        return;
                    }
                }

                i_pes_header_size++;

                b_has_pts = *p_byte & 0x20;
                b_has_dts = *p_byte & 0x10;

                if( b_has_pts )
                {
                    byte_t      p_ts[5];

                    i_pes_header_size += 4;
                    if( MoveChunk( p_ts, &p_data, &p_byte, 5 ) != 5 )
                    {
                        msg_Warn( p_input,
                            "PES packet too short to have a MPEG-1 header" );
                        input_DeletePES( p_input->p_method_data, p_pes );
                        p_pes = NULL;
                        return;
                    }

                    p_pes->i_pts = input_ClockGetTS( p_input, p_es->p_pgrm,
                       ( ((mtime_t)(p_ts[0] & 0x0E) << 29) |
                         (((mtime_t)U32_AT(p_ts) & 0xFFFE00) << 6) |
                         ((mtime_t)p_ts[3] << 7) |
                         ((mtime_t)p_ts[4] >> 1) ) );

                    if( b_has_dts )
                    {
                        i_pes_header_size += 5;
                        if( MoveChunk( p_ts, &p_data, &p_byte, 5 ) != 5 )
                        {
                            msg_Warn( p_input,
                              "PES packet too short to have a MPEG-1 header" );
                            input_DeletePES( p_input->p_method_data, p_pes );
                            p_pes = NULL;
                            return;
                        }

                        p_pes->i_dts = input_ClockGetTS( p_input,
                                                         p_es->p_pgrm,
                            ( ((mtime_t)(p_ts[0] & 0x0E) << 29) |
                              (((mtime_t)U32_AT(p_ts) & 0xFFFE00) << 6) |
                              ((mtime_t)p_ts[3] << 7) |
                              ((mtime_t)p_ts[4] >> 1) ) );
                    }
                }
            }

            break;
        }

        /* Welcome to the kludge area ! --Meuuh */
        if ( p_es->i_fourcc == VLC_FOURCC('a','5','2','b')
              || p_es->i_fourcc == VLC_FOURCC('d','t','s','b') )
        {
            /* With A/52 or DTS audio, we need to skip the first 4 bytes */
            i_pes_header_size += 4;
        }

        if ( p_es->i_fourcc == VLC_FOURCC('l','p','c','b')
              || p_es->i_fourcc == VLC_FOURCC('s','p','u','b')
              || p_es->i_fourcc == VLC_FOURCC('s','d','d','b') )