dr_83.c

Dvbstreamer 用在解析MPTS的部分内容

/*
Copyright (C) 2006  Adam Charrett

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

dr_83.c

Decode Logical Channel Number Descriptor.

*/
#include "config.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>

#include "dvbpsi.h"
#include "../dvbpsi_private.h"
#include "descriptor.h"

#include "dr_83.h"

/*****************************************************************************
 * dvbpsi_DecodeLCNDr
 *****************************************************************************/
dvbpsi_lcn_dr_t *dvbpsi_DecodeLCNDr(dvbpsi_descriptor_t *p_descriptor)
{
    dvbpsi_lcn_dr_t *p_decoded;
    int i;
    /* Check the tag */
    if (p_descriptor->i_tag != 0x83)
    {
        return NULL;
    }

    /* Don't decode twice */
    if (p_descriptor->p_decoded)
    {
        return p_descriptor->p_decoded;
    }

    /* Check length */
    if (p_descriptor->i_length % 4)
    {
        return NULL;
    }
    
    p_decoded = (dvbpsi_lcn_dr_t*)malloc(sizeof(dvbpsi_lcn_dr_t));
    if (!p_decoded)
    {
        return NULL;
    }

    p_decoded->i_number_of_entries = p_descriptor->i_length / 4;

    for (i = 0; i < p_decoded->i_number_of_entries; i ++)
    {
        p_decoded->p_entries[i].i_service_id = (p_descriptor->p_data[i * 4] << 8) |
                                                p_descriptor->p_data[(i * 4) + 1];

        p_decoded->p_entries[i].b_visible_service_flag = (p_descriptor->p_data[(i * 4) + 2] >> 7) & 1;

        p_decoded->p_entries[i].i_logical_channel_number = ((p_descriptor->p_data[(i * 4) + 2] << 8) |
                                                             p_descriptor->p_data[(i * 4) + 3]) & 0x3ff;
        
    }

    p_descriptor->p_decoded = (void*)p_decoded;

    return p_decoded;
}