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/*
* section and descriptor parser
*
* Copyright (C) 2005 Andrew de Quincey (adq_dvb@lidskialf.net)
*
* This library 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 library 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 library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
*/
#ifndef _UCSI_TRANSPORT_PACKET_H
#define _UCSI_TRANSPORT_PACKET_H 1
#ifdef __cplusplus
extern "C"
{
#endif
#include <stdint.h>
#include "descriptor.h"
#define TRANSPORT_PACKET_LENGTH 188
#define TRANSPORT_PACKET_SYNC 0x47
#define TRANSPORT_MAX_PIDS 0x2000
#define TRANSPORT_NULL_PID 0x1fff
/**
* Enumeration of adaptation field control values.
*/
enum transport_adaptation_field_control {
transport_adaptation_field_control_reserved = 0x00,
transport_adaptation_field_control_payload_only = 0x01,
transport_adaptation_field_control_adaptation_only = 0x02,
transport_adaptation_field_control_adaptation_payload = 0x03,
};
/**
* Enumeration of scrambling control values.
*/
enum transport_scrambling_control {
transport_scrambling_control_unscrambled = 0x00,
transport_scrambling_control_user_1 = 0x01,
transport_scrambling_control_user_2 = 0x02,
transport_scrambling_control_user_3 = 0x03,
};
/**
* Enumeration of adaptation flags.
*/
enum transport_adaptation_flags {
transport_adaptation_flag_discontinuity = 0x80,
transport_adaptation_flag_random_access = 0x40,
transport_adaptation_flag_es_priority = 0x20,
transport_adaptation_flag_pcr = 0x10,
transport_adaptation_flag_opcr = 0x08,
transport_adaptation_flag_splicing_point = 0x04,
transport_adaptation_flag_private_data = 0x02,
transport_adaptation_flag_extension = 0x01,
};
/**
* Enumeration of adaptation extension flags.
*/
enum transport_adaptation_extension_flags {
transport_adaptation_extension_flag_ltw = 0x80,
transport_adaptation_extension_flag_piecewise_rate = 0x40,
transport_adaptation_extension_flag_seamless_splice = 0x20,
};
/**
* Enumeration of flags controlling which values to extract using the
* transport_packet_values_extract() function.
*/
enum transport_value {
/* normal adaptation */
transport_value_pcr = 0x0001,
transport_value_opcr = 0x0002,
transport_value_splice_countdown = 0x0004,
transport_value_private_data = 0x0008,
/* extension adaptation */
transport_value_ltw = 0x0100,
transport_value_piecewise_rate = 0x0200,
transport_value_seamless_splice = 0x0400,
};
/**
* Structure describing a transport packet header.
*/
struct transport_packet {
uint8_t sync_byte;
EBIT4(uint8_t transport_error_indicator : 1; ,
uint8_t payload_unit_start_indicator : 1; ,
uint8_t transport_priority : 1; ,
uint8_t pid_hi : 5; );
uint8_t pid_lo;
EBIT3(uint8_t transport_scrambling_control : 2; ,
uint8_t adaptation_field_control : 2; ,
uint8_t continuity_counter : 4; );
/* values */
} __ucsi_packed;
/**
* Structure to extract values into using the transport_packet_values_extract()
* function.
*/
struct transport_values {
enum transport_adaptation_flags flags; /* always extracted */
uint8_t *payload; /* always extracted */
uint16_t payload_length; /* always extracted */
uint64_t pcr;
uint64_t opcr;
uint8_t splice_countdown;
uint8_t private_data_length;
uint8_t *private_data;
uint16_t ltw_offset;
uint32_t piecewise_rate;
uint8_t splice_type;
uint64_t dts_next_au;
};
/**
* Extract the PID from a transport packet.
*
* @param pkt The packet.
* @return The PID.
*/
static inline int transport_packet_pid(struct transport_packet *pkt)
{
return (pkt->pid_hi << 8) | (pkt->pid_lo);
}
/**
* Process a buffer into a transport packet.
*
* @param buf Raw buffer. Note, this function assumes there are 188 bytes available.
* @return transport_packet pointer, or NULL on error.
*/
static inline struct transport_packet *transport_packet_init(unsigned char *buf)
{
struct transport_packet *pkt = (struct transport_packet*) buf;
if (pkt->sync_byte != TRANSPORT_PACKET_SYNC)
return NULL;
if (transport_packet_pid(pkt) >= TRANSPORT_MAX_PIDS)
return NULL;
return pkt;
}
/**
* Check the continuity counter for a packet in a PID stream.
*
* @param pkt transport_packet to check.
* @param discontinuity_indicator Set to 1 if the packet's discontinuity_indicator flag is set.
* @param cstate Pointer to a single 8 bit character, used to store state for validating
* continuity. To initialise the state, simply set it to 0 before the first call.
* @return 0 if the continuity was correct, or nonzero on error. cstate will not be updated on error,
* it is up to the caller to clear it to accept the next packet.
*/
extern int transport_packet_continuity_check(struct transport_packet *pkt,
int discontinuity_indicator, unsigned char *cstate);
/**
* Extract selected fields from a transport packet.
*
* @param pkt The packet.
* @param out Destination structure for values.
* @param extract Orred bitmask of enum transport_value - tells it what fields
* to extract if they are available.
* @return < 0 => error. Otherwise, an orred bitmask of enum transport_value
* telling you what fields were successfully extracted.
*/
extern int transport_packet_values_extract(struct transport_packet *pkt,
struct transport_values *out,
enum transport_value extract);
#ifdef __cplusplus
}
#endif
#endif
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