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Diffstat (limited to 'lib/libucsi/transport_packet.h')
| -rw-r--r-- | lib/libucsi/transport_packet.h | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/lib/libucsi/transport_packet.h b/lib/libucsi/transport_packet.h new file mode 100644 index 0000000..6314eca --- /dev/null +++ b/lib/libucsi/transport_packet.h @@ -0,0 +1,195 @@ +/* + * 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 |