util.hpp

#ifndef INCLUDE_UTIL_HPP
#define INCLUDE_UTIL_HPP

#include <stddef.h>
#include <stdint.h>

constexpr uint8_t ADTS_TRANSPORT = 0x0f;
constexpr uint8_t PES_ID3_METADATA = 0x15;
constexpr uint8_t AVC_VIDEO = 0x1b;
constexpr uint8_t H_265_VIDEO = 0x24;

struct PSI
{
    int table_id;
    int section_length;
    int version_number;
    int current_next_indicator;
    int continuity_counter;
    int data_count;
    uint8_t data[1024];
};

struct PMT
{
    int pmt_pid;
    int program_number;
    int version_number;
    int pcr_pid;
    int first_video_stream_type;
    int first_video_pid;
    int first_adts_audio_pid;
    int first_id3_metadata_pid;
    PSI psi;
};

struct PAT
{
    int transport_stream_id;
    int version_number;
    PMT first_pmt;
    PSI psi;
};

uint32_t calc_crc32(const uint8_t *data, int data_size, uint32_t crc = 0xffffffff);
int extract_psi(PSI *psi, const uint8_t *payload, int payload_size, int unit_start, int counter);
void extract_pat(PAT *pat, const uint8_t *payload, int payload_size, int unit_start, int counter);
void extract_pmt(PMT *pmt, const uint8_t *payload, int payload_size, int unit_start, int counter);
int contains_nal_idr_or_cra(int *nal_state, const uint8_t *payload, int payload_size, bool h_265);
int get_ts_payload_size(const uint8_t *packet);
int64_t get_pes_timestamp(const uint8_t *data_5bytes);

inline int extract_ts_header_sync(const uint8_t *packet) { return packet[0]; }
inline int extract_ts_header_unit_start(const uint8_t *packet) { return !!(packet[1] & 0x40); }
inline int extract_ts_header_pid(const uint8_t *packet) { return ((packet[1] & 0x1f) << 8) | packet[2]; }
inline int extract_ts_header_adaptation(const uint8_t *packet) { return (packet[3] >> 4) & 0x03; }
inline int extract_ts_header_counter(const uint8_t *packet) { return packet[3] & 0x0f; }

inline uint8_t extract_bit(const uint8_t *data, size_t pos)
{
    return (data[pos >> 3] >> (7 - (pos & 7))) & 1;
}

inline bool read_bool(const uint8_t *data, size_t &pos)
{
    return !!extract_bit(data, pos++);
}

inline int read_bits(const uint8_t *data, size_t &pos, int n)
{
    int r = 0;
    while (--n >= 0) {
        r |= extract_bit(data, pos++) << n;
    }
    return r;
}

#endif