rtp.h

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#ifndef JANUS_RTP_H
#define JANUS_RTP_H

#include <arpa/inet.h>
#ifdef __MACH__
#include <machine/endian.h>
#define __BYTE_ORDER BYTE_ORDER
#define __BIG_ENDIAN BIG_ENDIAN
#define __LITTLE_ENDIAN LITTLE_ENDIAN
#else
#include <endian.h>
#endif
#include <inttypes.h>
#include <string.h>
#include <glib.h>
#include <jansson.h>

#define RTP_HEADER_SIZE 12

typedef struct rtp_header
{
#if __BYTE_ORDER == __BIG_ENDIAN
        uint16_t version:2;
        uint16_t padding:1;
        uint16_t extension:1;
        uint16_t csrccount:4;
        uint16_t markerbit:1;
        uint16_t type:7;
#elif __BYTE_ORDER == __LITTLE_ENDIAN
        uint16_t csrccount:4;
        uint16_t extension:1;
        uint16_t padding:1;
        uint16_t version:2;
        uint16_t type:7;
        uint16_t markerbit:1;
#endif
        uint16_t seq_number;
        uint32_t timestamp;
        uint32_t ssrc;
        uint32_t csrc[16];
} rtp_header;
typedef rtp_header janus_rtp_header;

typedef struct janus_rtp_packet {
        char *data;
        gint length;
        gint64 created;
        gint64 last_retransmit;
} janus_rtp_packet;

typedef struct janus_rtp_header_extension {
        uint16_t type;
        uint16_t length;
} janus_rtp_header_extension;

#define JANUS_RTP_EXTMAP_AUDIO_LEVEL            "urn:ietf:params:rtp-hdrext:ssrc-audio-level"

#define JANUS_RTP_EXTMAP_TOFFSET                        "urn:ietf:params:rtp-hdrext:toffset"

#define JANUS_RTP_EXTMAP_ABS_SEND_TIME          "http://www.webrtc.org/experiments/rtp-hdrext/abs-send-time"

#define JANUS_RTP_EXTMAP_VIDEO_ORIENTATION      "urn:3gpp:video-orientation"

#define JANUS_RTP_EXTMAP_TRANSPORT_WIDE_CC      "http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions-01"

#define JANUS_RTP_EXTMAP_PLAYOUT_DELAY          "http://www.webrtc.org/experiments/rtp-hdrext/playout-delay"

#define JANUS_RTP_EXTMAP_MID                            "urn:ietf:params:rtp-hdrext:sdes:mid"

#define JANUS_RTP_EXTMAP_RID                            "urn:ietf:params:rtp-hdrext:sdes:rtp-stream-id"

#define JANUS_RTP_EXTMAP_REPAIRED_RID           "urn:ietf:params:rtp-hdrext:sdes:repaired-rtp-stream-id"

#define JANUS_RTP_EXTMAP_FRAME_MARKING          "http://tools.ietf.org/html/draft-ietf-avtext-framemarking-07"

#define JANUS_RTP_EXTMAP_ENCRYPTED                      "urn:ietf:params:rtp-hdrext:encrypt"


typedef enum janus_audiocodec {
        JANUS_AUDIOCODEC_NONE,
        JANUS_AUDIOCODEC_OPUS,
        JANUS_AUDIOCODEC_PCMU,
        JANUS_AUDIOCODEC_PCMA,
        JANUS_AUDIOCODEC_G722,
        JANUS_AUDIOCODEC_ISAC_32K,
        JANUS_AUDIOCODEC_ISAC_16K
} janus_audiocodec;
const char *janus_audiocodec_name(janus_audiocodec acodec);
janus_audiocodec janus_audiocodec_from_name(const char *name);
int janus_audiocodec_pt(janus_audiocodec acodec);

typedef enum janus_videocodec {
        JANUS_VIDEOCODEC_NONE,
        JANUS_VIDEOCODEC_VP8,
        JANUS_VIDEOCODEC_VP9,
        JANUS_VIDEOCODEC_H264
} janus_videocodec;
const char *janus_videocodec_name(janus_videocodec vcodec);
janus_videocodec janus_videocodec_from_name(const char *name);
int janus_videocodec_pt(janus_videocodec vcodec);


gboolean janus_is_rtp(char *buf, guint len);

char *janus_rtp_payload(char *buf, int len, int *plen);

int janus_rtp_header_extension_get_id(const char *sdp, const char *extension);

const char *janus_rtp_header_extension_get_from_id(const char *sdp, int id);

int janus_rtp_header_extension_parse_audio_level(char *buf, int len, int id, int *level);

int janus_rtp_header_extension_parse_video_orientation(char *buf, int len, int id,
        gboolean *c, gboolean *f, gboolean *r1, gboolean *r0);

int janus_rtp_header_extension_parse_playout_delay(char *buf, int len, int id,
        uint16_t *min_delay, uint16_t *max_delay);

int janus_rtp_header_extension_parse_mid(char *buf, int len, int id,
        char *sdes_item, int sdes_len);

int janus_rtp_header_extension_parse_rid(char *buf, int len, int id,
        char *sdes_item, int sdes_len);

int janus_rtp_header_extension_parse_framemarking(char *buf, int len, int id, janus_videocodec codec, uint8_t *tid);

int janus_rtp_header_extension_parse_transport_wide_cc(char *buf, int len, int id,
        uint16_t *transSeqNum);

int janus_rtp_header_extension_replace_id(char *buf, int len, int id, int new_id);

typedef struct janus_rtp_switching_context {
        uint32_t last_ssrc, last_ts, base_ts, base_ts_prev, prev_ts, target_ts, start_ts;
        uint16_t last_seq, prev_seq, base_seq, base_seq_prev;
        gboolean seq_reset, new_ssrc;
        gint16 seq_offset;
        gint32 prev_delay, active_delay, ts_offset;
        gint64 last_time, reference_time, start_time, evaluating_start_time;
} janus_rtp_switching_context;

void janus_rtp_switching_context_reset(janus_rtp_switching_context *context);

void janus_rtp_header_update(janus_rtp_header *header, janus_rtp_switching_context *context, gboolean video);

#define RTP_AUDIO_SKEW_TH_MS 120
#define RTP_VIDEO_SKEW_TH_MS 120
#define SKEW_DETECTION_WAIT_TIME_SECS 10

int janus_rtp_skew_compensate_audio(janus_rtp_header *header, janus_rtp_switching_context *context, gint64 now);
int janus_rtp_skew_compensate_video(janus_rtp_header *header, janus_rtp_switching_context *context, gint64 now);


typedef struct janus_rtp_simulcasting_context {
        gint rid_ext_id;
        gint framemarking_ext_id;
        int substream;
        int substream_target;
        int templayer;
        int templayer_target;
        gint64 last_relayed;
        gboolean changed_substream;
        gboolean changed_temporal;
        gboolean need_pli;
} janus_rtp_simulcasting_context;

void janus_rtp_simulcasting_context_reset(janus_rtp_simulcasting_context *context);

void janus_rtp_simulcasting_prepare(json_t *simulcast, int *rid_ext_id, int *framemarking_ext_id, uint32_t *ssrcs, char **rids);

gboolean janus_rtp_simulcasting_context_process_rtp(janus_rtp_simulcasting_context *context,
        char *buf, int len, uint32_t *ssrcs, char **rids,
        janus_videocodec vcodec, janus_rtp_switching_context *sc);

#endif