File: rtcp.h

package info (click to toggle)
janus 0.7.3-2
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, sid
  • size: 15,360 kB
  • sloc: ansic: 130,260; makefile: 554; sh: 153; lisp: 9
file content (538 lines) | stat: -rw-r--r-- 21,618 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
/*! \file    rtcp.h
 * \author   Lorenzo Miniero <lorenzo@meetecho.com>
 * \copyright GNU General Public License v3
 * \brief    RTCP processing (headers)
 * \details  Implementation of the RTCP messages. RTCP messages coming
 * through the server are parsed and, if needed (according to
 * http://tools.ietf.org/html/draft-ietf-straw-b2bua-rtcp-00),
 * fixed before they are sent to the peers (e.g., to fix SSRCs that may
 * have been changed by the server). Methods to generate FIR messages
 * and generate/cap REMB messages are provided as well.
 *
 * \ingroup protocols
 * \ref protocols
 */

#ifndef _JANUS_RTCP_H
#define _JANUS_RTCP_H

#include <arpa/inet.h>
#ifdef __MACH__
#include <machine/endian.h>
#else
#include <endian.h>
#endif
#include <inttypes.h>
#include <string.h>

/*! \brief RTCP Packet Types (http://www.networksorcery.com/enp/protocol/rtcp.htm) */
typedef enum {
    RTCP_FIR = 192,
    RTCP_SR = 200,
    RTCP_RR = 201,
    RTCP_SDES = 202,
    RTCP_BYE = 203,
    RTCP_APP = 204,
    RTCP_RTPFB = 205,
    RTCP_PSFB = 206,
    RTCP_XR = 207,
} rtcp_type;
typedef rtcp_type janus_rtcp_type;


/*! \brief RTCP Header (http://tools.ietf.org/html/rfc3550#section-6.1) */
typedef struct rtcp_header
{
#if __BYTE_ORDER == __BIG_ENDIAN
	uint16_t version:2;
	uint16_t padding:1;
	uint16_t rc:5;
	uint16_t type:8;
#elif __BYTE_ORDER == __LITTLE_ENDIAN
	uint16_t rc:5;
	uint16_t padding:1;
	uint16_t version:2;
	uint16_t type:8;
#endif
	uint16_t length:16;
} rtcp_header;
typedef rtcp_header janus_rtcp_header;

/*! \brief RTCP Sender Information (http://tools.ietf.org/html/rfc3550#section-6.4.1) */
typedef struct sender_info
{
	uint32_t ntp_ts_msw;
	uint32_t ntp_ts_lsw;
	uint32_t rtp_ts;
	uint32_t s_packets;
	uint32_t s_octets;
} sender_info;
typedef sender_info janus_sender_info;

/*! \brief RTCP Report Block (http://tools.ietf.org/html/rfc3550#section-6.4.1) */
typedef struct report_block
{
	uint32_t ssrc;
	uint32_t flcnpl;
	uint32_t ehsnr;
	uint32_t jitter;
	uint32_t lsr;
	uint32_t delay;
} report_block;
typedef report_block janus_report_block;

/*! \brief RTCP Sender Report (http://tools.ietf.org/html/rfc3550#section-6.4.1) */
typedef struct rtcp_sr
{
	rtcp_header header;
	uint32_t ssrc;
	sender_info si;
	report_block rb[1];
} rtcp_sr;
typedef rtcp_sr janus_rtcp_sr;

/*! \brief RTCP Receiver Report (http://tools.ietf.org/html/rfc3550#section-6.4.2) */
typedef struct rtcp_rr
{
	rtcp_header header;
	uint32_t ssrc;
	report_block rb[1];
} rtcp_rr;
typedef rtcp_rr janus_rtcp_rr;

/*! \brief RTCP SDES (http://tools.ietf.org/html/rfc3550#section-6.5) */
typedef struct rtcp_sdes_chunk
{
	uint32_t ssrc;
} rtcp_sdes_chunk;
typedef rtcp_sdes_chunk janus_rtcp_sdes_chunk;

typedef struct rtcp_sdes_item
{
	uint8_t type;
	uint8_t len;
	char content[1];
} rtcp_sdes_item;
typedef rtcp_sdes_item janus_rtcp_sdes_item;

typedef struct rtcp_sdes
{
	rtcp_header header;
	rtcp_sdes_chunk chunk;
	rtcp_sdes_item item;
} rtcp_sdes;
typedef rtcp_sdes janus_rtcp_sdes;

/*! \brief RTCP BYE (http://tools.ietf.org/html/rfc3550#section-6.6) */
typedef struct rtcp_bye
{
	rtcp_header header;
	uint32_t ssrc[1];
} rtcp_bye;
typedef rtcp_bye janus_rtcp_bye;

/*! \brief RTCP APP (http://tools.ietf.org/html/rfc3550#section-6.7) */
typedef struct rtcp_app
{
	rtcp_header header;
	uint32_t ssrc;
	char name[4];
} rtcp_app;
typedef rtcp_app janus_rtcp_app;

/*! \brief RTCP NACK (http://tools.ietf.org/html/rfc4585#section-6.2.1) */
typedef struct rtcp_nack
{
	/*! \brief Packet ID */
	uint16_t pid;
	/*! \brief bitmask of following lost packets */
	uint16_t blp;
} rtcp_nack;
typedef rtcp_nack janus_rtcp_nack;

/*! \brief Janus representation (linked list) of sequence numbers to send again */
typedef struct janus_nack {
	/*! \brief Sequence number to send again */
	uint16_t seq_no;
	/*! \brief Next element in the linked list */
	struct janus_nack *next;
} janus_nack;


/*! \brief RTCP REMB (http://tools.ietf.org/html/draft-alvestrand-rmcat-remb-03) */
typedef struct rtcp_remb
{
	/*! \brief Unique identifier ('R' 'E' 'M' 'B') */
	char id[4];
	/*! \brief Num SSRC, Br Exp, Br Mantissa (bit mask) */
	uint32_t bitrate;
	/*! \brief SSRC feedback (we expect at max three SSRCs in there) */
	uint32_t ssrc[3];
} rtcp_remb;
typedef rtcp_remb janus_rtcp_fb_remb;


/*! \brief RTCP FIR (http://tools.ietf.org/search/rfc5104#section-4.3.1.1) */
typedef struct rtcp_fir
{
	/*! \brief SSRC of the media sender that needs to send a key frame */
	uint32_t ssrc;
	/*! \brief Sequence number (only the first 8 bits are used, the other 24 are reserved) */
	uint32_t seqnr;
} rtcp_fir;
typedef rtcp_fir janus_rtcp_fb_fir;


/*! \brief RTCP-FB (http://tools.ietf.org/html/rfc4585) */
typedef struct rtcp_fb
{
	/*! \brief Common header */
	rtcp_header header;
	/*! \brief Sender SSRC */
	uint32_t ssrc;
	/*! \brief Media source */
	uint32_t media;
	/*! \brief Feedback Control Information */
	char fci[1];
} rtcp_fb;
typedef rtcp_fb janus_rtcp_fb;

/*! \brief RTCP Extended Report Block (https://tools.ietf.org/html/rfc3611#section-3) */
typedef struct extended_report_block
{
	/*! \brief Block type (BT) */
	uint8_t blocktype;
	/*! \brief Type-specific */
	uint8_t typesp;
	/*! \brief Block length */
	uint16_t length;
	/*! \brief Content (variable length) */
	char content[1];

} extended_report_block;
typedef extended_report_block janus_extended_report_block;

/*! \brief RTCP Extended Report (https://tools.ietf.org/html/rfc3611#section-2) */
typedef struct rtcp_xr
{
	rtcp_header header;
	uint32_t ssrc;
	extended_report_block erb[1];
} rtcp_xr;
typedef rtcp_xr janus_rtcp_xr;


/*! \brief Internal RTCP state context (for RR/SR) */
typedef struct rtcp_context
{
	/* Whether we received any RTP packet at all (don't send RR otherwise) */
	uint8_t rtp_recvd:1;
	uint32_t rtp_last_inorder_ts;
	int64_t rtp_last_inorder_time;

	uint16_t max_seq_nr;
	uint16_t seq_cycle;
	uint16_t base_seq;
	/* Payload type */
	uint16_t pt;

	/* RFC 3550 A.8 Interarrival Jitter */
	int64_t transit;
	double jitter, jitter_remote;
	/* Timestamp base (e.g., 48000 for opus audio, or 90000 for video) */
	uint32_t tb;

	/* Last SR received */
	uint32_t lsr;
	/* Monotonic time of last SR received */
	int64_t lsr_ts;

	/* Last RR/SR we sent */
	int64_t last_sent;

	/* Estimated round-trip time */
	uint32_t rtt;

	/* RFC 3550 A.3 */
	uint32_t received;
	uint32_t received_prior;
	uint32_t expected;
	uint32_t expected_prior;
	uint32_t lost, lost_remote;

	uint32_t retransmitted;
	uint32_t retransmitted_prior;

	/* Inbound RR process */
	int64_t rr_last_ts;
	uint32_t rr_last_ehsnr;
	uint32_t rr_last_lost;
	uint32_t rr_last_nack_count;
	gint sent_packets_since_last_rr;
	gint nack_count;

	/* Link quality estimations */
	double in_link_quality;
	double in_media_link_quality;
	double out_link_quality;
	double out_media_link_quality;
} rtcp_context;
typedef rtcp_context janus_rtcp_context;

/*! \brief Stores transport wide packet reception statistics */
typedef struct rtcp_transport_wide_cc_stats
{
	/*! \brief Transwport wide sequence number */
	guint32 transport_seq_num;
	/*! \brief Reception time */
	guint64 timestamp;
} rtcp_transport_wide_cc_stats;
typedef rtcp_transport_wide_cc_stats janus_rtcp_transport_wide_cc_stats;

/*! \brief Method to retrieve the estimated round-trip time from an existing RTCP context
 * @param[in] ctx The RTCP context to query
 * @returns The estimated round-trip time */
uint32_t janus_rtcp_context_get_rtt(janus_rtcp_context *ctx);
/*! \brief Method to retrieve the total number of lost packets from an existing RTCP context
 * @param[in] ctx The RTCP context to query
 * @param[in] remote Whether we're quering the remote (provided by peer) or local (computed by Janus) info
 * @returns The total number of lost packets */
uint32_t janus_rtcp_context_get_lost_all(janus_rtcp_context *ctx, gboolean remote);
/*! \brief Method to retrieve the jitter from an existing RTCP context
 * @param[in] ctx The RTCP context to query
 * @param[in] remote Whether we're quering the remote (provided by peer) or local (computed by Janus) info
 * @returns The computed jitter */
uint32_t janus_rtcp_context_get_jitter(janus_rtcp_context *ctx, gboolean remote);
/*! \brief Method to retrieve inbound link quality from an existing RTCP context
 * @param[in] ctx The RTCP context to query
 * @returns Inbound link quality estimation */
uint32_t janus_rtcp_context_get_in_link_quality(janus_rtcp_context *ctx);
/*! \brief Method to retrieve inbound media link quality from an existing RTCP context
 * @param[in] ctx The RTCP context to query
 * @returns Inbound media link quality estimation */
uint32_t janus_rtcp_context_get_in_media_link_quality(janus_rtcp_context *ctx);
/*! \brief Method to retrieve outbound link quality from an existing RTCP context
 * @param[in] ctx The RTCP context to query
 * @returns Outbound link quality estimation */
uint32_t janus_rtcp_context_get_out_link_quality(janus_rtcp_context *ctx);
/*! \brief Method to retrieve outbound media link quality from an existing RTCP context
 * @param[in] ctx The RTCP context to query
 * @returns Outbound media link quality estimation */
uint32_t janus_rtcp_context_get_out_media_link_quality(janus_rtcp_context *ctx);
/*! \brief Method to quickly retrieve the sender SSRC (needed for demuxing RTCP in BUNDLE)
 * @param[in] packet The message data
 * @param[in] len The message data length in bytes
 * @returns The sender SSRC, or 0 in case of error */
guint32 janus_rtcp_get_sender_ssrc(char *packet, int len);
/*! \brief Method to quickly retrieve the received SSRC (needed for demuxing RTCP in BUNDLE)
 * @param[in] packet The message data
 * @param[in] len The message data length in bytes
 * @returns The receiver SSRC, or 0 in case of error */
guint32 janus_rtcp_get_receiver_ssrc(char *packet, int len);

/*! \brief Method to check that a RTCP packet size is at least the minimum necessary (8 bytes)
 *  and to validate the length field against the actual size
 * @param[in] packet The message data
 * @param[in] len The message data length in bytes
 * @returns TRUE if packet is OK, or FALSE in case of error */
gboolean janus_rtcp_check_len(janus_rtcp_header *rtcp, int len);
/*! \brief Method to check if a RTCP packet could contain a Receiver Report
 * @param[in] packet The message data
 * @param[in] len The message data length in bytes
 * @returns TRUE if packet is OK, or FALSE in case of error */
gboolean janus_rtcp_check_rr(janus_rtcp_header *rtcp, int len);
/*! \brief Method to check if a RTCP packet could contain a Sender Report
 * @param[in] packet The message data
 * @param[in] len The message data length in bytes
 * @returns TRUE if packet is OK, or FALSE in case of error */
gboolean janus_rtcp_check_sr(janus_rtcp_header *rtcp, int len);
/*! \brief Method to check if a RTCP packet could contain a Feedback Message
 * with a defined FCI size.
 * @param[in] packet The message data
 * @param[in] len The message data length in bytes
 * @param[in] sizeof_fci The size of a FCI entry
 * @returns TRUE if packet is OK, or FALSE in case of error */
gboolean janus_rtcp_check_fci(janus_rtcp_header *rtcp, int len, int sizeof_fci);
/*! \brief Method to check if a RTCP packet could contain an AFB REMB Message
 * @param[in] packet The message data
 * @param[in] len The message data length in bytes
 * @returns TRUE if packet is OK, or FALSE in case of error */
gboolean janus_rtcp_check_remb(janus_rtcp_header *rtcp, int len);

/*! \brief Helper method to demultiplex RTCP from other protocols
 * @param[in] buf Buffer to inspect
 * @param[in] len Length of the buffer to inspect */
gboolean janus_is_rtcp(char *buf, guint len);

/*! \brief Method to parse/validate an RTCP message
 * @param[in] ctx RTCP context to update, if needed (optional)
 * @param[in] packet The message data
 * @param[in] len The message data length in bytes
 * @returns 0 in case of success, -1 on errors */
int janus_rtcp_parse(janus_rtcp_context *ctx, char *packet, int len);

/*! \brief Method to fix incoming RTCP SR and RR data
 * @param[in] packet The message data
 * @param[in] len The message data length in bytes
 * @param[in] base_ts RTP context base timestamp to compute offset
 * @param[in] base_ts_prev RTP context base timestamp to compute offset
 * @param[in] ssrc_peer The remote SSRC in usage for this stream
 * @param[in] ssrc_local The local SSRC in usage for this stream
 * @param[in] ssrc_expected The expected SSRC for this RTCP packet
 * @param[in] video Whether the RTCP packet contains report for video data
 * @returns The number of fields updated, negative values on errors */
int janus_rtcp_fix_report_data(char *packet, int len, uint32_t base_ts, uint32_t base_ts_prev, uint32_t ssrc_peer, uint32_t ssrc_local, uint32_t ssrc_expected, gboolean video);

/*! \brief Method to fix an RTCP message (http://tools.ietf.org/html/draft-ietf-straw-b2bua-rtcp-00)
 * @param[in] ctx RTCP context to update, if needed (optional)
 * @param[in] packet The message data
 * @param[in] len The message data length in bytes
 * @param[in] fixssrc Whether the method needs to fix the message or just parse it
 * @param[in] fixssrc Whether the method needs to fix the message or just parse it
 * @param[in] newssrcl The SSRC of the sender to put in the message
 * @param[in] newssrcr The SSRC of the receiver to put in the message
 * @returns 0 in case of success, -1 on errors */
int janus_rtcp_fix_ssrc(janus_rtcp_context *ctx, char *packet, int len, int fixssrc, uint32_t newssrcl, uint32_t newssrcr);

/*! \brief Method to filter an outgoing RTCP message (http://tools.ietf.org/html/draft-ietf-straw-b2bua-rtcp-00)
 * @param[in] packet The message data
 * @param[in] len The message data length in bytes
 * @param[in,out] newlen The data length of the filtered RTCP message
 * @returns A pointer to the new RTCP message data, NULL in case all messages have been filtered out */
char *janus_rtcp_filter(char *packet, int len, int *newlen);

/*! \brief Method to quickly process the header of an incoming RTP packet to update the associated RTCP context
 * @param[in] ctx RTCP context to update, if needed (optional)
 * @param[in] packet The RTP packet
 * @param[in] len The packet data length in bytes
 * @param[in] rfc4588_pkt True if this is a RTX packet
 * @param[in] rfc4588_enabled True if this packet comes from a RTX enabled stream
 * @param[in] retransmissions_disabled True if retransmissions are not supported at all for this stream
 * @returns 0 in case of success, -1 on errors */
int janus_rtcp_process_incoming_rtp(janus_rtcp_context *ctx, char *packet, int len, gboolean rfc4588_pkt, gboolean rfc4588_enabled, gboolean retransmissions_disabled);

/*! \brief Method to fill in a Report Block in a Receiver Report
 * @param[in] ctx The RTCP context to use for the report
 * @param[in] rb Pointer to a valid report_block area of the RTCP data
 * @returns 0 in case of success, -1 on errors */
int janus_rtcp_report_block(janus_rtcp_context *ctx, janus_report_block *rb);

/*! \brief Method to quickly fetch the lost packets info from an RR packet, if present
 * \note This is just means as a simple way for plugins to extract this information from
 * a packet, without the need to setup a dedicated RTCP context for tracking the stats flow
 * @param[in] packet The message data
 * @param[in] len The message data length in bytes
 * @param[out] lost The number of lost packets as a whole
 * @param[out] fraction The fraction of lost packets since the last RR/SR
 * @returns TRUE in case of success, FALSE otherwise */
gboolean janus_rtcp_parse_lost_info(char *packet, int len, uint32_t *lost, int *fraction);

/*! \brief Method to check whether an RTCP message contains a BYE message
 * @param[in] packet The message data
 * @param[in] len The message data length in bytes
 * @returns TRUE in case of success, FALSE otherwise */
gboolean janus_rtcp_has_bye(char *packet, int len);

/*! \brief Method to check whether an RTCP message contains a FIR request
 * @param[in] packet The message data
 * @param[in] len The message data length in bytes
 * @returns TRUE in case of success, FALSE otherwise */
gboolean janus_rtcp_has_fir(char *packet, int len);

/*! \brief Method to check whether an RTCP message contains a PLI request
 * @param[in] packet The message data
 * @param[in] len The message data length in bytes
 * @returns TRUE in case of success, FALSE otherwise */
gboolean janus_rtcp_has_pli(char *packet, int len);

/*! \brief Method to parse an RTCP NACK message
 * @param[in] packet The message data
 * @param[in] len The message data length in bytes
 * @returns A list of janus_nack elements containing the sequence numbers to send again */
GSList *janus_rtcp_get_nacks(char *packet, int len);

/*! \brief Method to remove an RTCP NACK message
 * @param[in] packet The message data
 * @param[in] len The message data length in bytes
 * @returns The new message data length in bytes
 * @note This is mostly a placeholder: for the sake of simplicity, whenever we handle
 * some sequence numbers in a NACK, we remove the NACK as a whole before forwarding the
 * RTCP message. Future versions will only selectively remove the sequence numbers that
 * have been handled. */
int janus_rtcp_remove_nacks(char *packet, int len);

/*! \brief Inspect an existing RTCP REMB message to retrieve the reported bitrate
 * @param[in] packet The message data
 * @param[in] len The message data length in bytes
 * @returns The reported bitrate if successful, 0 if no REMB packet was available */
uint32_t janus_rtcp_get_remb(char *packet, int len);

/*! \brief Method to modify an existing RTCP REMB message to cap the reported bitrate
 * @param[in] packet The message data
 * @param[in] len The message data length in bytes
 * @param[in] bitrate The new bitrate to report (e.g., 128000)
 * @returns 0 in case of success, -1 on errors */
int janus_rtcp_cap_remb(char *packet, int len, uint32_t bitrate);

/*! \brief Method to generate a new RTCP SDES message
 * @param[in] packet The buffer data
 * @param[in] len The buffer data length in bytes
 * @param[in] cname The CNAME to write
 * @param[in] cnamelen The CNAME data length in bytes
 * @returns The message data length in bytes, if successful, -1 on errors */
int janus_rtcp_sdes_cname(char *packet, int len, const char *cname, int cnamelen);

/*! \brief Method to generate a new RTCP REMB message to cap the reported bitrate
 * @param[in] packet The buffer data (MUST be at least 24 chars)
 * @param[in] len The message data length in bytes (MUST be 24)
 * @param[in] bitrate The bitrate to report (e.g., 128000)
 * @returns The message data length in bytes, if successful, -1 on errors */
int janus_rtcp_remb(char *packet, int len, uint32_t bitrate);

/*! \brief Method to generate a new RTCP REMB message to cap the reported bitrate, but for more SSRCs
 * @param[in] packet The buffer data (MUST be at least 24 chars)
 * @param[in] len The message data length in bytes (MUST be 24)
 * @param[in] bitrate The bitrate to report (e.g., 128000)
 * @param[in] numssrc The number of SSRCs to include in the request
 * @returns The message data length in bytes, if successful, -1 on errors */
int janus_rtcp_remb_ssrcs(char *packet, int len, uint32_t bitrate, uint8_t numssrc);

/*! \brief Method to generate a new RTCP FIR message to request a key frame
 * @param[in] packet The buffer data (MUST be at least 20 chars)
 * @param[in] len The message data length in bytes (MUST be 20)
 * @param[in,out] seqnr The current FIR sequence number (will be incremented by the method)
 * @returns The message data length in bytes, if successful, -1 on errors */
int janus_rtcp_fir(char *packet, int len, int *seqnr);

/*! \brief Method to generate a new legacy RTCP FIR (RFC2032) message to request a key frame
 * \note This is actually identical to janus_rtcp_fir(), with the difference that we set 192 as packet type
 * @param[in] packet The buffer data (MUST be at least 20 chars)
 * @param[in] len The message data length in bytes (MUST be 20)
 * @param[in,out] seqnr The current FIR sequence number (will be incremented by the method)
 * @returns The message data length in bytes, if successful, -1 on errors */
int janus_rtcp_fir_legacy(char *packet, int len, int *seqnr);

/*! \brief Method to generate a new RTCP PLI message to request a key frame
 * @param[in] packet The buffer data (MUST be at least 12 chars)
 * @param[in] len The message data length in bytes (MUST be 12)
 * @returns The message data length in bytes, if successful, -1 on errors */
int janus_rtcp_pli(char *packet, int len);

/*! \brief Method to generate a new RTCP NACK message to report lost packets
 * @param[in] packet The buffer data (MUST be at least 16 chars)
 * @param[in] len The message data length in bytes (MUST be 16)
 * @param[in] nacks List of packets to NACK
 * @returns The message data length in bytes, if successful, -1 on errors */
int janus_rtcp_nacks(char *packet, int len, GSList *nacks);

/*! \brief Method to generate a new RTCP transport wide message to report reception stats
 * @param[in] packet The buffer data (MUST be at least 16 chars)
 * @param[in] len The message data length in bytes
 * @param[in] ssrc SSRC of the origin stream
 * @param[in] media SSRC of the destination stream
 * @param[in] feedback_packet_count Feedback paccket count
 * @param[in] transport_wide_cc_stats List of rtp packet reception stats
 * @returns The message data length in bytes, if successful, -1 on errors */
int janus_rtcp_transport_wide_cc_feedback(char *packet, size_t len, guint32 ssrc, guint32 media, guint8 feedback_packet_count, GQueue *transport_wide_cc_stats);

#endif