FFmpeg: libavformat/rtmppkt.h Source File

FFmpeg
rtmppkt.h
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1 /*
2  * RTMP packet utilities
3  * Copyright (c) 2009 Konstantin Shishkov
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #ifndef AVFORMAT_RTMPPKT_H
23 #define AVFORMAT_RTMPPKT_H
24 
25 #include "libavcodec/bytestream.h"
26 #include "avformat.h"
27 #include "url.h"
28 
29 /** maximum possible number of different RTMP channels */
30  #define RTMP_CHANNELS 65599
31 
32 /**
33  * channels used to for RTMP packets with different purposes (i.e. data, network
34  * control, remote procedure calls, etc.)
35  */
36  enum RTMPChannel {
37   RTMP_NETWORK_CHANNEL = 2, ///< channel for network-related messages (bandwidth report, ping, etc)
38   RTMP_SYSTEM_CHANNEL, ///< channel for sending server control messages
39   RTMP_AUDIO_CHANNEL, ///< channel for audio data
40   RTMP_VIDEO_CHANNEL = 6, ///< channel for video data
41   RTMP_SOURCE_CHANNEL = 8, ///< channel for a/v invokes
42 };
43 
44 /**
45  * known RTMP packet types
46  */
47  typedef enum RTMPPacketType {
48   RTMP_PT_CHUNK_SIZE = 1, ///< chunk size change
49   RTMP_PT_BYTES_READ = 3, ///< number of bytes read
50   RTMP_PT_PING, ///< ping
51   RTMP_PT_SERVER_BW, ///< server bandwidth
52   RTMP_PT_CLIENT_BW, ///< client bandwidth
53   RTMP_PT_AUDIO = 8, ///< audio packet
54   RTMP_PT_VIDEO, ///< video packet
55   RTMP_PT_FLEX_STREAM = 15, ///< Flex shared stream
56   RTMP_PT_FLEX_OBJECT, ///< Flex shared object
57   RTMP_PT_FLEX_MESSAGE, ///< Flex shared message
58   RTMP_PT_NOTIFY, ///< some notification
59   RTMP_PT_SHARED_OBJ, ///< shared object
60   RTMP_PT_INVOKE, ///< invoke some stream action
61   RTMP_PT_METADATA = 22, ///< FLV metadata
62 } RTMPPacketType;
63 
64 /**
65  * possible RTMP packet header sizes
66  */
67  enum RTMPPacketSize {
68   RTMP_PS_TWELVEBYTES = 0, ///< packet has 12-byte header
69   RTMP_PS_EIGHTBYTES, ///< packet has 8-byte header
70   RTMP_PS_FOURBYTES, ///< packet has 4-byte header
71   RTMP_PS_ONEBYTE ///< packet is really a next chunk of a packet
72 };
73 
74 /**
75  * structure for holding RTMP packets
76  */
77  typedef struct RTMPPacket {
78   int channel_id; ///< RTMP channel ID (nothing to do with audio/video channels though)
79   RTMPPacketType type; ///< packet payload type
80   uint32_t timestamp; ///< packet full timestamp
81   uint32_t ts_delta; ///< timestamp increment to the previous one in milliseconds (latter only for media packets)
82   uint32_t extra; ///< probably an additional channel ID used during streaming data
83   uint8_t *data; ///< packet payload
84   int size; ///< packet payload size
85   int offset; ///< amount of data read so far
86   int read; ///< amount read, including headers
87 } RTMPPacket;
88 
89 /**
90  * Create new RTMP packet with given attributes.
91  *
92  * @param pkt packet
93  * @param channel_id packet channel ID
94  * @param type packet type
95  * @param timestamp packet timestamp
96  * @param size packet size
97  * @return zero on success, negative value otherwise
98  */
99 int ff_rtmp_packet_create(RTMPPacket *pkt, int channel_id, RTMPPacketType type,
100  int timestamp, int size);
101 
102 /**
103  * Free RTMP packet.
104  *
105  * @param pkt packet
106  */
107 void ff_rtmp_packet_destroy(RTMPPacket *pkt);
108 
109 /**
110  * Read RTMP packet sent by the server.
111  *
112  * @param h reader context
113  * @param p packet
114  * @param chunk_size current chunk size
115  * @param prev_pkt previously read packet headers for all channels
116  * (may be needed for restoring incomplete packet header)
117  * @param nb_prev_pkt number of allocated elements in prev_pkt
118  * @return number of bytes read on success, negative value otherwise
119  */
120 int ff_rtmp_packet_read(URLContext *h, RTMPPacket *p,
121  int chunk_size, RTMPPacket **prev_pkt,
122  int *nb_prev_pkt);
123 /**
124  * Read internal RTMP packet sent by the server.
125  *
126  * @param h reader context
127  * @param p packet
128  * @param chunk_size current chunk size
129  * @param prev_pkt previously read packet headers for all channels
130  * (may be needed for restoring incomplete packet header)
131  * @param nb_prev_pkt number of allocated elements in prev_pkt
132  * @param c the first byte already read
133  * @return number of bytes read on success, negative value otherwise
134  */
135 int ff_rtmp_packet_read_internal(URLContext *h, RTMPPacket *p, int chunk_size,
136  RTMPPacket **prev_pkt, int *nb_prev_pkt,
137  uint8_t c);
138 
139 /**
140  * Send RTMP packet to the server.
141  *
142  * @param h reader context
143  * @param p packet to send
144  * @param chunk_size current chunk size
145  * @param prev_pkt previously sent packet headers for all channels
146  * (may be used for packet header compressing)
147  * @param nb_prev_pkt number of allocated elements in prev_pkt
148  * @return number of bytes written on success, negative value otherwise
149  */
150 int ff_rtmp_packet_write(URLContext *h, RTMPPacket *p,
151  int chunk_size, RTMPPacket **prev_pkt,
152  int *nb_prev_pkt);
153 
154 /**
155  * Print information and contents of RTMP packet.
156  *
157  * @param ctx output context
158  * @param p packet to dump
159  */
160 void ff_rtmp_packet_dump(void *ctx, RTMPPacket *p);
161 
162 /**
163  * Enlarge the prev_pkt array to fit the given channel
164  *
165  * @param prev_pkt array with previously sent packet headers
166  * @param nb_prev_pkt number of allocated elements in prev_pkt
167  * @param channel the channel number that needs to be allocated
168  */
169 int ff_rtmp_check_alloc_array(RTMPPacket **prev_pkt, int *nb_prev_pkt,
170  int channel);
171 
172 /**
173  * @name Functions used to work with the AMF format (which is also used in .flv)
174  * @see amf_* funcs in libavformat/flvdec.c
175  * @{
176  */
177 
178 /**
179  * Calculate number of bytes taken by first AMF entry in data.
180  *
181  * @param data input data
182  * @param data_end input buffer end
183  * @return number of bytes used by first AMF entry
184  */
185 int ff_amf_tag_size(const uint8_t *data, const uint8_t *data_end);
186 
187 /**
188  * Retrieve value of given AMF object field in string form.
189  *
190  * @param data AMF object data
191  * @param data_end input buffer end
192  * @param name name of field to retrieve
193  * @param dst buffer for storing result
194  * @param dst_size output buffer size
195  * @return 0 if search and retrieval succeeded, negative value otherwise
196  */
197 int ff_amf_get_field_value(const uint8_t *data, const uint8_t *data_end,
198  const uint8_t *name, uint8_t *dst, int dst_size);
199 
200 /**
201  * Write boolean value in AMF format to buffer.
202  *
203  * @param dst pointer to the input buffer (will be modified)
204  * @param val value to write
205  */
206 void ff_amf_write_bool(uint8_t **dst, int val);
207 
208 /**
209  * Write number in AMF format to buffer.
210  *
211  * @param dst pointer to the input buffer (will be modified)
212  * @param num value to write
213  */
214 void ff_amf_write_number(uint8_t **dst, double num);
215 
216 /**
217  * Write string in AMF format to buffer.
218  *
219  * @param dst pointer to the input buffer (will be modified)
220  * @param str string to write
221  */
222 void ff_amf_write_string(uint8_t **dst, const char *str);
223 
224 /**
225  * Write a string consisting of two parts in AMF format to a buffer.
226  *
227  * @param dst pointer to the input buffer (will be modified)
228  * @param str1 first string to write, may be null
229  * @param str2 second string to write, may be null
230  */
231 void ff_amf_write_string2(uint8_t **dst, const char *str1, const char *str2);
232 
233 /**
234  * Write AMF NULL value to buffer.
235  *
236  * @param dst pointer to the input buffer (will be modified)
237  */
238 void ff_amf_write_null(uint8_t **dst);
239 
240 /**
241  * Write marker for AMF object to buffer.
242  *
243  * @param dst pointer to the input buffer (will be modified)
244  */
245 void ff_amf_write_object_start(uint8_t **dst);
246 
247 /**
248  * Write string used as field name in AMF object to buffer.
249  *
250  * @param dst pointer to the input buffer (will be modified)
251  * @param str string to write
252  */
253 void ff_amf_write_field_name(uint8_t **dst, const char *str);
254 
255 /**
256  * Write marker for end of AMF object to buffer.
257  *
258  * @param dst pointer to the input buffer (will be modified)
259  */
260 void ff_amf_write_object_end(uint8_t **dst);
261 
262 /**
263  * Read AMF boolean value.
264  *
265  *@param[in,out] gbc GetByteContext initialized with AMF-formatted data
266  *@param[out] val 0 or 1
267  *@return 0 on success or an AVERROR code on failure
268 */
269 int ff_amf_read_bool(GetByteContext *gbc, int *val);
270 
271 /**
272  * Read AMF number value.
273  *
274  *@param[in,out] gbc GetByteContext initialized with AMF-formatted data
275  *@param[out] val read value
276  *@return 0 on success or an AVERROR code on failure
277 */
278 int ff_amf_read_number(GetByteContext *gbc, double *val);
279 
280 /**
281  * Read AMF string value.
282  *
283  * Appends a trailing null byte to output string in order to
284  * ease later parsing.
285  *
286  *@param[in,out] gbc GetByteContext initialized with AMF-formatted data
287  *@param[out] str read string
288  *@param[in] strsize buffer size available to store the read string
289  *@param[out] length read string length
290  *@return 0 on success or an AVERROR code on failure
291 */
292 int ff_amf_read_string(GetByteContext *gbc, uint8_t *str,
293  int strsize, int *length);
294 
295 /**
296  * Read AMF NULL value.
297  *
298  *@param[in,out] gbc GetByteContext initialized with AMF-formatted data
299  *@return 0 on success or an AVERROR code on failure
300 */
301 int ff_amf_read_null(GetByteContext *gbc);
302 
303 /**
304  * Match AMF string with a NULL-terminated string.
305  *
306  * @return 0 if the strings do not match.
307  */
308 
309 int ff_amf_match_string(const uint8_t *data, int size, const char *str);
310 
311 /** @} */ // AMF funcs
312 
313 #endif /* AVFORMAT_RTMPPKT_H */
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