libavformat/rtmppkt.h

   1 /*
   2  * RTMP packet utilities
   3  * Copyright (c) 2009 Kostya 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 "avformat.h"
  26
  27 /** maximum possible number of different RTMP channels */
  28 #define RTMP_CHANNELS 64
  29
  30 /**
  31  * channels used to for RTMP packets with different purposes (i.e. data, network
  32  * control, remote procedure calls, etc.)
  33  */
  34 enum RTMPChannel {
  35     RTMP_NETWORK_CHANNEL = 2,   ///< channel for network-related messages (bandwidth report, ping, etc)
  36     RTMP_SYSTEM_CHANNEL,        ///< channel for sending server control messages
  37     RTMP_VIDEO_CHANNEL = 8,     ///< channel for video data
  38     RTMP_AUDIO_CHANNEL,         ///< channel for audio data
  39 };
  40
  41 /**
  42  * known RTMP packet types
  43  */
  44 typedef enum RTMPPacketType {
  45     RTMP_PT_CHUNK_SIZE   =  1,  ///< chunk size change
  46     RTMP_PT_BYTES_READ   =  3,  ///< number of bytes read
  47     RTMP_PT_PING,               ///< ping
  48     RTMP_PT_SERVER_BW,          ///< server bandwidth
  49     RTMP_PT_CLIENT_BW,          ///< client bandwidth
  50     RTMP_PT_AUDIO        =  8,  ///< audio packet
  51     RTMP_PT_VIDEO,              ///< video packet
  52     RTMP_PT_FLEX_STREAM  = 15,  ///< Flex shared stream
  53     RTMP_PT_FLEX_OBJECT,        ///< Flex shared object
  54     RTMP_PT_FLEX_MESSAGE,       ///< Flex shared message
  55     RTMP_PT_NOTIFY,             ///< some notification
  56     RTMP_PT_SHARED_OBJ,         ///< shared object
  57     RTMP_PT_INVOKE,             ///< invoke some stream action
  58     RTMP_PT_METADATA     = 22,  ///< FLV metadata
  59 } RTMPPacketType;
  60
  61 /**
  62  * possible RTMP packet header sizes
  63  */
  64 enum RTMPPacketSize {
  65     RTMP_PS_TWELVEBYTES = 0, ///< packet has 12-byte header
  66     RTMP_PS_EIGHTBYTES,      ///< packet has 8-byte header
  67     RTMP_PS_FOURBYTES,       ///< packet has 4-byte header
  68     RTMP_PS_ONEBYTE          ///< packet is really a next chunk of a packet
  69 };
  70
  71 /**
  72  * structure for holding RTMP packets
  73  */
  74 typedef struct RTMPPacket {
  75     uint8_t        channel_id; ///< RTMP channel ID (nothing to do with audio/video channels though)
  76     RTMPPacketType type;       ///< packet payload type
  77     uint32_t       timestamp;  ///< packet full timestamp or timestamp increment to the previous one in milliseconds (latter only for media packets)
  78     uint32_t       extra;      ///< probably an additional channel ID used during streaming data
  79     uint8_t        *data;      ///< packet payload
  80     int            data_size;  ///< packet payload size
  81 } RTMPPacket;
  82
  83 /**
  84  * Creates new RTMP packet with given attributes.
  85  *
  86  * @param pkt        packet
  87  * @param channel_id packet channel ID
  88  * @param type       packet type
  89  * @param timestamp  packet timestamp
  90  * @param size       packet size
  91  * @return zero on success, negative value otherwise
  92  */
  93 int ff_rtmp_packet_create(RTMPPacket *pkt, int channel_id, RTMPPacketType type,
  94                           int timestamp, int size);
  95
  96 /**
  97  * Frees RTMP packet.
  98  *
  99  * @param pkt packet
 100  */
 101 void ff_rtmp_packet_destroy(RTMPPacket *pkt);
 102
 103 /**
 104  * Reads RTMP packet sent by the server.
 105  *
 106  * @param h          reader context
 107  * @param p          packet
 108  * @param chunk_size current chunk size
 109  * @param prev_pkt   previously read packet headers for all channels
 110  *                   (may be needed for restoring incomplete packet header)
 111  * @return zero on success, negative value otherwise
 112  */
 113 int ff_rtmp_packet_read(URLContext *h, RTMPPacket *p,
 114                         int chunk_size, RTMPPacket *prev_pkt);
 115
 116 /**
 117  * Sends RTMP packet to the server.
 118  *
 119  * @param h          reader context
 120  * @param p          packet to send
 121  * @param chunk_size current chunk size
 122  * @param prev_pkt   previously sent packet headers for all channels
 123  *                   (may be used for packet header compressing)
 124  * @return zero on success, negative value otherwise
 125  */
 126 int ff_rtmp_packet_write(URLContext *h, RTMPPacket *p,
 127                          int chunk_size, RTMPPacket *prev_pkt);
 128
 129 /**
 130  * @defgroup amffuncs functions used to work with AMF format (which is also used in .flv)
 131  * @see amf_* funcs in libavformat/flvdec.c
 132  * @{
 133  */
 134
 135 /**
 136  * Calculates number of bytes taken by first AMF entry in data.
 137  *
 138  * @param data input data
 139  * @param data_end input buffer end
 140  * @return number of bytes used by first AMF entry
 141  */
 142 int ff_amf_tag_size(const uint8_t *data, const uint8_t *data_end);
 143
 144 /**
 145  * Retrieves value of given AMF object field in string form.
 146  *
 147  * @param data     AMF object data
 148  * @param data_end input buffer end
 149  * @param name     name of field to retrieve
 150  * @param dst      buffer for storing result
 151  * @param dst_size output buffer size
 152  * @return 0 if search and retrieval succeeded, negative value otherwise
 153  */
 154 int ff_amf_get_field_value(const uint8_t *data, const uint8_t *data_end,
 155                            const uint8_t *name, uint8_t *dst, int dst_size);
 156
 157 /**
 158  * Writes boolean value in AMF format to buffer.
 159  *
 160  * @param dst pointer to the input buffer (will be modified)
 161  * @param val value to write
 162  */
 163 void ff_amf_write_bool(uint8_t **dst, int val);
 164
 165 /**
 166  * Writes number in AMF format to buffer.
 167  *
 168  * @param dst pointer to the input buffer (will be modified)
 169  * @param num value to write
 170  */
 171 void ff_amf_write_number(uint8_t **dst, double num);
 172
 173 /**
 174  * Writes string in AMF format to buffer.
 175  *
 176  * @param dst pointer to the input buffer (will be modified)
 177  * @param str string to write
 178  */
 179 void ff_amf_write_string(uint8_t **dst, const char *str);
 180
 181 /**
 182  * Writes AMF NULL value to buffer.
 183  *
 184  * @param dst pointer to the input buffer (will be modified)
 185  */
 186 void ff_amf_write_null(uint8_t **dst);
 187
 188 /**
 189  * Writes marker for AMF object to buffer.
 190  *
 191  * @param dst pointer to the input buffer (will be modified)
 192  */
 193 void ff_amf_write_object_start(uint8_t **dst);
 194
 195 /**
 196  * Writes string used as field name in AMF object to buffer.
 197  *
 198  * @param dst pointer to the input buffer (will be modified)
 199  * @param str string to write
 200  */
 201 void ff_amf_write_field_name(uint8_t **dst, const char *str);
 202
 203 /**
 204  * Writes marker for end of AMF object to buffer.
 205  *
 206  * @param dst pointer to the input buffer (will be modified)
 207  */
 208 void ff_amf_write_object_end(uint8_t **dst);
 209
 210 /** @} */ // AMF funcs
 211
 212 #endif /* AVFORMAT_RTMPPKT_H */