1/** 2 * Common code for the RTP depacketization of MPEG-4 formats. 3 * Copyright (c) 2010 Fabrice Bellard 4 * Romain Degez 5 * 6 * This file is part of Libav. 7 * 8 * Libav is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU Lesser General Public 10 * License as published by the Free Software Foundation; either 11 * version 2.1 of the License, or (at your option) any later version. 12 * 13 * Libav is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 16 * Lesser General Public License for more details. 17 * 18 * You should have received a copy of the GNU Lesser General Public 19 * License along with Libav; if not, write to the Free Software 20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 21 */ 22 23/** 24 * @file 25 * @brief MPEG4 / RTP Code 26 * @author Fabrice Bellard 27 * @author Romain Degez 28 */ 29 30#include "rtpdec_formats.h" 31#include "internal.h" 32#include "libavutil/avstring.h" 33#include "libavcodec/get_bits.h" 34 35/** Structure listing useful vars to parse RTP packet payload*/ 36struct PayloadContext 37{ 38 int sizelength; 39 int indexlength; 40 int indexdeltalength; 41 int profile_level_id; 42 int streamtype; 43 int objecttype; 44 char *mode; 45 46 /** mpeg 4 AU headers */ 47 struct AUHeaders { 48 int size; 49 int index; 50 int cts_flag; 51 int cts; 52 int dts_flag; 53 int dts; 54 int rap_flag; 55 int streamstate; 56 } *au_headers; 57 int au_headers_allocated; 58 int nb_au_headers; 59 int au_headers_length_bytes; 60 int cur_au_index; 61}; 62 63typedef struct { 64 const char *str; 65 uint16_t type; 66 uint32_t offset; 67} AttrNameMap; 68 69/* All known fmtp parameters and the corresponding RTPAttrTypeEnum */ 70#define ATTR_NAME_TYPE_INT 0 71#define ATTR_NAME_TYPE_STR 1 72static const AttrNameMap attr_names[]= 73{ 74 { "SizeLength", ATTR_NAME_TYPE_INT, 75 offsetof(PayloadContext, sizelength) }, 76 { "IndexLength", ATTR_NAME_TYPE_INT, 77 offsetof(PayloadContext, indexlength) }, 78 { "IndexDeltaLength", ATTR_NAME_TYPE_INT, 79 offsetof(PayloadContext, indexdeltalength) }, 80 { "profile-level-id", ATTR_NAME_TYPE_INT, 81 offsetof(PayloadContext, profile_level_id) }, 82 { "StreamType", ATTR_NAME_TYPE_INT, 83 offsetof(PayloadContext, streamtype) }, 84 { "mode", ATTR_NAME_TYPE_STR, 85 offsetof(PayloadContext, mode) }, 86 { NULL, -1, -1 }, 87}; 88 89static PayloadContext *new_context(void) 90{ 91 return av_mallocz(sizeof(PayloadContext)); 92} 93 94static void free_context(PayloadContext * data) 95{ 96 int i; 97 for (i = 0; i < data->nb_au_headers; i++) { 98 /* according to rtp_parse_mp4_au, we treat multiple 99 * au headers as one, so nb_au_headers is always 1. 100 * loop anyway in case this changes. 101 * (note: changes done carelessly might lead to a double free) 102 */ 103 av_free(&data->au_headers[i]); 104 } 105 av_free(data->mode); 106 av_free(data); 107} 108 109static int parse_fmtp_config(AVCodecContext * codec, char *value) 110{ 111 /* decode the hexa encoded parameter */ 112 int len = ff_hex_to_data(NULL, value); 113 av_free(codec->extradata); 114 codec->extradata = av_mallocz(len + FF_INPUT_BUFFER_PADDING_SIZE); 115 if (!codec->extradata) 116 return AVERROR(ENOMEM); 117 codec->extradata_size = len; 118 ff_hex_to_data(codec->extradata, value); 119 return 0; 120} 121 122static int rtp_parse_mp4_au(PayloadContext *data, const uint8_t *buf) 123{ 124 int au_headers_length, au_header_size, i; 125 GetBitContext getbitcontext; 126 127 /* decode the first 2 bytes where the AUHeader sections are stored 128 length in bits */ 129 au_headers_length = AV_RB16(buf); 130 131 if (au_headers_length > RTP_MAX_PACKET_LENGTH) 132 return -1; 133 134 data->au_headers_length_bytes = (au_headers_length + 7) / 8; 135 136 /* skip AU headers length section (2 bytes) */ 137 buf += 2; 138 139 init_get_bits(&getbitcontext, buf, data->au_headers_length_bytes * 8); 140 141 /* XXX: Wrong if optionnal additional sections are present (cts, dts etc...) */ 142 au_header_size = data->sizelength + data->indexlength; 143 if (au_header_size <= 0 || (au_headers_length % au_header_size != 0)) 144 return -1; 145 146 data->nb_au_headers = au_headers_length / au_header_size; 147 if (!data->au_headers || data->au_headers_allocated < data->nb_au_headers) { 148 av_free(data->au_headers); 149 data->au_headers = av_malloc(sizeof(struct AUHeaders) * data->nb_au_headers); 150 data->au_headers_allocated = data->nb_au_headers; 151 } 152 153 /* XXX: We handle multiple AU Section as only one (need to fix this for interleaving) 154 In my test, the FAAD decoder does not behave correctly when sending each AU one by one 155 but does when sending the whole as one big packet... */ 156 data->au_headers[0].size = 0; 157 data->au_headers[0].index = 0; 158 for (i = 0; i < data->nb_au_headers; ++i) { 159 data->au_headers[0].size += get_bits_long(&getbitcontext, data->sizelength); 160 data->au_headers[0].index = get_bits_long(&getbitcontext, data->indexlength); 161 } 162 163 data->nb_au_headers = 1; 164 165 return 0; 166} 167 168 169/* Follows RFC 3640 */ 170static int aac_parse_packet(AVFormatContext *ctx, 171 PayloadContext *data, 172 AVStream *st, 173 AVPacket *pkt, 174 uint32_t *timestamp, 175 const uint8_t *buf, int len, int flags) 176{ 177 if (rtp_parse_mp4_au(data, buf)) 178 return -1; 179 180 buf += data->au_headers_length_bytes + 2; 181 len -= data->au_headers_length_bytes + 2; 182 183 /* XXX: Fixme we only handle the case where rtp_parse_mp4_au define 184 one au_header */ 185 av_new_packet(pkt, data->au_headers[0].size); 186 memcpy(pkt->data, buf, data->au_headers[0].size); 187 188 pkt->stream_index = st->index; 189 return 0; 190} 191 192static int parse_fmtp(AVStream *stream, PayloadContext *data, 193 char *attr, char *value) 194{ 195 AVCodecContext *codec = stream->codec; 196 int res, i; 197 198 if (!strcmp(attr, "config")) { 199 res = parse_fmtp_config(codec, value); 200 201 if (res < 0) 202 return res; 203 } 204 205 if (codec->codec_id == CODEC_ID_AAC) { 206 /* Looking for a known attribute */ 207 for (i = 0; attr_names[i].str; ++i) { 208 if (!av_strcasecmp(attr, attr_names[i].str)) { 209 if (attr_names[i].type == ATTR_NAME_TYPE_INT) { 210 *(int *)((char *)data+ 211 attr_names[i].offset) = atoi(value); 212 } else if (attr_names[i].type == ATTR_NAME_TYPE_STR) 213 *(char **)((char *)data+ 214 attr_names[i].offset) = av_strdup(value); 215 } 216 } 217 } 218 return 0; 219} 220 221static int parse_sdp_line(AVFormatContext *s, int st_index, 222 PayloadContext *data, const char *line) 223{ 224 const char *p; 225 226 if (av_strstart(line, "fmtp:", &p)) 227 return ff_parse_fmtp(s->streams[st_index], data, p, parse_fmtp); 228 229 return 0; 230} 231 232RTPDynamicProtocolHandler ff_mp4v_es_dynamic_handler = { 233 .enc_name = "MP4V-ES", 234 .codec_type = AVMEDIA_TYPE_VIDEO, 235 .codec_id = CODEC_ID_MPEG4, 236 .parse_sdp_a_line = parse_sdp_line, 237}; 238 239RTPDynamicProtocolHandler ff_mpeg4_generic_dynamic_handler = { 240 .enc_name = "mpeg4-generic", 241 .codec_type = AVMEDIA_TYPE_AUDIO, 242 .codec_id = CODEC_ID_AAC, 243 .parse_sdp_a_line = parse_sdp_line, 244 .alloc = new_context, 245 .free = free_context, 246 .parse_packet = aac_parse_packet 247}; 248