2 * Common code for the RTP depacketization of MPEG-4 formats.
3 * Copyright (c) 2010 Fabrice Bellard
6 * This file is part of FFmpeg.
8 * FFmpeg 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.
13 * FFmpeg 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.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 * @brief MPEG4 / RTP Code
26 * @author Fabrice Bellard
27 * @author Romain Degez
30 #include "rtpdec_mpeg4.h"
32 #include "libavutil/avstring.h"
33 #include "libavcodec/get_bits.h"
36 /** Structure listing useful vars to parse RTP packet payload*/
47 /** mpeg 4 AU headers */
58 int au_headers_allocated;
60 int au_headers_length_bytes;
64 /* return the length and optionally the data */
65 static int hex_to_data(uint8_t *data, const char *p)
72 p += strspn(p, SPACE_CHARS);
75 c = toupper((unsigned char) *p++);
76 if (c >= '0' && c <= '9')
78 else if (c >= 'A' && c <= 'F')
99 /* All known fmtp parameters and the corresponding RTPAttrTypeEnum */
100 #define ATTR_NAME_TYPE_INT 0
101 #define ATTR_NAME_TYPE_STR 1
102 static const AttrNameMap attr_names[]=
104 { "SizeLength", ATTR_NAME_TYPE_INT,
105 offsetof(PayloadContext, sizelength) },
106 { "IndexLength", ATTR_NAME_TYPE_INT,
107 offsetof(PayloadContext, indexlength) },
108 { "IndexDeltaLength", ATTR_NAME_TYPE_INT,
109 offsetof(PayloadContext, indexdeltalength) },
110 { "profile-level-id", ATTR_NAME_TYPE_INT,
111 offsetof(PayloadContext, profile_level_id) },
112 { "StreamType", ATTR_NAME_TYPE_INT,
113 offsetof(PayloadContext, streamtype) },
114 { "mode", ATTR_NAME_TYPE_STR,
115 offsetof(PayloadContext, mode) },
119 static PayloadContext *new_context(void)
121 return av_mallocz(sizeof(PayloadContext));
124 static void free_context(PayloadContext * data)
127 for (i = 0; i < data->nb_au_headers; i++) {
128 /* according to rtp_parse_mp4_au, we treat multiple
129 * au headers as one, so nb_au_headers is always 1.
130 * loop anyway in case this changes.
131 * (note: changes done carelessly might lead to a double free)
133 av_free(&data->au_headers[i]);
139 static int parse_fmtp_config(AVCodecContext * codec, char *value)
141 /* decode the hexa encoded parameter */
142 int len = hex_to_data(NULL, value);
143 if (codec->extradata)
144 av_free(codec->extradata);
145 codec->extradata = av_mallocz(len + FF_INPUT_BUFFER_PADDING_SIZE);
146 if (!codec->extradata)
147 return AVERROR(ENOMEM);
148 codec->extradata_size = len;
149 hex_to_data(codec->extradata, value);
153 static int rtp_parse_mp4_au(PayloadContext *data, const uint8_t *buf)
155 int au_headers_length, au_header_size, i;
156 GetBitContext getbitcontext;
158 /* decode the first 2 bytes where the AUHeader sections are stored
160 au_headers_length = AV_RB16(buf);
162 if (au_headers_length > RTP_MAX_PACKET_LENGTH)
165 data->au_headers_length_bytes = (au_headers_length + 7) / 8;
167 /* skip AU headers length section (2 bytes) */
170 init_get_bits(&getbitcontext, buf, data->au_headers_length_bytes * 8);
172 /* XXX: Wrong if optionnal additional sections are present (cts, dts etc...) */
173 au_header_size = data->sizelength + data->indexlength;
174 if (au_header_size <= 0 || (au_headers_length % au_header_size != 0))
177 data->nb_au_headers = au_headers_length / au_header_size;
178 if (!data->au_headers || data->au_headers_allocated < data->nb_au_headers) {
179 av_free(data->au_headers);
180 data->au_headers = av_malloc(sizeof(struct AUHeaders) * data->nb_au_headers);
181 data->au_headers_allocated = data->nb_au_headers;
184 /* XXX: We handle multiple AU Section as only one (need to fix this for interleaving)
185 In my test, the FAAD decoder does not behave correctly when sending each AU one by one
186 but does when sending the whole as one big packet... */
187 data->au_headers[0].size = 0;
188 data->au_headers[0].index = 0;
189 for (i = 0; i < data->nb_au_headers; ++i) {
190 data->au_headers[0].size += get_bits_long(&getbitcontext, data->sizelength);
191 data->au_headers[0].index = get_bits_long(&getbitcontext, data->indexlength);
194 data->nb_au_headers = 1;
200 /* Follows RFC 3640 */
201 static int aac_parse_packet(AVFormatContext *ctx,
202 PayloadContext *data,
206 const uint8_t *buf, int len, int flags)
208 if (rtp_parse_mp4_au(data, buf))
211 buf += data->au_headers_length_bytes + 2;
212 len -= data->au_headers_length_bytes + 2;
214 /* XXX: Fixme we only handle the case where rtp_parse_mp4_au define
216 av_new_packet(pkt, data->au_headers[0].size);
217 memcpy(pkt->data, buf, data->au_headers[0].size);
219 pkt->stream_index = st->index;
223 static int parse_fmtp(AVStream *stream, PayloadContext *data,
224 char *attr, char *value)
226 AVCodecContext *codec = stream->codec;
229 if (!strcmp(attr, "config")) {
230 res = parse_fmtp_config(codec, value);
236 if (codec->codec_id == CODEC_ID_AAC) {
237 /* Looking for a known attribute */
238 for (i = 0; attr_names[i].str; ++i) {
239 if (!strcasecmp(attr, attr_names[i].str)) {
240 if (attr_names[i].type == ATTR_NAME_TYPE_INT) {
241 *(int *)((char *)data+
242 attr_names[i].offset) = atoi(value);
243 } else if (attr_names[i].type == ATTR_NAME_TYPE_STR)
244 *(char **)((char *)data+
245 attr_names[i].offset) = av_strdup(value);
252 static int parse_sdp_line(AVFormatContext *s, int st_index,
253 PayloadContext *data, const char *line)
257 if (av_strstart(line, "fmtp:", &p))
258 return ff_parse_fmtp(s->streams[st_index], data, p, parse_fmtp);
263 RTPDynamicProtocolHandler ff_mp4v_es_dynamic_handler = {
264 .enc_name = "MP4V-ES",
265 .codec_type = AVMEDIA_TYPE_VIDEO,
266 .codec_id = CODEC_ID_MPEG4,
267 .parse_sdp_a_line = parse_sdp_line,
273 RTPDynamicProtocolHandler ff_mpeg4_generic_dynamic_handler = {
274 .enc_name = "mpeg4-generic",
275 .codec_type = AVMEDIA_TYPE_AUDIO,
276 .codec_id = CODEC_ID_AAC,
277 .parse_sdp_a_line = parse_sdp_line,
279 .close = free_context,
280 .parse_packet = aac_parse_packet