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 FFmpeg.
7 *
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.
12 *
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.
17 *
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
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/attributes.h"
33#include "libavutil/avstring.h"
34#include "libavcodec/get_bits.h"
35
36/** Structure listing useful vars to parse RTP packet payload */
37struct PayloadContext {
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    uint8_t buf[RTP_MAX_PACKET_LENGTH];
63    int buf_pos, buf_size;
64};
65
66typedef struct {
67    const char *str;
68    uint16_t    type;
69    uint32_t    offset;
70} AttrNameMap;
71
72/* All known fmtp parameters and the corresponding RTPAttrTypeEnum */
73#define ATTR_NAME_TYPE_INT 0
74#define ATTR_NAME_TYPE_STR 1
75static const AttrNameMap attr_names[] = {
76    { "SizeLength",       ATTR_NAME_TYPE_INT,
77      offsetof(PayloadContext, sizelength) },
78    { "IndexLength",      ATTR_NAME_TYPE_INT,
79      offsetof(PayloadContext, indexlength) },
80    { "IndexDeltaLength", ATTR_NAME_TYPE_INT,
81      offsetof(PayloadContext, indexdeltalength) },
82    { "profile-level-id", ATTR_NAME_TYPE_INT,
83      offsetof(PayloadContext, profile_level_id) },
84    { "StreamType",       ATTR_NAME_TYPE_INT,
85      offsetof(PayloadContext, streamtype) },
86    { "mode",             ATTR_NAME_TYPE_STR,
87      offsetof(PayloadContext, mode) },
88    { NULL, -1, -1 },
89};
90
91static PayloadContext *new_context(void)
92{
93    return av_mallocz(sizeof(PayloadContext));
94}
95
96static void free_context(PayloadContext *data)
97{
98    av_free(data->au_headers);
99    av_free(data->mode);
100    av_free(data);
101}
102
103static int parse_fmtp_config(AVCodecContext *codec, char *value)
104{
105    /* decode the hexa encoded parameter */
106    int len = ff_hex_to_data(NULL, value);
107    av_free(codec->extradata);
108    if (ff_alloc_extradata(codec, len))
109        return AVERROR(ENOMEM);
110    ff_hex_to_data(codec->extradata, value);
111    return 0;
112}
113
114static int rtp_parse_mp4_au(PayloadContext *data, const uint8_t *buf, int len)
115{
116    int au_headers_length, au_header_size, i;
117    GetBitContext getbitcontext;
118
119    if (len < 2)
120        return AVERROR_INVALIDDATA;
121
122    /* decode the first 2 bytes where the AUHeader sections are stored
123       length in bits */
124    au_headers_length = AV_RB16(buf);
125
126    if (au_headers_length > RTP_MAX_PACKET_LENGTH)
127      return -1;
128
129    data->au_headers_length_bytes = (au_headers_length + 7) / 8;
130
131    /* skip AU headers length section (2 bytes) */
132    buf += 2;
133    len -= 2;
134
135    if (len < data->au_headers_length_bytes)
136        return AVERROR_INVALIDDATA;
137
138    init_get_bits(&getbitcontext, buf, data->au_headers_length_bytes * 8);
139
140    /* XXX: Wrong if optional additional sections are present (cts, dts etc...) */
141    au_header_size = data->sizelength + data->indexlength;
142    if (au_header_size <= 0 || (au_headers_length % au_header_size != 0))
143        return -1;
144
145    data->nb_au_headers = au_headers_length / au_header_size;
146    if (!data->au_headers || data->au_headers_allocated < data->nb_au_headers) {
147        av_free(data->au_headers);
148        data->au_headers = av_malloc(sizeof(struct AUHeaders) * data->nb_au_headers);
149        if (!data->au_headers)
150            return AVERROR(ENOMEM);
151        data->au_headers_allocated = data->nb_au_headers;
152    }
153
154    for (i = 0; i < data->nb_au_headers; ++i) {
155        data->au_headers[i].size  = get_bits_long(&getbitcontext, data->sizelength);
156        data->au_headers[i].index = get_bits_long(&getbitcontext, data->indexlength);
157    }
158
159    return 0;
160}
161
162
163/* Follows RFC 3640 */
164static int aac_parse_packet(AVFormatContext *ctx, PayloadContext *data,
165                            AVStream *st, AVPacket *pkt, uint32_t *timestamp,
166                            const uint8_t *buf, int len, uint16_t seq,
167                            int flags)
168{
169    int ret;
170
171    if (!buf) {
172        if (data->cur_au_index > data->nb_au_headers)
173            return AVERROR_INVALIDDATA;
174        if (data->buf_size - data->buf_pos < data->au_headers[data->cur_au_index].size)
175            return AVERROR_INVALIDDATA;
176        if ((ret = av_new_packet(pkt, data->au_headers[data->cur_au_index].size)) < 0)
177            return ret;
178        memcpy(pkt->data, &data->buf[data->buf_pos], data->au_headers[data->cur_au_index].size);
179        data->buf_pos += data->au_headers[data->cur_au_index].size;
180        pkt->stream_index = st->index;
181        data->cur_au_index++;
182        return data->cur_au_index < data->nb_au_headers;
183    }
184
185    if (rtp_parse_mp4_au(data, buf, len))
186        return -1;
187
188    buf += data->au_headers_length_bytes + 2;
189    len -= data->au_headers_length_bytes + 2;
190
191    if (len < data->au_headers[0].size)
192        return AVERROR_INVALIDDATA;
193    if ((ret = av_new_packet(pkt, data->au_headers[0].size)) < 0)
194        return ret;
195    memcpy(pkt->data, buf, data->au_headers[0].size);
196    len -= data->au_headers[0].size;
197    buf += data->au_headers[0].size;
198    pkt->stream_index = st->index;
199
200    if (len > 0 && data->nb_au_headers > 1) {
201        data->buf_size = FFMIN(len, sizeof(data->buf));
202        memcpy(data->buf, buf, data->buf_size);
203        data->cur_au_index = 1;
204        data->buf_pos = 0;
205        return 1;
206    }
207
208    return 0;
209}
210
211static int parse_fmtp(AVFormatContext *s,
212                      AVStream *stream, PayloadContext *data,
213                      char *attr, char *value)
214{
215    AVCodecContext *codec = stream->codec;
216    int res, i;
217
218    if (!strcmp(attr, "config")) {
219        res = parse_fmtp_config(codec, value);
220
221        if (res < 0)
222            return res;
223    }
224
225    if (codec->codec_id == AV_CODEC_ID_AAC) {
226        /* Looking for a known attribute */
227        for (i = 0; attr_names[i].str; ++i) {
228            if (!av_strcasecmp(attr, attr_names[i].str)) {
229                if (attr_names[i].type == ATTR_NAME_TYPE_INT) {
230                    *(int *)((char *)data+
231                        attr_names[i].offset) = atoi(value);
232                } else if (attr_names[i].type == ATTR_NAME_TYPE_STR)
233                    *(char **)((char *)data+
234                        attr_names[i].offset) = av_strdup(value);
235            }
236        }
237    }
238    return 0;
239}
240
241static int parse_sdp_line(AVFormatContext *s, int st_index,
242                          PayloadContext *data, const char *line)
243{
244    const char *p;
245
246    if (st_index < 0)
247        return 0;
248
249    if (av_strstart(line, "fmtp:", &p))
250        return ff_parse_fmtp(s, s->streams[st_index], data, p, parse_fmtp);
251
252    return 0;
253}
254
255static av_cold int init_video(AVFormatContext *s, int st_index,
256                              PayloadContext *data)
257{
258    if (st_index < 0)
259        return 0;
260    s->streams[st_index]->need_parsing = AVSTREAM_PARSE_FULL;
261    return 0;
262}
263
264RTPDynamicProtocolHandler ff_mp4v_es_dynamic_handler = {
265    .enc_name           = "MP4V-ES",
266    .codec_type         = AVMEDIA_TYPE_VIDEO,
267    .codec_id           = AV_CODEC_ID_MPEG4,
268    .init               = init_video,
269    .parse_sdp_a_line   = parse_sdp_line,
270};
271
272RTPDynamicProtocolHandler ff_mpeg4_generic_dynamic_handler = {
273    .enc_name           = "mpeg4-generic",
274    .codec_type         = AVMEDIA_TYPE_AUDIO,
275    .codec_id           = AV_CODEC_ID_AAC,
276    .parse_sdp_a_line   = parse_sdp_line,
277    .alloc              = new_context,
278    .free               = free_context,
279    .parse_packet       = aac_parse_packet
280};
281