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 MPEG-4 / 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#define MAX_AAC_HBR_FRAME_SIZE 8191
37
38/** Structure listing useful vars to parse RTP packet payload */
39struct PayloadContext {
40    int sizelength;
41    int indexlength;
42    int indexdeltalength;
43    int profile_level_id;
44    int streamtype;
45    int objecttype;
46    char *mode;
47
48    /** mpeg 4 AU headers */
49    struct AUHeaders {
50        int size;
51        int index;
52        int cts_flag;
53        int cts;
54        int dts_flag;
55        int dts;
56        int rap_flag;
57        int streamstate;
58    } *au_headers;
59    int au_headers_allocated;
60    int nb_au_headers;
61    int au_headers_length_bytes;
62    int cur_au_index;
63
64    uint8_t buf[FFMAX(RTP_MAX_PACKET_LENGTH, MAX_AAC_HBR_FRAME_SIZE)];
65    int buf_pos, buf_size;
66    uint32_t timestamp;
67};
68
69typedef struct AttrNameMap {
70    const char *str;
71    uint16_t    type;
72    uint32_t    offset;
73
74    /** Range for integer values */
75    struct Range {
76        int min;
77        int max;
78    } range;
79} AttrNameMap;
80
81/* All known fmtp parameters and the corresponding RTPAttrTypeEnum */
82#define ATTR_NAME_TYPE_INT 0
83#define ATTR_NAME_TYPE_STR 1
84static const AttrNameMap attr_names[] = {
85    { "SizeLength",       ATTR_NAME_TYPE_INT,
86      offsetof(PayloadContext, sizelength),
87      {0, 32} }, // SizeLength number of bits used to encode AU-size integer value
88    { "IndexLength",      ATTR_NAME_TYPE_INT,
89      offsetof(PayloadContext, indexlength),
90      {0, 32} }, // IndexLength number of bits used to encode AU-Index integer value
91    { "IndexDeltaLength", ATTR_NAME_TYPE_INT,
92      offsetof(PayloadContext, indexdeltalength),
93      {0, 32} }, // IndexDeltaLength number of bits to encode AU-Index-delta integer value
94    { "profile-level-id", ATTR_NAME_TYPE_INT,
95      offsetof(PayloadContext, profile_level_id),
96      {INT32_MIN, INT32_MAX} }, // It differs depending on StreamType
97    { "StreamType",       ATTR_NAME_TYPE_INT,
98      offsetof(PayloadContext, streamtype),
99      {0x00, 0x3F} }, // Values from ISO/IEC 14496-1, 'StreamType Values' table
100    { "mode",             ATTR_NAME_TYPE_STR,
101      offsetof(PayloadContext, mode),
102       {0} },
103    { NULL, -1, -1, {0} },
104};
105
106static void close_context(PayloadContext *data)
107{
108    av_freep(&data->au_headers);
109    av_freep(&data->mode);
110}
111
112static int parse_fmtp_config(AVCodecParameters *par, const char *value)
113{
114    /* decode the hexa encoded parameter */
115    int len = ff_hex_to_data(NULL, value), ret;
116
117    if ((ret = ff_alloc_extradata(par, len)) < 0)
118        return ret;
119    ff_hex_to_data(par->extradata, value);
120    return 0;
121}
122
123static int rtp_parse_mp4_au(PayloadContext *data, const uint8_t *buf, int len)
124{
125    int au_headers_length, au_header_size, i;
126    GetBitContext getbitcontext;
127    int ret;
128
129    if (len < 2)
130        return AVERROR_INVALIDDATA;
131
132    /* decode the first 2 bytes where the AUHeader sections are stored
133       length in bits */
134    au_headers_length = AV_RB16(buf);
135
136    if (au_headers_length > RTP_MAX_PACKET_LENGTH)
137      return -1;
138
139    data->au_headers_length_bytes = (au_headers_length + 7) / 8;
140
141    /* skip AU headers length section (2 bytes) */
142    buf += 2;
143    len -= 2;
144
145    if (len < data->au_headers_length_bytes)
146        return AVERROR_INVALIDDATA;
147
148    ret = init_get_bits(&getbitcontext, buf, data->au_headers_length_bytes * 8);
149    if (ret < 0)
150        return ret;
151
152    /* XXX: Wrong if optional additional sections are present (cts, dts etc...) */
153    au_header_size = data->sizelength + data->indexlength;
154    if (au_header_size <= 0 || (au_headers_length % au_header_size != 0))
155        return -1;
156
157    data->nb_au_headers = au_headers_length / au_header_size;
158    if (!data->au_headers || data->au_headers_allocated < data->nb_au_headers) {
159        av_free(data->au_headers);
160        data->au_headers = av_malloc(sizeof(struct AUHeaders) * data->nb_au_headers);
161        if (!data->au_headers)
162            return AVERROR(ENOMEM);
163        data->au_headers_allocated = data->nb_au_headers;
164    }
165
166    for (i = 0; i < data->nb_au_headers; ++i) {
167        data->au_headers[i].size  = get_bits_long(&getbitcontext, data->sizelength);
168        data->au_headers[i].index = get_bits_long(&getbitcontext, data->indexlength);
169    }
170
171    return 0;
172}
173
174
175/* Follows RFC 3640 */
176static int aac_parse_packet(AVFormatContext *ctx, PayloadContext *data,
177                            AVStream *st, AVPacket *pkt, uint32_t *timestamp,
178                            const uint8_t *buf, int len, uint16_t seq,
179                            int flags)
180{
181    int ret;
182
183
184    if (!buf) {
185        if (data->cur_au_index > data->nb_au_headers) {
186            av_log(ctx, AV_LOG_ERROR, "Invalid parser state\n");
187            return AVERROR_INVALIDDATA;
188        }
189        if (data->buf_size - data->buf_pos < data->au_headers[data->cur_au_index].size) {
190            av_log(ctx, AV_LOG_ERROR, "Invalid AU size\n");
191            return AVERROR_INVALIDDATA;
192        }
193        if ((ret = av_new_packet(pkt, data->au_headers[data->cur_au_index].size)) < 0) {
194            av_log(ctx, AV_LOG_ERROR, "Out of memory\n");
195            return ret;
196        }
197        memcpy(pkt->data, &data->buf[data->buf_pos], data->au_headers[data->cur_au_index].size);
198        data->buf_pos += data->au_headers[data->cur_au_index].size;
199        pkt->stream_index = st->index;
200        data->cur_au_index++;
201
202        if (data->cur_au_index == data->nb_au_headers) {
203            data->buf_pos = 0;
204            return 0;
205        }
206
207        return 1;
208    }
209
210    if (rtp_parse_mp4_au(data, buf, len)) {
211        av_log(ctx, AV_LOG_ERROR, "Error parsing AU headers\n");
212        return -1;
213    }
214
215    buf += data->au_headers_length_bytes + 2;
216    len -= data->au_headers_length_bytes + 2;
217    if (data->nb_au_headers == 1 && len < data->au_headers[0].size) {
218        /* Packet is fragmented */
219
220        if (!data->buf_pos) {
221            if (data->au_headers[0].size > MAX_AAC_HBR_FRAME_SIZE) {
222                av_log(ctx, AV_LOG_ERROR, "Invalid AU size\n");
223                return AVERROR_INVALIDDATA;
224            }
225
226            data->buf_size = data->au_headers[0].size;
227            data->timestamp = *timestamp;
228        }
229
230        if (data->timestamp != *timestamp ||
231            data->au_headers[0].size != data->buf_size ||
232            data->buf_pos + len > MAX_AAC_HBR_FRAME_SIZE) {
233            data->buf_pos = 0;
234            data->buf_size = 0;
235            av_log(ctx, AV_LOG_ERROR, "Invalid packet received\n");
236            return AVERROR_INVALIDDATA;
237        }
238
239        memcpy(&data->buf[data->buf_pos], buf, len);
240        data->buf_pos += len;
241
242        if (!(flags & RTP_FLAG_MARKER))
243            return AVERROR(EAGAIN);
244
245        if (data->buf_pos != data->buf_size) {
246            data->buf_pos = 0;
247            av_log(ctx, AV_LOG_ERROR, "Missed some packets, discarding frame\n");
248            return AVERROR_INVALIDDATA;
249        }
250
251        data->buf_pos = 0;
252        ret = av_new_packet(pkt, data->buf_size);
253        if (ret < 0) {
254            av_log(ctx, AV_LOG_ERROR, "Out of memory\n");
255            return ret;
256        }
257        pkt->stream_index = st->index;
258
259        memcpy(pkt->data, data->buf, data->buf_size);
260
261        return 0;
262    }
263
264    if (len < data->au_headers[0].size) {
265        av_log(ctx, AV_LOG_ERROR, "First AU larger than packet size\n");
266        return AVERROR_INVALIDDATA;
267    }
268    if ((ret = av_new_packet(pkt, data->au_headers[0].size)) < 0) {
269        av_log(ctx, AV_LOG_ERROR, "Out of memory\n");
270        return ret;
271    }
272    memcpy(pkt->data, buf, data->au_headers[0].size);
273    len -= data->au_headers[0].size;
274    buf += data->au_headers[0].size;
275    pkt->stream_index = st->index;
276
277    if (len > 0 && data->nb_au_headers > 1) {
278        data->buf_size = FFMIN(len, sizeof(data->buf));
279        memcpy(data->buf, buf, data->buf_size);
280        data->cur_au_index = 1;
281        data->buf_pos = 0;
282        return 1;
283    }
284
285    return 0;
286}
287
288static int parse_fmtp(AVFormatContext *s,
289                      AVStream *stream, PayloadContext *data,
290                      const char *attr, const char *value)
291{
292    AVCodecParameters *par = stream->codecpar;
293    int res, i;
294
295    if (!strcmp(attr, "config")) {
296        res = parse_fmtp_config(par, value);
297
298        if (res < 0)
299            return res;
300    }
301
302    if (par->codec_id == AV_CODEC_ID_AAC) {
303        /* Looking for a known attribute */
304        for (i = 0; attr_names[i].str; ++i) {
305            if (!av_strcasecmp(attr, attr_names[i].str)) {
306                if (attr_names[i].type == ATTR_NAME_TYPE_INT) {
307                    char *end_ptr = NULL;
308                    long long int val = strtoll(value, &end_ptr, 10);
309                    if (end_ptr == value || end_ptr[0] != '\0') {
310                        av_log(s, AV_LOG_ERROR,
311                               "The %s field value is not a valid number: %s\n",
312                               attr, value);
313                        return AVERROR_INVALIDDATA;
314                    }
315                    if (val < attr_names[i].range.min ||
316                        val > attr_names[i].range.max) {
317                        av_log(s, AV_LOG_ERROR,
318                            "fmtp field %s should be in range [%d,%d] (provided value: %lld)",
319                            attr, attr_names[i].range.min, attr_names[i].range.max, val);
320                        return  AVERROR_INVALIDDATA;
321                    }
322
323                    *(int *)((char *)data+
324                        attr_names[i].offset) = (int) val;
325                } else if (attr_names[i].type == ATTR_NAME_TYPE_STR) {
326                    char *val = av_strdup(value);
327                    if (!val)
328                        return AVERROR(ENOMEM);
329                    *(char **)((char *)data+
330                        attr_names[i].offset) = val;
331                }
332            }
333        }
334    }
335    return 0;
336}
337
338static int parse_sdp_line(AVFormatContext *s, int st_index,
339                          PayloadContext *data, const char *line)
340{
341    const char *p;
342
343    if (st_index < 0)
344        return 0;
345
346    if (av_strstart(line, "fmtp:", &p))
347        return ff_parse_fmtp(s, s->streams[st_index], data, p, parse_fmtp);
348
349    return 0;
350}
351
352const RTPDynamicProtocolHandler ff_mp4v_es_dynamic_handler = {
353    .enc_name           = "MP4V-ES",
354    .codec_type         = AVMEDIA_TYPE_VIDEO,
355    .codec_id           = AV_CODEC_ID_MPEG4,
356    .need_parsing       = AVSTREAM_PARSE_FULL,
357    .priv_data_size     = sizeof(PayloadContext),
358    .parse_sdp_a_line   = parse_sdp_line,
359};
360
361const RTPDynamicProtocolHandler ff_mpeg4_generic_dynamic_handler = {
362    .enc_name           = "mpeg4-generic",
363    .codec_type         = AVMEDIA_TYPE_AUDIO,
364    .codec_id           = AV_CODEC_ID_AAC,
365    .priv_data_size     = sizeof(PayloadContext),
366    .parse_sdp_a_line   = parse_sdp_line,
367    .close              = close_context,
368    .parse_packet       = aac_parse_packet,
369};
370