Statistics
| Branch: | Revision:

ffmpeg / libavformat / rdt.c @ e63a3628

History | View | Annotate | Download (18.1 KB)

1
/*
2
 * Realmedia RTSP protocol (RDT) support.
3
 * Copyright (c) 2007 Ronald S. Bultje
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
/**
23
 * @file
24
 * @brief Realmedia RTSP protocol (RDT) support
25
 * @author Ronald S. Bultje <rbultje@ronald.bitfreak.net>
26
 */
27

    
28
#include "avformat.h"
29
#include "libavutil/avstring.h"
30
#include "rtpdec.h"
31
#include "rdt.h"
32
#include "libavutil/base64.h"
33
#include "libavutil/md5.h"
34
#include "rm.h"
35
#include "internal.h"
36
#include "avio_internal.h"
37
#include "libavcodec/get_bits.h"
38

    
39
struct RDTDemuxContext {
40
    AVFormatContext *ic; /**< the containing (RTSP) demux context */
41
    /** Each RDT stream-set (represented by one RTSPStream) can contain
42
     * multiple streams (of the same content, but with possibly different
43
     * codecs/bitrates). Each such stream is represented by one AVStream
44
     * in the AVFormatContext, and this variable points to the offset in
45
     * that array such that the first is the first stream of this set. */
46
    AVStream **streams;
47
    int n_streams; /**< streams with identifical content in this set */
48
    void *dynamic_protocol_context;
49
    DynamicPayloadPacketHandlerProc parse_packet;
50
    uint32_t prev_timestamp;
51
    int prev_set_id, prev_stream_id;
52
};
53

    
54
RDTDemuxContext *
55
ff_rdt_parse_open(AVFormatContext *ic, int first_stream_of_set_idx,
56
                  void *priv_data, RTPDynamicProtocolHandler *handler)
57
{
58
    RDTDemuxContext *s = av_mallocz(sizeof(RDTDemuxContext));
59
    if (!s)
60
        return NULL;
61

    
62
    s->ic = ic;
63
    s->streams = &ic->streams[first_stream_of_set_idx];
64
    do {
65
        s->n_streams++;
66
    } while (first_stream_of_set_idx + s->n_streams < ic->nb_streams &&
67
             s->streams[s->n_streams]->id == s->streams[0]->id);
68
    s->prev_set_id    = -1;
69
    s->prev_stream_id = -1;
70
    s->prev_timestamp = -1;
71
    s->parse_packet = handler ? handler->parse_packet : NULL;
72
    s->dynamic_protocol_context = priv_data;
73

    
74
    return s;
75
}
76

    
77
void
78
ff_rdt_parse_close(RDTDemuxContext *s)
79
{
80
    av_free(s);
81
}
82

    
83
struct PayloadContext {
84
    AVFormatContext *rmctx;
85
    int nb_rmst;
86
    RMStream **rmst;
87
    uint8_t *mlti_data;
88
    unsigned int mlti_data_size;
89
    char buffer[RTP_MAX_PACKET_LENGTH + FF_INPUT_BUFFER_PADDING_SIZE];
90
    int audio_pkt_cnt; /**< remaining audio packets in rmdec */
91
};
92

    
93
void
94
ff_rdt_calc_response_and_checksum(char response[41], char chksum[9],
95
                                  const char *challenge)
96
{
97
    int ch_len = strlen (challenge), i;
98
    unsigned char zres[16],
99
        buf[64] = { 0xa1, 0xe9, 0x14, 0x9d, 0x0e, 0x6b, 0x3b, 0x59 };
100
#define XOR_TABLE_SIZE 37
101
    const unsigned char xor_table[XOR_TABLE_SIZE] = {
102
        0x05, 0x18, 0x74, 0xd0, 0x0d, 0x09, 0x02, 0x53,
103
        0xc0, 0x01, 0x05, 0x05, 0x67, 0x03, 0x19, 0x70,
104
        0x08, 0x27, 0x66, 0x10, 0x10, 0x72, 0x08, 0x09,
105
        0x63, 0x11, 0x03, 0x71, 0x08, 0x08, 0x70, 0x02,
106
        0x10, 0x57, 0x05, 0x18, 0x54 };
107

    
108
    /* some (length) checks */
109
    if (ch_len == 40) /* what a hack... */
110
        ch_len = 32;
111
    else if (ch_len > 56)
112
        ch_len = 56;
113
    memcpy(buf + 8, challenge, ch_len);
114

    
115
    /* xor challenge bytewise with xor_table */
116
    for (i = 0; i < XOR_TABLE_SIZE; i++)
117
        buf[8 + i] ^= xor_table[i];
118

    
119
    av_md5_sum(zres, buf, 64);
120
    ff_data_to_hex(response, zres, 16, 1);
121

    
122
    /* add tail */
123
    strcpy (response + 32, "01d0a8e3");
124

    
125
    /* calculate checksum */
126
    for (i = 0; i < 8; i++)
127
        chksum[i] = response[i * 4];
128
    chksum[8] = 0;
129
}
130

    
131
static int
132
rdt_load_mdpr (PayloadContext *rdt, AVStream *st, int rule_nr)
133
{
134
    AVIOContext pb;
135
    int size;
136
    uint32_t tag;
137

    
138
    /**
139
     * Layout of the MLTI chunk:
140
     * 4: MLTI
141
     * 2: number of streams
142
     * Then for each stream ([number_of_streams] times):
143
     *     2: mdpr index
144
     * 2: number of mdpr chunks
145
     * Then for each mdpr chunk ([number_of_mdpr_chunks] times):
146
     *     4: size
147
     *     [size]: data
148
     * we skip MDPR chunks until we reach the one of the stream
149
     * we're interested in, and forward that ([size]+[data]) to
150
     * the RM demuxer to parse the stream-specific header data.
151
     */
152
    if (!rdt->mlti_data)
153
        return -1;
154
    ffio_init_context(&pb, rdt->mlti_data, rdt->mlti_data_size, 0,
155
                  NULL, NULL, NULL, NULL);
156
    tag = avio_rl32(&pb);
157
    if (tag == MKTAG('M', 'L', 'T', 'I')) {
158
        int num, chunk_nr;
159

    
160
        /* read index of MDPR chunk numbers */
161
        num = avio_rb16(&pb);
162
        if (rule_nr < 0 || rule_nr >= num)
163
            return -1;
164
        url_fskip(&pb, rule_nr * 2);
165
        chunk_nr = avio_rb16(&pb);
166
        url_fskip(&pb, (num - 1 - rule_nr) * 2);
167

    
168
        /* read MDPR chunks */
169
        num = avio_rb16(&pb);
170
        if (chunk_nr >= num)
171
            return -1;
172
        while (chunk_nr--)
173
            url_fskip(&pb, avio_rb32(&pb));
174
        size = avio_rb32(&pb);
175
    } else {
176
        size = rdt->mlti_data_size;
177
        url_fseek(&pb, 0, SEEK_SET);
178
    }
179
    if (ff_rm_read_mdpr_codecdata(rdt->rmctx, &pb, st, rdt->rmst[st->index], size) < 0)
180
        return -1;
181

    
182
    return 0;
183
}
184

    
185
/**
186
 * Actual data handling.
187
 */
188

    
189
int
190
ff_rdt_parse_header(const uint8_t *buf, int len,
191
                    int *pset_id, int *pseq_no, int *pstream_id,
192
                    int *pis_keyframe, uint32_t *ptimestamp)
193
{
194
    GetBitContext gb;
195
    int consumed = 0, set_id, seq_no, stream_id, is_keyframe,
196
        len_included, need_reliable;
197
    uint32_t timestamp;
198

    
199
    /* skip status packets */
200
    while (len >= 5 && buf[1] == 0xFF /* status packet */) {
201
        int pkt_len;
202

    
203
        if (!(buf[0] & 0x80))
204
            return -1; /* not followed by a data packet */
205

    
206
        pkt_len = AV_RB16(buf+3);
207
        buf += pkt_len;
208
        len -= pkt_len;
209
        consumed += pkt_len;
210
    }
211
    if (len < 16)
212
        return -1;
213
    /**
214
     * Layout of the header (in bits):
215
     * 1:  len_included
216
     *     Flag indicating whether this header includes a length field;
217
     *     this can be used to concatenate multiple RDT packets in a
218
     *     single UDP/TCP data frame and is used to precede RDT data
219
     *     by stream status packets
220
     * 1:  need_reliable
221
     *     Flag indicating whether this header includes a "reliable
222
     *     sequence number"; these are apparently sequence numbers of
223
     *     data packets alone. For data packets, this flag is always
224
     *     set, according to the Real documentation [1]
225
     * 5:  set_id
226
     *     ID of a set of streams of identical content, possibly with
227
     *     different codecs or bitrates
228
     * 1:  is_reliable
229
     *     Flag set for certain streams deemed less tolerable for packet
230
     *     loss
231
     * 16: seq_no
232
     *     Packet sequence number; if >=0xFF00, this is a non-data packet
233
     *     containing stream status info, the second byte indicates the
234
     *     type of status packet (see wireshark docs / source code [2])
235
     * if (len_included) {
236
     *     16: packet_len
237
     * } else {
238
     *     packet_len = remainder of UDP/TCP frame
239
     * }
240
     * 1:  is_back_to_back
241
     *     Back-to-Back flag; used for timing, set for one in every 10
242
     *     packets, according to the Real documentation [1]
243
     * 1:  is_slow_data
244
     *     Slow-data flag; currently unused, according to Real docs [1]
245
     * 5:  stream_id
246
     *     ID of the stream within this particular set of streams
247
     * 1:  is_no_keyframe
248
     *     Non-keyframe flag (unset if packet belongs to a keyframe)
249
     * 32: timestamp (PTS)
250
     * if (set_id == 0x1F) {
251
     *     16: set_id (extended set-of-streams ID; see set_id)
252
     * }
253
     * if (need_reliable) {
254
     *     16: reliable_seq_no
255
     *         Reliable sequence number (see need_reliable)
256
     * }
257
     * if (stream_id == 0x3F) {
258
     *     16: stream_id (extended stream ID; see stream_id)
259
     * }
260
     * [1] https://protocol.helixcommunity.org/files/2005/devdocs/RDT_Feature_Level_20.txt
261
     * [2] http://www.wireshark.org/docs/dfref/r/rdt.html and
262
     *     http://anonsvn.wireshark.org/viewvc/trunk/epan/dissectors/packet-rdt.c
263
     */
264
    init_get_bits(&gb, buf, len << 3);
265
    len_included  = get_bits1(&gb);
266
    need_reliable = get_bits1(&gb);
267
    set_id        = get_bits(&gb, 5);
268
    skip_bits(&gb, 1);
269
    seq_no        = get_bits(&gb, 16);
270
    if (len_included)
271
        skip_bits(&gb, 16);
272
    skip_bits(&gb, 2);
273
    stream_id     = get_bits(&gb, 5);
274
    is_keyframe   = !get_bits1(&gb);
275
    timestamp     = get_bits_long(&gb, 32);
276
    if (set_id == 0x1f)
277
        set_id    = get_bits(&gb, 16);
278
    if (need_reliable)
279
        skip_bits(&gb, 16);
280
    if (stream_id == 0x1f)
281
        stream_id = get_bits(&gb, 16);
282

    
283
    if (pset_id)      *pset_id      = set_id;
284
    if (pseq_no)      *pseq_no      = seq_no;
285
    if (pstream_id)   *pstream_id   = stream_id;
286
    if (pis_keyframe) *pis_keyframe = is_keyframe;
287
    if (ptimestamp)   *ptimestamp   = timestamp;
288

    
289
    return consumed + (get_bits_count(&gb) >> 3);
290
}
291

    
292
/**< return 0 on packet, no more left, 1 on packet, 1 on partial packet... */
293
static int
294
rdt_parse_packet (AVFormatContext *ctx, PayloadContext *rdt, AVStream *st,
295
                  AVPacket *pkt, uint32_t *timestamp,
296
                  const uint8_t *buf, int len, int flags)
297
{
298
    int seq = 1, res;
299
    AVIOContext pb;
300

    
301
    if (rdt->audio_pkt_cnt == 0) {
302
        int pos;
303

    
304
        ffio_init_context(&pb, buf, len, 0, NULL, NULL, NULL, NULL);
305
        flags = (flags & RTP_FLAG_KEY) ? 2 : 0;
306
        res = ff_rm_parse_packet (rdt->rmctx, &pb, st, rdt->rmst[st->index], len, pkt,
307
                                  &seq, flags, *timestamp);
308
        pos = url_ftell(&pb);
309
        if (res < 0)
310
            return res;
311
        if (res > 0) {
312
            if (st->codec->codec_id == CODEC_ID_AAC) {
313
                memcpy (rdt->buffer, buf + pos, len - pos);
314
                rdt->rmctx->pb = avio_alloc_context (rdt->buffer, len - pos, 0,
315
                                                    NULL, NULL, NULL, NULL);
316
            }
317
            goto get_cache;
318
        }
319
    } else {
320
get_cache:
321
        rdt->audio_pkt_cnt =
322
            ff_rm_retrieve_cache (rdt->rmctx, rdt->rmctx->pb,
323
                                  st, rdt->rmst[st->index], pkt);
324
        if (rdt->audio_pkt_cnt == 0 &&
325
            st->codec->codec_id == CODEC_ID_AAC)
326
            av_freep(&rdt->rmctx->pb);
327
    }
328
    pkt->stream_index = st->index;
329
    pkt->pts = *timestamp;
330

    
331
    return rdt->audio_pkt_cnt > 0;
332
}
333

    
334
int
335
ff_rdt_parse_packet(RDTDemuxContext *s, AVPacket *pkt,
336
                    uint8_t **bufptr, int len)
337
{
338
    uint8_t *buf = bufptr ? *bufptr : NULL;
339
    int seq_no, flags = 0, stream_id, set_id, is_keyframe;
340
    uint32_t timestamp;
341
    int rv= 0;
342

    
343
    if (!s->parse_packet)
344
        return -1;
345

    
346
    if (!buf && s->prev_stream_id != -1) {
347
        /* return the next packets, if any */
348
        timestamp= 0; ///< Should not be used if buf is NULL, but should be set to the timestamp of the packet returned....
349
        rv= s->parse_packet(s->ic, s->dynamic_protocol_context,
350
                            s->streams[s->prev_stream_id],
351
                            pkt, &timestamp, NULL, 0, flags);
352
        return rv;
353
    }
354

    
355
    if (len < 12)
356
        return -1;
357
    rv = ff_rdt_parse_header(buf, len, &set_id, &seq_no, &stream_id, &is_keyframe, &timestamp);
358
    if (rv < 0)
359
        return rv;
360
    if (is_keyframe &&
361
        (set_id != s->prev_set_id || timestamp != s->prev_timestamp ||
362
         stream_id != s->prev_stream_id)) {
363
        flags |= RTP_FLAG_KEY;
364
        s->prev_set_id    = set_id;
365
        s->prev_timestamp = timestamp;
366
    }
367
    s->prev_stream_id = stream_id;
368
    buf += rv;
369
    len -= rv;
370

    
371
     if (s->prev_stream_id >= s->n_streams) {
372
         s->prev_stream_id = -1;
373
         return -1;
374
     }
375

    
376
    rv = s->parse_packet(s->ic, s->dynamic_protocol_context,
377
                         s->streams[s->prev_stream_id],
378
                         pkt, &timestamp, buf, len, flags);
379

    
380
    return rv;
381
}
382

    
383
void
384
ff_rdt_subscribe_rule (char *cmd, int size,
385
                       int stream_nr, int rule_nr)
386
{
387
    av_strlcatf(cmd, size, "stream=%d;rule=%d,stream=%d;rule=%d",
388
                stream_nr, rule_nr * 2, stream_nr, rule_nr * 2 + 1);
389
}
390

    
391
static unsigned char *
392
rdt_parse_b64buf (unsigned int *target_len, const char *p)
393
{
394
    unsigned char *target;
395
    int len = strlen(p);
396
    if (*p == '\"') {
397
        p++;
398
        len -= 2; /* skip embracing " at start/end */
399
    }
400
    *target_len = len * 3 / 4;
401
    target = av_mallocz(*target_len + FF_INPUT_BUFFER_PADDING_SIZE);
402
    av_base64_decode(target, p, *target_len);
403
    return target;
404
}
405

    
406
static int
407
rdt_parse_sdp_line (AVFormatContext *s, int st_index,
408
                    PayloadContext *rdt, const char *line)
409
{
410
    AVStream *stream = s->streams[st_index];
411
    const char *p = line;
412

    
413
    if (av_strstart(p, "OpaqueData:buffer;", &p)) {
414
        rdt->mlti_data = rdt_parse_b64buf(&rdt->mlti_data_size, p);
415
    } else if (av_strstart(p, "StartTime:integer;", &p))
416
        stream->first_dts = atoi(p);
417
    else if (av_strstart(p, "ASMRuleBook:string;", &p)) {
418
        int n, first = -1;
419

    
420
        for (n = 0; n < s->nb_streams; n++)
421
            if (s->streams[n]->id == stream->id) {
422
                int count = s->streams[n]->index + 1;
423
                if (first == -1) first = n;
424
                if (rdt->nb_rmst < count) {
425
                    RMStream **rmst= av_realloc(rdt->rmst, count*sizeof(*rmst));
426
                    if (!rmst)
427
                        return AVERROR(ENOMEM);
428
                    memset(rmst + rdt->nb_rmst, 0,
429
                           (count - rdt->nb_rmst) * sizeof(*rmst));
430
                    rdt->rmst    = rmst;
431
                    rdt->nb_rmst = count;
432
                }
433
                rdt->rmst[s->streams[n]->index] = ff_rm_alloc_rmstream();
434
                rdt_load_mdpr(rdt, s->streams[n], (n - first) * 2);
435

    
436
                if (s->streams[n]->codec->codec_id == CODEC_ID_AAC)
437
                    s->streams[n]->codec->frame_size = 1; // FIXME
438
           }
439
    }
440

    
441
    return 0;
442
}
443

    
444
static void
445
real_parse_asm_rule(AVStream *st, const char *p, const char *end)
446
{
447
    do {
448
        /* can be either averagebandwidth= or AverageBandwidth= */
449
        if (sscanf(p, " %*1[Aa]verage%*1[Bb]andwidth=%d", &st->codec->bit_rate) == 1)
450
            break;
451
        if (!(p = strchr(p, ',')) || p > end)
452
            p = end;
453
        p++;
454
    } while (p < end);
455
}
456

    
457
static AVStream *
458
add_dstream(AVFormatContext *s, AVStream *orig_st)
459
{
460
    AVStream *st;
461

    
462
    if (!(st = av_new_stream(s, orig_st->id)))
463
        return NULL;
464
    st->codec->codec_type = orig_st->codec->codec_type;
465
    st->first_dts         = orig_st->first_dts;
466

    
467
    return st;
468
}
469

    
470
static void
471
real_parse_asm_rulebook(AVFormatContext *s, AVStream *orig_st,
472
                        const char *p)
473
{
474
    const char *end;
475
    int n_rules = 0, odd = 0;
476
    AVStream *st;
477

    
478
    /**
479
     * The ASMRuleBook contains a list of comma-separated strings per rule,
480
     * and each rule is separated by a ;. The last one also has a ; at the
481
     * end so we can use it as delimiter.
482
     * Every rule occurs twice, once for when the RTSP packet header marker
483
     * is set and once for if it isn't. We only read the first because we
484
     * don't care much (that's what the "odd" variable is for).
485
     * Each rule contains a set of one or more statements, optionally
486
     * preceeded by a single condition. If there's a condition, the rule
487
     * starts with a '#'. Multiple conditions are merged between brackets,
488
     * so there are never multiple conditions spread out over separate
489
     * statements. Generally, these conditions are bitrate limits (min/max)
490
     * for multi-bitrate streams.
491
     */
492
    if (*p == '\"') p++;
493
    while (1) {
494
        if (!(end = strchr(p, ';')))
495
            break;
496
        if (!odd && end != p) {
497
            if (n_rules > 0)
498
                st = add_dstream(s, orig_st);
499
            else
500
                st = orig_st;
501
            if (!st)
502
                break;
503
            real_parse_asm_rule(st, p, end);
504
            n_rules++;
505
        }
506
        p = end + 1;
507
        odd ^= 1;
508
    }
509
}
510

    
511
void
512
ff_real_parse_sdp_a_line (AVFormatContext *s, int stream_index,
513
                          const char *line)
514
{
515
    const char *p = line;
516

    
517
    if (av_strstart(p, "ASMRuleBook:string;", &p))
518
        real_parse_asm_rulebook(s, s->streams[stream_index], p);
519
}
520

    
521
static PayloadContext *
522
rdt_new_context (void)
523
{
524
    PayloadContext *rdt = av_mallocz(sizeof(PayloadContext));
525

    
526
    av_open_input_stream(&rdt->rmctx, NULL, "", &ff_rdt_demuxer, NULL);
527

    
528
    return rdt;
529
}
530

    
531
static void
532
rdt_free_context (PayloadContext *rdt)
533
{
534
    int i;
535

    
536
    for (i = 0; i < rdt->nb_rmst; i++)
537
        if (rdt->rmst[i]) {
538
            ff_rm_free_rmstream(rdt->rmst[i]);
539
            av_freep(&rdt->rmst[i]);
540
        }
541
    if (rdt->rmctx)
542
        av_close_input_stream(rdt->rmctx);
543
    av_freep(&rdt->mlti_data);
544
    av_freep(&rdt->rmst);
545
    av_free(rdt);
546
}
547

    
548
#define RDT_HANDLER(n, s, t) \
549
static RTPDynamicProtocolHandler ff_rdt_ ## n ## _handler = { \
550
    .enc_name         = s, \
551
    .codec_type       = t, \
552
    .codec_id         = CODEC_ID_NONE, \
553
    .parse_sdp_a_line = rdt_parse_sdp_line, \
554
    .open             = rdt_new_context, \
555
    .close            = rdt_free_context, \
556
    .parse_packet     = rdt_parse_packet \
557
}
558

    
559
RDT_HANDLER(live_video, "x-pn-multirate-realvideo-live", AVMEDIA_TYPE_VIDEO);
560
RDT_HANDLER(live_audio, "x-pn-multirate-realaudio-live", AVMEDIA_TYPE_AUDIO);
561
RDT_HANDLER(video,      "x-pn-realvideo",                AVMEDIA_TYPE_VIDEO);
562
RDT_HANDLER(audio,      "x-pn-realaudio",                AVMEDIA_TYPE_AUDIO);
563

    
564
void av_register_rdt_dynamic_payload_handlers(void)
565
{
566
    ff_register_dynamic_payload_handler(&ff_rdt_video_handler);
567
    ff_register_dynamic_payload_handler(&ff_rdt_audio_handler);
568
    ff_register_dynamic_payload_handler(&ff_rdt_live_video_handler);
569
    ff_register_dynamic_payload_handler(&ff_rdt_live_audio_handler);
570
}