aboutsummaryrefslogtreecommitdiffstats
path: root/libavformat/rtpdec_xiph.c
blob: 920a8a75bffa94c6fb02668e673e0f53a365e109 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
/*
 * Xiph RTP Protocols
 * Copyright (c) 2009 Colin McQuillian
 * Copyright (c) 2010 Josh Allmann
 *
 * This file is part of Libav.
 *
 * Libav is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * Libav is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * @brief Xiph / RTP Code
 * @author Colin McQuillan <m.niloc@gmail.com>
 * @author Josh Allmann <joshua.allmann@gmail.com>
 */

#include "libavutil/attributes.h"
#include "libavutil/avstring.h"
#include "libavutil/base64.h"
#include "libavcodec/bytestream.h"

#include <assert.h>

#include "avio_internal.h"
#include "rtpdec.h"
#include "rtpdec_formats.h"

/**
 * RTP/Xiph specific private data.
 */
struct PayloadContext {
    unsigned ident;             ///< 24-bit stream configuration identifier
    uint32_t timestamp;
    AVIOContext* fragment;    ///< buffer for split payloads
    uint8_t *split_buf;
    int split_pos, split_buf_len, split_buf_size;
    int split_pkts;
};

static void xiph_close_context(PayloadContext * data)
{
    ffio_free_dyn_buf(&data->fragment);
    av_free(data->split_buf);
}


static int xiph_handle_packet(AVFormatContext *ctx, PayloadContext *data,
                              AVStream *st, AVPacket *pkt, uint32_t *timestamp,
                              const uint8_t *buf, int len, uint16_t seq,
                              int flags)
{

    int ident, fragmented, tdt, num_pkts, pkt_len;

    if (!buf) {
        if (!data->split_buf || data->split_pos + 2 > data->split_buf_len ||
            data->split_pkts <= 0) {
            av_log(ctx, AV_LOG_ERROR, "No more data to return\n");
            return AVERROR_INVALIDDATA;
        }
        pkt_len = AV_RB16(data->split_buf + data->split_pos);
        data->split_pos += 2;
        if (data->split_pos + pkt_len > data->split_buf_len) {
            av_log(ctx, AV_LOG_ERROR, "Not enough data to return\n");
            return AVERROR_INVALIDDATA;
        }
        if (av_new_packet(pkt, pkt_len)) {
            av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
            return AVERROR(ENOMEM);
        }
        pkt->stream_index = st->index;
        memcpy(pkt->data, data->split_buf + data->split_pos, pkt_len);
        data->split_pos += pkt_len;
        data->split_pkts--;
        return data->split_pkts > 0;
    }

    if (len < 6) {
        av_log(ctx, AV_LOG_ERROR, "Invalid %d byte packet\n", len);
        return AVERROR_INVALIDDATA;
    }

    // read xiph rtp headers
    ident       = AV_RB24(buf);
    fragmented  = buf[3] >> 6;
    tdt         = (buf[3] >> 4) & 3;
    num_pkts    = buf[3] & 0xf;
    pkt_len     = AV_RB16(buf + 4);

    if (pkt_len > len - 6) {
        av_log(ctx, AV_LOG_ERROR,
               "Invalid packet length %d in %d byte packet\n", pkt_len,
               len);
        return AVERROR_INVALIDDATA;
    }

    if (ident != data->ident) {
        avpriv_report_missing_feature(ctx, "Xiph SDP configuration change");
        return AVERROR_PATCHWELCOME;
    }

    if (tdt) {
        avpriv_report_missing_feature(ctx,
                                      "RTP Xiph packet settings (%d,%d,%d)",
                                      fragmented, tdt, num_pkts);
        return AVERROR_PATCHWELCOME;
    }

    buf += 6; // move past header bits
    len -= 6;

    if (fragmented == 0) {
        if (av_new_packet(pkt, pkt_len)) {
            av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
            return AVERROR(ENOMEM);
        }
        pkt->stream_index = st->index;
        memcpy(pkt->data, buf, pkt_len);
        buf += pkt_len;
        len -= pkt_len;
        num_pkts--;

        if (num_pkts > 0) {
            if (len > data->split_buf_size || !data->split_buf) {
                av_freep(&data->split_buf);
                data->split_buf_size = 2 * len;
                data->split_buf = av_malloc(data->split_buf_size);
                if (!data->split_buf) {
                    av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
                    av_packet_unref(pkt);
                    return AVERROR(ENOMEM);
                }
            }
            memcpy(data->split_buf, buf, len);
            data->split_buf_len = len;
            data->split_pos = 0;
            data->split_pkts = num_pkts;
            return 1;
        }

        return 0;

    } else if (fragmented == 1) {
        // start of xiph data fragment
        int res;

        // end packet has been lost somewhere, so drop buffered data
        ffio_free_dyn_buf(&data->fragment);

        if((res = avio_open_dyn_buf(&data->fragment)) < 0)
            return res;

        avio_write(data->fragment, buf, pkt_len);
        data->timestamp = *timestamp;

    } else {
        assert(fragmented < 4);
        if (data->timestamp != *timestamp) {
            // skip if fragmented timestamp is incorrect;
            // a start packet has been lost somewhere
            ffio_free_dyn_buf(&data->fragment);
            av_log(ctx, AV_LOG_ERROR, "RTP timestamps don't match!\n");
            return AVERROR_INVALIDDATA;
        }
        if (!data->fragment) {
            av_log(ctx, AV_LOG_WARNING,
                   "Received packet without a start fragment; dropping.\n");
            return AVERROR(EAGAIN);
        }

        // copy data to fragment buffer
        avio_write(data->fragment, buf, pkt_len);

        if (fragmented == 3) {
            // end of xiph data packet
            int ret = ff_rtp_finalize_packet(pkt, &data->fragment, st->index);
            if (ret < 0) {
                av_log(ctx, AV_LOG_ERROR,
                       "Error occurred when getting fragment buffer.");
                return ret;
            }

            return 0;
        }
    }

   return AVERROR(EAGAIN);
}

/**
 * Length encoding described in RFC5215 section 3.1.1.
 */
static int get_base128(const uint8_t ** buf, const uint8_t * buf_end)
{
    int n = 0;
    for (; *buf < buf_end; ++*buf) {
        n <<= 7;
        n += **buf & 0x7f;
        if (!(**buf & 0x80)) {
            ++*buf;
            return n;
        }
    }
    return 0;
}

/**
 * Based off parse_packed_headers in Vorbis RTP
 */
static int
parse_packed_headers(AVFormatContext *s,
                     const uint8_t * packed_headers,
                     const uint8_t * packed_headers_end,
                     AVCodecParameters *par, PayloadContext * xiph_data)
{

    unsigned num_packed, num_headers, length, length1, length2, extradata_alloc;
    uint8_t *ptr;

    if (packed_headers_end - packed_headers < 9) {
        av_log(s, AV_LOG_ERROR,
               "Invalid %td byte packed header.",
               packed_headers_end - packed_headers);
        return AVERROR_INVALIDDATA;
    }

    num_packed         = bytestream_get_be32(&packed_headers);
    xiph_data->ident   = bytestream_get_be24(&packed_headers);
    length             = bytestream_get_be16(&packed_headers);
    num_headers        = get_base128(&packed_headers, packed_headers_end);
    length1            = get_base128(&packed_headers, packed_headers_end);
    length2            = get_base128(&packed_headers, packed_headers_end);

    if (num_packed != 1 || num_headers > 3) {
        avpriv_report_missing_feature(s, "%u packed headers, %u headers",
                                      num_packed, num_headers);
        return AVERROR_PATCHWELCOME;
    }

    if (packed_headers_end - packed_headers != length ||
        length1 > length || length2 > length - length1) {
        av_log(s, AV_LOG_ERROR,
               "Bad packed header lengths (%u,%u,%td,%u)\n", length1,
               length2, packed_headers_end - packed_headers, length);
        return AVERROR_INVALIDDATA;
    }

    /* allocate extra space:
     * -- length/255 +2 for xiphlacing
     * -- one for the '2' marker
     * -- AV_INPUT_BUFFER_PADDING_SIZE required */
    extradata_alloc = length + length/255 + 3 + AV_INPUT_BUFFER_PADDING_SIZE;

    ptr = par->extradata = av_malloc(extradata_alloc);
    if (!ptr) {
        av_log(s, AV_LOG_ERROR, "Out of memory\n");
        return AVERROR(ENOMEM);
    }
    *ptr++ = 2;
    ptr += av_xiphlacing(ptr, length1);
    ptr += av_xiphlacing(ptr, length2);
    memcpy(ptr, packed_headers, length);
    ptr += length;
    par->extradata_size = ptr - par->extradata;
    // clear out remaining parts of the buffer
    memset(ptr, 0, extradata_alloc - par->extradata_size);

    return 0;
}

static int xiph_parse_fmtp_pair(AVFormatContext *s,
                                AVStream* stream,
                                PayloadContext *xiph_data,
                                const char *attr, const char *value)
{
    AVCodecParameters *par = stream->codecpar;
    int result = 0;

    if (!strcmp(attr, "sampling")) {
        if (!strcmp(value, "YCbCr-4:2:0")) {
            par->format = AV_PIX_FMT_YUV420P;
        } else if (!strcmp(value, "YCbCr-4:4:2")) {
            par->format = AV_PIX_FMT_YUV422P;
        } else if (!strcmp(value, "YCbCr-4:4:4")) {
            par->format = AV_PIX_FMT_YUV444P;
        } else {
            av_log(s, AV_LOG_ERROR,
                   "Unsupported pixel format %s\n", attr);
            return AVERROR_INVALIDDATA;
        }
    } else if (!strcmp(attr, "width")) {
        /* This is an integer between 1 and 1048561
         * and MUST be in multiples of 16. */
        par->width = atoi(value);
        return 0;
    } else if (!strcmp(attr, "height")) {
        /* This is an integer between 1 and 1048561
         * and MUST be in multiples of 16. */
        par->height = atoi(value);
        return 0;
    } else if (!strcmp(attr, "delivery-method")) {
        /* Possible values are: inline, in_band, out_band/specific_name. */
        return AVERROR_PATCHWELCOME;
    } else if (!strcmp(attr, "configuration-uri")) {
        /* NOTE: configuration-uri is supported only under 2 conditions:
         *--after the delivery-method tag
         * --with a delivery-method value of out_band */
        return AVERROR_PATCHWELCOME;
    } else if (!strcmp(attr, "configuration")) {
        /* NOTE: configuration is supported only AFTER the delivery-method tag
         * The configuration value is a base64 encoded packed header */
        uint8_t *decoded_packet = NULL;
        int packet_size;
        size_t decoded_alloc = strlen(value) / 4 * 3 + 4;

        if (decoded_alloc <= INT_MAX) {
            decoded_packet = av_malloc(decoded_alloc);
            if (decoded_packet) {
                packet_size =
                    av_base64_decode(decoded_packet, value, decoded_alloc);

                result = parse_packed_headers
                    (s, decoded_packet, decoded_packet + packet_size, par,
                    xiph_data);
            } else {
                av_log(s, AV_LOG_ERROR,
                       "Out of memory while decoding SDP configuration.\n");
                result = AVERROR(ENOMEM);
            }
        } else {
            av_log(s, AV_LOG_ERROR, "Packet too large\n");
            result = AVERROR_INVALIDDATA;
        }
        av_free(decoded_packet);
    }
    return result;
}

static int xiph_parse_sdp_line(AVFormatContext *s, int st_index,
                               PayloadContext *data, const char *line)
{
    const char *p;

    if (st_index < 0)
        return 0;

    if (av_strstart(line, "fmtp:", &p)) {
        return ff_parse_fmtp(s, s->streams[st_index], data, p,
                             xiph_parse_fmtp_pair);
    }

    return 0;
}

RTPDynamicProtocolHandler ff_theora_dynamic_handler = {
    .enc_name         = "theora",
    .codec_type       = AVMEDIA_TYPE_VIDEO,
    .codec_id         = AV_CODEC_ID_THEORA,
    .priv_data_size   = sizeof(PayloadContext),
    .parse_sdp_a_line = xiph_parse_sdp_line,
    .close            = xiph_close_context,
    .parse_packet     = xiph_handle_packet,
};

RTPDynamicProtocolHandler ff_vorbis_dynamic_handler = {
    .enc_name         = "vorbis",
    .codec_type       = AVMEDIA_TYPE_AUDIO,
    .codec_id         = AV_CODEC_ID_VORBIS,
    .need_parsing     = AVSTREAM_PARSE_HEADERS,
    .priv_data_size   = sizeof(PayloadContext),
    .parse_sdp_a_line = xiph_parse_sdp_line,
    .close            = xiph_close_context,
    .parse_packet     = xiph_handle_packet,
};