libavformat/rtpdec_xiph.c

   1 /*
   2  * Xiph RTP Protocols
   3  * Copyright (c) 2009 Colin McQuillian
   4  * Copyright (c) 2010 Josh Allmann
   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 Xiph / RTP Code
  26  * @author Colin McQuillan <m.niloc@gmail.com>
  27  * @author Josh Allmann <joshua.allmann@gmail.com>
  28  */
  29
  30 #include "libavutil/avstring.h"
  31 #include "libavutil/base64.h"
  32 #include "libavcodec/bytestream.h"
  33
  34 #include <assert.h>
  35
  36 #include "rtpdec.h"
  37 #include "rtpdec_xiph.h"
  38
  39 /**
  40  * RTP/Xiph specific private data.
  41  */
  42 struct PayloadContext {
  43     unsigned ident;             ///< 24-bit stream configuration identifier
  44     uint32_t timestamp;
  45     ByteIOContext* fragment;    ///< buffer for split payloads
  46 };
  47
  48 static PayloadContext *xiph_new_context(void)
  49 {
  50     return av_mallocz(sizeof(PayloadContext));
  51 }
  52
  53 static inline void free_fragment_if_needed(PayloadContext * data)
  54 {
  55     if (data->fragment) {
  56         uint8_t* p;
  57         url_close_dyn_buf(data->fragment, &p);
  58         av_free(p);
  59         data->fragment = NULL;
  60     }
  61 }
  62
  63 static void xiph_free_context(PayloadContext * data)
  64 {
  65     free_fragment_if_needed(data);
  66     av_free(data);
  67 }
  68
  69 static int xiph_handle_packet(AVFormatContext * ctx,
  70                               PayloadContext * data,
  71                               AVStream * st,
  72                               AVPacket * pkt,
  73                               uint32_t * timestamp,
  74                               const uint8_t * buf, int len, int flags)
  75 {
  76
  77     int ident, fragmented, tdt, num_pkts, pkt_len;
  78
  79     if (len < 6) {
  80         av_log(ctx, AV_LOG_ERROR, "Invalid %d byte packet\n", len);
  81         return AVERROR_INVALIDDATA;
  82     }
  83
  84     // read xiph rtp headers
  85     ident       = AV_RB24(buf);
  86     fragmented  = buf[3] >> 6;
  87     tdt         = (buf[3] >> 4) & 3;
  88     num_pkts    = buf[3] & 7;
  89     pkt_len     = AV_RB16(buf + 4);
  90
  91     if (pkt_len > len - 6) {
  92         av_log(ctx, AV_LOG_ERROR,
  93                "Invalid packet length %d in %d byte packet\n", pkt_len,
  94                len);
  95         return AVERROR_INVALIDDATA;
  96     }
  97
  98     if (ident != data->ident) {
  99         av_log(ctx, AV_LOG_ERROR,
 100                "Unimplemented Xiph SDP configuration change detected\n");
 101         return AVERROR_PATCHWELCOME;
 102     }
 103
 104     if (tdt) {
 105         av_log(ctx, AV_LOG_ERROR,
 106                "Unimplemented RTP Xiph packet settings (%d,%d,%d)\n",
 107                fragmented, tdt, num_pkts);
 108         return AVERROR_PATCHWELCOME;
 109     }
 110
 111     buf += 6; // move past header bits
 112     len -= 6;
 113
 114     if (fragmented == 0) {
 115         // whole frame(s)
 116         int i, data_len, write_len;
 117         buf -= 2;
 118         len += 2;
 119
 120         // fast first pass to calculate total length
 121         for (i = 0, data_len = 0;  (i < num_pkts) && (len >= 2);  i++) {
 122             int off   = data_len + (i << 1);
 123             pkt_len   = AV_RB16(buf + off);
 124             data_len += pkt_len;
 125             len      -= pkt_len + 2;
 126         }
 127
 128         if (len < 0 || i < num_pkts) {
 129             av_log(ctx, AV_LOG_ERROR,
 130                    "Bad packet: %d bytes left at frame %d of %d\n",
 131                    len, i, num_pkts);
 132             return AVERROR_INVALIDDATA;
 133         }
 134
 135         if (av_new_packet(pkt, data_len)) {
 136             av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
 137             return AVERROR(ENOMEM);
 138         }
 139         pkt->stream_index = st->index;
 140
 141         // concatenate frames
 142         for (i = 0, write_len = 0; write_len < data_len; i++) {
 143             pkt_len = AV_RB16(buf);
 144             buf += 2;
 145             memcpy(pkt->data + write_len, buf, pkt_len);
 146             write_len += pkt_len;
 147             buf += pkt_len;
 148         }
 149         assert(write_len == data_len);
 150
 151         return 0;
 152
 153     } else if (fragmented == 1) {
 154         // start of xiph data fragment
 155         int res;
 156
 157         // end packet has been lost somewhere, so drop buffered data
 158         free_fragment_if_needed(data);
 159
 160         if((res = url_open_dyn_buf(&data->fragment)) < 0)
 161             return res;
 162
 163         put_buffer(data->fragment, buf, pkt_len);
 164         data->timestamp = *timestamp;
 165
 166     } else {
 167         assert(fragmented < 4);
 168         if (data->timestamp != *timestamp) {
 169             // skip if fragmented timestamp is incorrect;
 170             // a start packet has been lost somewhere
 171             free_fragment_if_needed(data);
 172             av_log(ctx, AV_LOG_ERROR, "RTP timestamps don't match!\n");
 173             return AVERROR_INVALIDDATA;
 174         }
 175
 176         // copy data to fragment buffer
 177         put_buffer(data->fragment, buf, pkt_len);
 178
 179         if (fragmented == 3) {
 180             // end of xiph data packet
 181             uint8_t* xiph_data;
 182             int frame_size = url_close_dyn_buf(data->fragment, &xiph_data);
 183
 184             if (frame_size < 0) {
 185                 av_log(ctx, AV_LOG_ERROR,
 186                        "Error occurred when getting fragment buffer.");
 187                 return frame_size;
 188             }
 189
 190             if (av_new_packet(pkt, frame_size)) {
 191                 av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
 192                 return AVERROR(ENOMEM);
 193             }
 194
 195             memcpy(pkt->data, xiph_data, frame_size);
 196             pkt->stream_index = st->index;
 197
 198             av_free(xiph_data);
 199             data->fragment = NULL;
 200
 201             return 0;
 202         }
 203     }
 204
 205    return AVERROR(EAGAIN);
 206 }
 207
 208 /**
 209  * Length encoding described in RFC5215 section 3.1.1.
 210  */
 211 static int get_base128(const uint8_t ** buf, const uint8_t * buf_end)
 212 {
 213     int n = 0;
 214     for (; *buf < buf_end; ++*buf) {
 215         n <<= 7;
 216         n += **buf & 0x7f;
 217         if (!(**buf & 0x80)) {
 218             ++*buf;
 219             return n;
 220         }
 221     }
 222     return 0;
 223 }
 224
 225 /**
 226  * Based off parse_packed_headers in Vorbis RTP
 227  */
 228 static unsigned int
 229 parse_packed_headers(const uint8_t * packed_headers,
 230                      const uint8_t * packed_headers_end,
 231                      AVCodecContext * codec, PayloadContext * xiph_data)
 232 {
 233
 234     unsigned num_packed, num_headers, length, length1, length2, extradata_alloc;
 235     uint8_t *ptr;
 236
 237     if (packed_headers_end - packed_headers < 9) {
 238         av_log(codec, AV_LOG_ERROR,
 239                "Invalid %td byte packed header.",
 240                packed_headers_end - packed_headers);
 241         return AVERROR_INVALIDDATA;
 242     }
 243
 244     num_packed         = bytestream_get_be32(&packed_headers);
 245     xiph_data->ident   = bytestream_get_be24(&packed_headers);
 246     length             = bytestream_get_be16(&packed_headers);
 247     num_headers        = get_base128(&packed_headers, packed_headers_end);
 248     length1            = get_base128(&packed_headers, packed_headers_end);
 249     length2            = get_base128(&packed_headers, packed_headers_end);
 250
 251     if (num_packed != 1 || num_headers > 3) {
 252         av_log(codec, AV_LOG_ERROR,
 253                "Unimplemented number of headers: %d packed headers, %d headers\n",
 254                num_packed, num_headers);
 255         return AVERROR_PATCHWELCOME;
 256     }
 257
 258     if (packed_headers_end - packed_headers != length ||
 259         length1 > length || length2 > length - length1) {
 260         av_log(codec, AV_LOG_ERROR,
 261                "Bad packed header lengths (%d,%d,%td,%d)\n", length1,
 262                length2, packed_headers_end - packed_headers, length);
 263         return AVERROR_INVALIDDATA;
 264     }
 265
 266     /* allocate extra space:
 267      * -- length/255 +2 for xiphlacing
 268      * -- one for the '2' marker
 269      * -- FF_INPUT_BUFFER_PADDING_SIZE required */
 270     extradata_alloc = length + length/255 + 3 + FF_INPUT_BUFFER_PADDING_SIZE;
 271
 272     ptr = codec->extradata = av_malloc(extradata_alloc);
 273     if (!ptr) {
 274         av_log(codec, AV_LOG_ERROR, "Out of memory\n");
 275         return AVERROR(ENOMEM);
 276     }
 277     *ptr++ = 2;
 278     ptr += av_xiphlacing(ptr, length1);
 279     ptr += av_xiphlacing(ptr, length2);
 280     memcpy(ptr, packed_headers, length);
 281     ptr += length;
 282     codec->extradata_size = ptr - codec->extradata;
 283     // clear out remaining parts of the buffer
 284     memset(ptr, 0, extradata_alloc - codec->extradata_size);
 285
 286     return 0;
 287 }
 288
 289 static int xiph_parse_fmtp_pair(AVCodecContext * codec,
 290                                 PayloadContext *xiph_data,
 291                                 char *attr, char *value)
 292 {
 293     int result = 0;
 294
 295     if (!strcmp(attr, "sampling")) {
 296         return AVERROR_PATCHWELCOME;
 297     } else if (!strcmp(attr, "width")) {
 298         /* This is an integer between 1 and 1048561
 299          * and MUST be in multiples of 16. */
 300         codec->width = atoi(value);
 301         return 0;
 302     } else if (!strcmp(attr, "height")) {
 303         /* This is an integer between 1 and 1048561
 304          * and MUST be in multiples of 16. */
 305         codec->height = atoi(value);
 306         return 0;
 307     } else if (!strcmp(attr, "delivery-method")) {
 308         /* Possible values are: inline, in_band, out_band/specific_name. */
 309         return AVERROR_PATCHWELCOME;
 310     } else if (!strcmp(attr, "configuration-uri")) {
 311         /* NOTE: configuration-uri is supported only under 2 conditions:
 312          *--after the delivery-method tag
 313          * --with a delivery-method value of out_band */
 314         return AVERROR_PATCHWELCOME;
 315     } else if (!strcmp(attr, "configuration")) {
 316         /* NOTE: configuration is supported only AFTER the delivery-method tag
 317          * The configuration value is a base64 encoded packed header */
 318         uint8_t *decoded_packet = NULL;
 319         int packet_size;
 320         size_t decoded_alloc = strlen(value) / 4 * 3 + 4;
 321
 322         if (decoded_alloc <= INT_MAX) {
 323             decoded_packet = av_malloc(decoded_alloc);
 324             if (decoded_packet) {
 325                 packet_size =
 326                     av_base64_decode(decoded_packet, value, decoded_alloc);
 327
 328                 result = parse_packed_headers
 329                     (decoded_packet, decoded_packet + packet_size, codec,
 330                     xiph_data);
 331             } else {
 332                 av_log(codec, AV_LOG_ERROR,
 333                        "Out of memory while decoding SDP configuration.\n");
 334                 result = AVERROR(ENOMEM);
 335             }
 336         } else {
 337             av_log(codec, AV_LOG_ERROR, "Packet too large\n");
 338             result = AVERROR_INVALIDDATA;
 339         }
 340         av_free(decoded_packet);
 341     }
 342     return result;
 343 }
 344
 345 static int xiph_parse_sdp_line(AVFormatContext *s, int st_index,
 346                                  PayloadContext *data, const char *line)
 347 {
 348     const char *p;
 349     char *value;
 350     char attr[25];
 351     int value_size = strlen(line), attr_size = sizeof(attr), res = 0;
 352     AVCodecContext* codec = s->streams[st_index]->codec;
 353
 354     assert(data);
 355
 356     if (!(value = av_malloc(value_size))) {
 357         av_log(codec, AV_LOG_ERROR, "Out of memory\n");
 358         return AVERROR(ENOMEM);
 359     }
 360
 361     if (av_strstart(line, "fmtp:", &p)) {
 362         // remove protocol identifier
 363         while (*p && *p == ' ') p++; // strip spaces
 364         while (*p && *p != ' ') p++; // eat protocol identifier
 365         while (*p && *p == ' ') p++; // strip trailing spaces
 366
 367         while (ff_rtsp_next_attr_and_value(&p,
 368                                            attr, attr_size,
 369                                            value, value_size)) {
 370             res = xiph_parse_fmtp_pair(codec, data, attr, value);
 371             if (res < 0 && res != AVERROR_PATCHWELCOME)
 372                 return res;
 373         }
 374     }
 375
 376     av_free(value);
 377     return 0;
 378 }
 379
 380 RTPDynamicProtocolHandler ff_theora_dynamic_handler = {
 381     .enc_name         = "theora",
 382     .codec_type       = AVMEDIA_TYPE_VIDEO,
 383     .codec_id         = CODEC_ID_THEORA,
 384     .parse_sdp_a_line = xiph_parse_sdp_line,
 385     .open             = xiph_new_context,
 386     .close            = xiph_free_context,
 387     .parse_packet     = xiph_handle_packet
 388 };
 389
 390 RTPDynamicProtocolHandler ff_vorbis_dynamic_handler = {
 391     .enc_name         = "vorbis",
 392     .codec_type       = AVMEDIA_TYPE_AUDIO,
 393     .codec_id         = CODEC_ID_VORBIS,
 394     .parse_sdp_a_line = xiph_parse_sdp_line,
 395     .open             = xiph_new_context,
 396     .close            = xiph_free_context,
 397     .parse_packet     = xiph_handle_packet
 398 };