1/* 2 * Microsoft RTP/ASF support. 3 * Copyright (c) 2008 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 Microsoft RTP/ASF support 25 * @author Ronald S. Bultje <rbultje@ronald.bitfreak.net> 26 */ 27 28#include "libavutil/base64.h" 29#include "libavutil/avstring.h" 30#include "libavutil/intreadwrite.h" 31#include "rtp.h" 32#include "rtpdec_formats.h" 33#include "rtsp.h" 34#include "asf.h" 35#include "avio_internal.h" 36#include "internal.h" 37 38/** 39 * From MSDN 2.2.1.4, we learn that ASF data packets over RTP should not 40 * contain any padding. Unfortunately, the header min/max_pktsize are not 41 * updated (thus making min_pktsize invalid). Here, we "fix" these faulty 42 * min_pktsize values in the ASF file header. 43 * @return 0 on success, <0 on failure (currently -1). 44 */ 45static int rtp_asf_fix_header(uint8_t *buf, int len) 46{ 47 uint8_t *p = buf, *end = buf + len; 48 49 if (len < sizeof(ff_asf_guid) * 2 + 22 || 50 memcmp(p, ff_asf_header, sizeof(ff_asf_guid))) { 51 return -1; 52 } 53 p += sizeof(ff_asf_guid) + 14; 54 do { 55 uint64_t chunksize = AV_RL64(p + sizeof(ff_asf_guid)); 56 if (memcmp(p, ff_asf_file_header, sizeof(ff_asf_guid))) { 57 if (chunksize > end - p) 58 return -1; 59 p += chunksize; 60 continue; 61 } 62 63 /* skip most of the file header, to min_pktsize */ 64 p += 6 * 8 + 3 * 4 + sizeof(ff_asf_guid) * 2; 65 if (p + 8 <= end && AV_RL32(p) == AV_RL32(p + 4)) { 66 /* and set that to zero */ 67 AV_WL32(p, 0); 68 return 0; 69 } 70 break; 71 } while (end - p >= sizeof(ff_asf_guid) + 8); 72 73 return -1; 74} 75 76/** 77 * The following code is basically a buffered AVIOContext, 78 * with the added benefit of returning -EAGAIN (instead of 0) 79 * on packet boundaries, such that the ASF demuxer can return 80 * safely and resume business at the next packet. 81 */ 82static int packetizer_read(void *opaque, uint8_t *buf, int buf_size) 83{ 84 return AVERROR(EAGAIN); 85} 86 87static void init_packetizer(AVIOContext *pb, uint8_t *buf, int len) 88{ 89 ffio_init_context(pb, buf, len, 0, NULL, packetizer_read, NULL, NULL); 90 91 /* this "fills" the buffer with its current content */ 92 pb->pos = len; 93 pb->buf_end = buf + len; 94} 95 96int ff_wms_parse_sdp_a_line(AVFormatContext *s, const char *p) 97{ 98 int ret = 0; 99 if (av_strstart(p, "pgmpu:data:application/vnd.ms.wms-hdr.asfv1;base64,", &p)) { 100 AVIOContext pb; 101 RTSPState *rt = s->priv_data; 102 AVDictionary *opts = NULL; 103 int len = strlen(p) * 6 / 8; 104 char *buf = av_mallocz(len); 105 av_base64_decode(buf, p, len); 106 107 if (rtp_asf_fix_header(buf, len) < 0) 108 av_log(s, AV_LOG_ERROR, 109 "Failed to fix invalid RTSP-MS/ASF min_pktsize\n"); 110 init_packetizer(&pb, buf, len); 111 if (rt->asf_ctx) { 112 avformat_close_input(&rt->asf_ctx); 113 } 114 if (!(rt->asf_ctx = avformat_alloc_context())) 115 return AVERROR(ENOMEM); 116 rt->asf_ctx->pb = &pb; 117 av_dict_set(&opts, "no_resync_search", "1", 0); 118 ret = avformat_open_input(&rt->asf_ctx, "", &ff_asf_demuxer, &opts); 119 av_dict_free(&opts); 120 if (ret < 0) 121 return ret; 122 av_dict_copy(&s->metadata, rt->asf_ctx->metadata, 0); 123 rt->asf_pb_pos = avio_tell(&pb); 124 av_free(buf); 125 rt->asf_ctx->pb = NULL; 126 } 127 return ret; 128} 129 130static int asfrtp_parse_sdp_line(AVFormatContext *s, int stream_index, 131 PayloadContext *asf, const char *line) 132{ 133 if (stream_index < 0) 134 return 0; 135 if (av_strstart(line, "stream:", &line)) { 136 RTSPState *rt = s->priv_data; 137 138 s->streams[stream_index]->id = strtol(line, NULL, 10); 139 140 if (rt->asf_ctx) { 141 int i; 142 143 for (i = 0; i < rt->asf_ctx->nb_streams; i++) { 144 if (s->streams[stream_index]->id == rt->asf_ctx->streams[i]->id) { 145 *s->streams[stream_index]->codec = 146 *rt->asf_ctx->streams[i]->codec; 147 s->streams[stream_index]->need_parsing = 148 rt->asf_ctx->streams[i]->need_parsing; 149 rt->asf_ctx->streams[i]->codec->extradata_size = 0; 150 rt->asf_ctx->streams[i]->codec->extradata = NULL; 151 avpriv_set_pts_info(s->streams[stream_index], 32, 1, 1000); 152 } 153 } 154 } 155 } 156 157 return 0; 158} 159 160struct PayloadContext { 161 AVIOContext *pktbuf, pb; 162 uint8_t *buf; 163}; 164 165/** 166 * @return 0 when a packet was written into /p pkt, and no more data is left; 167 * 1 when a packet was written into /p pkt, and more packets might be left; 168 * <0 when not enough data was provided to return a full packet, or on error. 169 */ 170static int asfrtp_parse_packet(AVFormatContext *s, PayloadContext *asf, 171 AVStream *st, AVPacket *pkt, 172 uint32_t *timestamp, 173 const uint8_t *buf, int len, uint16_t seq, 174 int flags) 175{ 176 AVIOContext *pb = &asf->pb; 177 int res, mflags, len_off; 178 RTSPState *rt = s->priv_data; 179 180 if (!rt->asf_ctx) 181 return -1; 182 183 if (len > 0) { 184 int off, out_len = 0; 185 186 if (len < 4) 187 return -1; 188 189 av_freep(&asf->buf); 190 191 ffio_init_context(pb, buf, len, 0, NULL, NULL, NULL, NULL); 192 193 while (avio_tell(pb) + 4 < len) { 194 int start_off = avio_tell(pb); 195 196 mflags = avio_r8(pb); 197 if (mflags & 0x80) 198 flags |= RTP_FLAG_KEY; 199 len_off = avio_rb24(pb); 200 if (mflags & 0x20) /**< relative timestamp */ 201 avio_skip(pb, 4); 202 if (mflags & 0x10) /**< has duration */ 203 avio_skip(pb, 4); 204 if (mflags & 0x8) /**< has location ID */ 205 avio_skip(pb, 4); 206 off = avio_tell(pb); 207 208 if (!(mflags & 0x40)) { 209 /** 210 * If 0x40 is not set, the len_off field specifies an offset 211 * of this packet's payload data in the complete (reassembled) 212 * ASF packet. This is used to spread one ASF packet over 213 * multiple RTP packets. 214 */ 215 if (asf->pktbuf && len_off != avio_tell(asf->pktbuf)) { 216 uint8_t *p; 217 avio_close_dyn_buf(asf->pktbuf, &p); 218 asf->pktbuf = NULL; 219 av_free(p); 220 } 221 if (!len_off && !asf->pktbuf && 222 (res = avio_open_dyn_buf(&asf->pktbuf)) < 0) 223 return res; 224 if (!asf->pktbuf) 225 return AVERROR(EIO); 226 227 avio_write(asf->pktbuf, buf + off, len - off); 228 avio_skip(pb, len - off); 229 if (!(flags & RTP_FLAG_MARKER)) 230 return -1; 231 out_len = avio_close_dyn_buf(asf->pktbuf, &asf->buf); 232 asf->pktbuf = NULL; 233 } else { 234 /** 235 * If 0x40 is set, the len_off field specifies the length of 236 * the next ASF packet that can be read from this payload 237 * data alone. This is commonly the same as the payload size, 238 * but could be less in case of packet splitting (i.e. 239 * multiple ASF packets in one RTP packet). 240 */ 241 242 int cur_len = start_off + len_off - off; 243 int prev_len = out_len; 244 out_len += cur_len; 245 if (FFMIN(cur_len, len - off) < 0) 246 return -1; 247 if ((res = av_reallocp(&asf->buf, out_len)) < 0) 248 return res; 249 memcpy(asf->buf + prev_len, buf + off, 250 FFMIN(cur_len, len - off)); 251 avio_skip(pb, cur_len); 252 } 253 } 254 255 init_packetizer(pb, asf->buf, out_len); 256 pb->pos += rt->asf_pb_pos; 257 pb->eof_reached = 0; 258 rt->asf_ctx->pb = pb; 259 } 260 261 for (;;) { 262 int i; 263 264 res = ff_read_packet(rt->asf_ctx, pkt); 265 rt->asf_pb_pos = avio_tell(pb); 266 if (res != 0) 267 break; 268 for (i = 0; i < s->nb_streams; i++) { 269 if (s->streams[i]->id == rt->asf_ctx->streams[pkt->stream_index]->id) { 270 pkt->stream_index = i; 271 return 1; // FIXME: return 0 if last packet 272 } 273 } 274 av_free_packet(pkt); 275 } 276 277 return res == 1 ? -1 : res; 278} 279 280static PayloadContext *asfrtp_new_context(void) 281{ 282 return av_mallocz(sizeof(PayloadContext)); 283} 284 285static void asfrtp_free_context(PayloadContext *asf) 286{ 287 if (asf->pktbuf) { 288 uint8_t *p = NULL; 289 avio_close_dyn_buf(asf->pktbuf, &p); 290 asf->pktbuf = NULL; 291 av_free(p); 292 } 293 av_freep(&asf->buf); 294 av_free(asf); 295} 296 297#define RTP_ASF_HANDLER(n, s, t) \ 298RTPDynamicProtocolHandler ff_ms_rtp_ ## n ## _handler = { \ 299 .enc_name = s, \ 300 .codec_type = t, \ 301 .codec_id = AV_CODEC_ID_NONE, \ 302 .parse_sdp_a_line = asfrtp_parse_sdp_line, \ 303 .alloc = asfrtp_new_context, \ 304 .free = asfrtp_free_context, \ 305 .parse_packet = asfrtp_parse_packet, \ 306} 307 308RTP_ASF_HANDLER(asf_pfv, "x-asf-pf", AVMEDIA_TYPE_VIDEO); 309RTP_ASF_HANDLER(asf_pfa, "x-asf-pf", AVMEDIA_TYPE_AUDIO); 310