libavformat/rtp_asf.c

   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 libavformat/rtp_asf.c
  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 "rtp_asf.h"
  33 #include "rtsp.h"
  34 #include "asf.h"
  35
  36 /**
  37  * From MSDN 2.2.1.4, we learn that ASF data packets over RTP should not
  38  * contain any padding. Unfortunately, the header min/max_pktsize are not
  39  * updated (thus making min_pktsize invalid). Here, we "fix" these faulty
  40  * min_pktsize values in the ASF file header.
  41  * @return 0 on success, <0 on failure (currently -1).
  42  */
  43 static int
  44 rtp_asf_fix_header(uint8_t *buf, int len)
  45 {
  46     uint8_t *p = buf, *end = buf + len;
  47
  48     if (len < sizeof(ff_asf_guid) * 2 + 22 ||
  49         memcmp(p, ff_asf_header, sizeof(ff_asf_guid))) {
  50         return -1;
  51     }
  52     p += sizeof(ff_asf_guid) + 14;
  53     do {
  54         uint64_t chunksize = AV_RL64(p + sizeof(ff_asf_guid));
  55         if (memcmp(p, ff_asf_file_header, sizeof(ff_asf_guid))) {
  56             if (chunksize > end - p)
  57                 return -1;
  58             p += chunksize;
  59             continue;
  60         }
  61
  62         /* skip most of the file header, to min_pktsize */
  63         p += 6 * 8 + 3 * 4 + sizeof(ff_asf_guid) * 2;
  64         if (p + 8 <= end && AV_RL32(p) == AV_RL32(p + 4)) {
  65             /* and set that to zero */
  66             AV_WL32(p, 0);
  67             return 0;
  68         }
  69         break;
  70     } while (end - p >= sizeof(ff_asf_guid) + 8);
  71
  72     return -1;
  73 }
  74
  75 /**
  76  * The following code is basically a buffered ByteIOContext,
  77  * with the added benefit of returning -EAGAIN (instead of 0)
  78  * on packet boundaries, such that the ASF demuxer can return
  79  * safely and resume business at the next packet.
  80  */
  81 static int
  82 packetizer_read(void *opaque, uint8_t *buf, int buf_size)
  83 {
  84     return AVERROR(EAGAIN);
  85 }
  86
  87 static void
  88 init_packetizer(ByteIOContext *pb, uint8_t *buf, int len)
  89 {
  90     init_put_byte(pb, buf, len, 0, NULL, packetizer_read, NULL, NULL);
  91
  92     /* this "fills" the buffer with its current content */
  93     pb->pos     = len;
  94     pb->buf_end = buf + len;
  95 }
  96
  97 void ff_wms_parse_sdp_a_line(AVFormatContext *s, const char *p)
  98 {
  99     if (av_strstart(p, "pgmpu:data:application/vnd.ms.wms-hdr.asfv1;base64,", &p)) {
 100         ByteIOContext pb;
 101         RTSPState *rt = s->priv_data;
 102         int len = strlen(p) * 6 / 8;
 103         char *buf = av_mallocz(len);
 104         av_base64_decode(buf, p, len);
 105
 106         if (rtp_asf_fix_header(buf, len) < 0)
 107             av_log(s, AV_LOG_ERROR,
 108                    "Failed to fix invalid RTSP-MS/ASF min_pktsize\n");
 109         init_packetizer(&pb, buf, len);
 110         if (rt->asf_ctx) {
 111             av_close_input_stream(rt->asf_ctx);
 112             rt->asf_ctx = NULL;
 113         }
 114         av_open_input_stream(&rt->asf_ctx, &pb, "", &asf_demuxer, NULL);
 115         rt->asf_pb_pos = url_ftell(&pb);
 116         av_free(buf);
 117         rt->asf_ctx->pb = NULL;
 118     }
 119 }
 120
 121 static int
 122 asfrtp_parse_sdp_line (AVFormatContext *s, int stream_index,
 123                        PayloadContext *asf, const char *line)
 124 {
 125     if (av_strstart(line, "stream:", &line)) {
 126         RTSPState *rt = s->priv_data;
 127
 128         s->streams[stream_index]->id = strtol(line, NULL, 10);
 129
 130         if (rt->asf_ctx) {
 131             int i;
 132
 133             for (i = 0; i < rt->asf_ctx->nb_streams; i++) {
 134                 if (s->streams[stream_index]->id == rt->asf_ctx->streams[i]->id) {
 135                     *s->streams[stream_index]->codec =
 136                         *rt->asf_ctx->streams[i]->codec;
 137                     rt->asf_ctx->streams[i]->codec->extradata_size = 0;
 138                     rt->asf_ctx->streams[i]->codec->extradata = NULL;
 139                     av_set_pts_info(s->streams[stream_index], 32, 1, 1000);
 140                 }
 141            }
 142         }
 143     }
 144
 145     return 0;
 146 }
 147
 148 struct PayloadContext {
 149     ByteIOContext *pktbuf, pb;
 150     char *buf;
 151 };
 152
 153 /**
 154  * @return 0 when a packet was written into /p pkt, and no more data is left;
 155  *         1 when a packet was written into /p pkt, and more packets might be left;
 156  *        <0 when not enough data was provided to return a full packet, or on error.
 157  */
 158 static int
 159 asfrtp_parse_packet (AVFormatContext *s, PayloadContext *asf, AVStream *st,
 160                      AVPacket *pkt, uint32_t *timestamp,
 161                      const uint8_t *buf, int len, int flags)
 162 {
 163     ByteIOContext *pb = &asf->pb;
 164     int res, mflags, len_off;
 165     RTSPState *rt = s->priv_data;
 166
 167     if (!rt->asf_ctx)
 168         return -1;
 169
 170     if (len > 0) {
 171         int off, out_len;
 172
 173         if (len < 4)
 174             return -1;
 175
 176         init_put_byte(pb, buf, len, 0, NULL, NULL, NULL, NULL);
 177         mflags = get_byte(pb);
 178         if (mflags & 0x80)
 179             flags |= RTP_FLAG_KEY;
 180         len_off = get_be24(pb);
 181         if (mflags & 0x20)   /**< relative timestamp */
 182             url_fskip(pb, 4);
 183         if (mflags & 0x10)   /**< has duration */
 184             url_fskip(pb, 4);
 185         if (mflags & 0x8)    /**< has location ID */
 186             url_fskip(pb, 4);
 187         off = url_ftell(pb);
 188
 189         av_freep(&asf->buf);
 190         if (!(mflags & 0x40)) {
 191             /**
 192              * If 0x40 is not set, the len_off field specifies an offset of this
 193              * packet's payload data in the complete (reassembled) ASF packet.
 194              * This is used to spread one ASF packet over multiple RTP packets.
 195              */
 196             if (asf->pktbuf && len_off != url_ftell(asf->pktbuf)) {
 197                 uint8_t *p;
 198                 url_close_dyn_buf(asf->pktbuf, &p);
 199                 asf->pktbuf = NULL;
 200                 av_free(p);
 201             }
 202             if (!len_off && !asf->pktbuf &&
 203                 !(res = url_open_dyn_packet_buf(&asf->pktbuf, rt->asf_ctx->packet_size)))
 204                 return res;
 205             if (!asf->pktbuf)
 206                 return AVERROR(EIO);
 207
 208             put_buffer(asf->pktbuf, buf + off, len - off);
 209             if (!(flags & RTP_FLAG_MARKER))
 210                 return -1;
 211             out_len     = url_close_dyn_buf(asf->pktbuf, &asf->buf);
 212             asf->pktbuf = NULL;
 213         } else {
 214             /**
 215              * If 0x40 is set, the len_off field specifies the length of the
 216              * next ASF packet that can be read from this payload data alone.
 217              * This is commonly the same as the payload size, but could be
 218              * less in case of packet splitting (i.e. multiple ASF packets in
 219              * one RTP packet).
 220              */
 221             if (len_off != len) {
 222                 av_log_missing_feature(s,
 223                     "RTSP-MS packet splitting", 1);
 224                 return -1;
 225             }
 226             asf->buf = av_malloc(len - off);
 227             out_len  = len - off;
 228             memcpy(asf->buf, buf + off, len - off);
 229         }
 230
 231         init_packetizer(pb, asf->buf, out_len);
 232         pb->pos += rt->asf_pb_pos;
 233         pb->eof_reached = 0;
 234         rt->asf_ctx->pb = pb;
 235     }
 236
 237     for (;;) {
 238         int i;
 239
 240         res = av_read_packet(rt->asf_ctx, pkt);
 241         rt->asf_pb_pos = url_ftell(pb);
 242         if (res != 0)
 243             break;
 244         for (i = 0; i < s->nb_streams; i++) {
 245             if (s->streams[i]->id == rt->asf_ctx->streams[pkt->stream_index]->id) {
 246                 pkt->stream_index = i;
 247                 return 1; // FIXME: return 0 if last packet
 248             }
 249         }
 250         av_free_packet(pkt);
 251     }
 252
 253     return res == 1 ? -1 : res;
 254 }
 255
 256 static PayloadContext *
 257 asfrtp_new_context (void)
 258 {
 259     return av_mallocz(sizeof(PayloadContext));
 260 }
 261
 262 static void
 263 asfrtp_free_context (PayloadContext *asf)
 264 {
 265     if (asf->pktbuf) {
 266         uint8_t *p = NULL;
 267         url_close_dyn_buf(asf->pktbuf, &p);
 268         asf->pktbuf = NULL;
 269         av_free(p);
 270     }
 271     av_freep(&asf->buf);
 272     av_free(asf);
 273 }
 274
 275 #define RTP_ASF_HANDLER(n, s, t) \
 276 RTPDynamicProtocolHandler ff_ms_rtp_ ## n ## _handler = { \
 277     s, \
 278     t, \
 279     CODEC_ID_NONE, \
 280     asfrtp_parse_sdp_line, \
 281     asfrtp_new_context, \
 282     asfrtp_free_context, \
 283     asfrtp_parse_packet,   \
 284 };
 285
 286 RTP_ASF_HANDLER(asf_pfv, "x-asf-pf",  CODEC_TYPE_VIDEO);
 287 RTP_ASF_HANDLER(asf_pfa, "x-asf-pf",  CODEC_TYPE_AUDIO);